JP2004139411A - Brush drawing device, brush drawing program and brush drawing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve natural brush drawing by using a tablet. <P>SOLUTION: This brush drawing device 100 comprises a coordinate value detecting part 502 and a pressure detecting part 503 for detecting at preset time intervals coordinate values for coordinates input by a tablet pen 103 and drawing pressure, respectively, a drawing pattern expanding/contracting part 504 for expanding/contracting the size of a drawing pattern in accordance with the drawing pressure, a drawing pattern rotating part 506 for rotating the drawing pattern along the moving direction of the tablet pen 103, a rotation control part 508 for reducing the rotation amount of the drawing pattern when a space between the coordinate values is small, and a drawing part 511 for drawing the drawing pattern, which is rotated by the drawing pattern rotating part 506 or the rotation control part 508 and expanded/contracted by the drawing pattern expanding/contracting part 504, on coordinate positions detected by the coordinate value detecting part 502, in sequence. <P>COPYRIGHT: (C)2004,JPO

Description

なお、この計算式で使用する筆圧最大時の筆の長さ（Ｌ１）、根元の幅（Ｗ２）、筆先の幅（Ｗ１）を可変パラメータとして自由に筆の初期サイズ（大筆、中筆、小筆）を変更できるようにしてもよい。
【００７０】
上式では、筆圧が大きくなるほど筆先が広がっていく描画モデルとしたが、筆先形状が筆圧に依存しない描画モデルを採用してもよい（図６（ｃ）参照）。この場合には、書きはじめや細字の描画が太く不自然とならないように筆先の閉じた描画パタンを使用することが好ましい。
【００７１】
圧力検知部５０３は、たとえば、タブレット１５０と、ドライバソフト４４３などによりその機能を実現することができる。描画パタン拡大縮小部５０４は、たとえば、ＣＰＵ４０１と、ＲＡＭ４０３と、毛筆ソフト４４２などによりその機能を実現することができる。
【００７２】
移動方向算出部５０５は、座標値検出部５０２で順次検出された座標値に基づいてタブレットペン１０３の移動方向を算出する。描画パタン回転部５０６は、移動方向算出部５０５で算出された移動方向の反対方向に描画パタンの筆先部分が向くように描画パタンを回転させる。毛筆描画装置１００では、タブレット板１０２のサンプリング点（順次検出される座標値）に対応させて描画パタンを描画すると共に、サンプリング点の間を補間することにより毛筆描画をおこなうが、描画パタン回転部５０６は、各サンプリング点で、筆の進行方向に従って筆先の向きを変える処理をおこなう。
【００７３】
このときの処理として、まず、タブレットペン１０３を降ろした際の筆先初期角度を決定する必要がある。毛筆描画装置１００では、タブレットペン１０３が座標入力を開始した位置（タブレット板１０２に接触した位置）から、一定以上の距離を移動するまでのサンプリング点をスキップし、一定の距離を超えたところの座標値と入力開始時の座標値とからタブレットペン１０３の進行方向を求め、この方向に応じて描画パタンの向き（初期角度）を計算する方法を採用している。
【００７４】
これは、筆の着紙前後では手ぶれが発生しやすく、たとえばタブレットペン１０３が降ろされる直前のサンプリング点と、タブレットペン１０３がタブレット板１０２に触れた（座標入力を開始した）ときのサンプリング点から筆の進行方向を求め初期角度を計算すると、筆の移動量も小さく演算誤差が非常に大きくなるからである。なお、初期角度を決定するためのタブレットペン１０３の移動距離のしきい値としては、描画パタンの最大長Ｌ１の４分の１とすることができる（図７参照）。
【００７５】
移動方向算出部５０５と描画パタン回転部５０６は、初期角度の決定後、順次各サンプリング点を結ぶ直線の向きを求め、描画パタンの筆先を回転する。直前のタブレットペン１０３の位置を（ｘ_ｉ−１，ｙ_ｉ−１）、現在の位置を（ｘ_ｉ，ｙ_ｉ）とすると、描画パタンの向きθは
θ＝Ｔａｎ^−１（−（ｙ_ｉ−ｙ_ｉ−１）／（ｘ_ｉ−ｘ_ｉ−１））　・・・式（１）
となる。なお、図８に、描画パタンの向きθとタブレットペンの移動方向の関係を示す。
【００７６】
移動方向算出部５０５は、たとえば、ドライバソフト４４３と、ＲＡＭ４０３と、ＣＰＵ４０１と、毛筆描画ソフト４４２などによりその機能を実現することができる。描画パタン回転部５０６は、たとえば、ＲＡＭ４０３と、ＣＰＵ４０１と毛筆描画ソフト４４２などによりその機能を実現することができる。
【００７７】
距離間隔算出部５０７は、座標値検出部５０２で順次検出された座標値の隣り合う距離間隔を算出する。また、回転制御部５０８は、距離間隔算出部５０７で算出された座標値の距離間隔に基づいて、描画パタン回転部５０６を制御し、描画パタンの回転量を小さくする。すなわち、回転制御部５０８では、カド部分における「慣性」を考慮した描画を実現する。換言すれば、カド部分での不自然な突起描画を防止する。
【００７８】
現実の毛筆描画を詳細に観察すると、実際には、カド部分では、摩擦などの要因により筆の向きは急激に変化せず、少し遅れて緩やかに変化する。毛筆描画装置１００は、このような特性を表現するため「慣性」というパラメータを設け、筆の向き（描画パタンの回転）の変化度合いを自由に調整できるようにしている。なおタブレットペン１０３を降ろしたときの初期角度以外は、この慣性パラメータによって筆の向きの変化量を調整するようにする。
【００７９】
毛筆描画装置１００で慣性を用いて描画をおこなう場合、回転制御部５０８は、回転角度θ‘_ｉを次式により計算する。
θ‘_ｉ　＝　θ‘_ｉ−１＋　（１００−ｍ）・Δθ_ｉ　／　１００　・・・式（２）
Δθ_ｉ　＝　θ_ｉ−θ‘_ｉ−１　（−π＜Δθ_ｉ≦π）
ここで、
θ‘_ｉ−１　　サンプリング点ｉ−１における回転角度（慣性あり）
θ_ｉ　　　　移動方向算出部５０５で求めたサンプリング点ｉにおけるタブレットペン１０３の移動方向の反対方向（慣性なし）
Δθ_ｉ　　　サンプリング点ｉ−１における回転角度の変化量（−π〜π）
ｍ　　　　慣性（０〜１００）
なお、θ‘_ｉ−１は着紙直後（座標入力の開始直後）では前述した初期角度を使用し、それ以外では直前のサンプリング点で式（２）により計算した回転角度を使用する。Δθ_ｉは、−π〜πの範囲に正規化した角度を使用する。
【００８０】
式（２）から明らかなように、慣性ｍの値が大きいほど回転が緩やかになる。ｍ＝１００の場合は全く回転せず（θ‘_ｉ　＝θ‘_ｉ−１）、ｍ＝１００の場合はタブレットペン１０３の進行方向の反対向きθ‘_ｉ＝θ_ｉとなる。
【００８１】
以上は、慣性ｍを用いた描画パタンの向きの決定する処理であるが、毛筆描画装置１００では、この慣性ｍをタブレットペン１０３の移動速度に応じて変化させる。これにより、単に座標値検出部５０２で検出された位置に描画パタンを順次重ね合わせて描画していく場合に、文字の折り返し部分で生じる不自然な突起を防ぐことができる。図９は、カドにおける不自然な突起描画と、慣性を制御した場合の描画パタンの向きを示した描画概念図である。このうち、図９（ａ）は、慣性を考慮しない描画図であり、図９（ｂ）は、図９（ａ）で示した描画についてカド部分前後の描画パタンの配向を示した図であり、図９（ｃ）は、慣性を考慮した描画パタンの配向を示した図である。
【００８２】
不自然な突起は、特に、ゆっくりとペンを動かした場合に、ペンが下方に下がりきらないうちに描画パタンが回転してしまうことに起因する。回転制御部５０８は、タブレットペン１０３の移動速度が遅いときに慣性ｍが高くなるように回転制御する。回転制御はたとえば以下の式を採用することができる。
ｍ’　_ｉ　＝　ＭＡＸ（１００−ｒｆ_ｉ，　ｍ）
ｒｆ_ｉ　＝　（Ｄ_ｉ ^２・α）　／　（　ＭＡＸ（ｌ１_ｉ，　ｌ１_ｉ−１）　＋　１　）　＋　β
（但し、Ｄ_ｉ＝０の場合はｒｆ_ｉ＝０）
Ｄ_ｉ ^２　＝　（ｘ_ｉ−ｘ_ｉ−１）^２　＋　（ｙ_ｉ−ｙ_ｉ−１）^２
ここで、
ｍ’　_ｉ　　　サンプリング点ｉにおける補正済みの慣性値（０〜１００）
ｍ　　　　補正前の慣性値（０〜１００）（下限値として使用）
ｒｆ_ｉ　　　　サンプリング点ｉにおける回転係数
Ｄ_ｉ　　　　サンプリング点ｉとサンプリング点ｉ−１との距離
ｌ１_ｉ　　　　サンプリング点ｉにおける描画パタンの長さ
ｌ１_ｉ−１　　　サンプリング点ｉ−１における描画パタンの長さ
α，β　　　微調整のための定数（例えばα＝１０、β＝３）
ｘ_ｉ，　ｙ_ｉ　　　サンプリング点ｉの座標値
ｘ_ｉ−１，　ｙ_ｉ−１　　サンプリング点ｉ−１の座標値
なお、座標は整数値で管理するものとする。
従って、最終的な回転角度θ‘_ｉは下式となる。
θ‘_ｉ　＝　θ‘_ｉ−１＋　（１００−ｍ’　_ｉ）・Δθ_ｉ　／　１００　・・・式（３）
【００８３】
以上のようにタブレットペン１０３の移動速度に従って慣性値ｍを変化させながら描画をおこなうことにより、カドの部分での不自然な突起描画が抑制される。また、カドの部分に限らず、ペンをゆっくり移動させた場合には手ぶれや演算誤差の増大によって線の途中に不自然な盛り上がりが生じうるが、この現象についても同時に解消される。距離間隔算出部５０７は、たとえば、毛筆描画ソフト４４２と、ＲＡＭ４０３と、ＣＰＵ４０１などによりその機能を実現することができる。回転制御部５０８は、たとえば、毛筆描画ソフト４４２と、ＲＡＭ４０３と、ＣＰＵ４０１などによりその機能を実現することができる。
【００８４】
転回判定部５０９は、移動方向算出部５０５で算出された移動方向が急転回したか否かを判定する。また、描画パタン短縮部５１０は、転回判定部５０９で移動方向が急転回したと判定された場合に、所定の描画個数分または所定の描画距離分だけ描画パタンの長さを短くする。折り返しのような１８０度に近い大幅な方向転換を行った場合には、慣性を考慮しても不自然な突起が描かれる場合があり（図１０参照）、描画パタン短縮部５１０は、この突起描画を防止する。
【００８５】
現実の毛筆描画を詳細に観察すると、実際には、折り返し部分では、筆先が裏返えることにより綺麗な描画が実現されている。毛筆描画装置１００は、筆先の裏返りをシミュレートすることにより、この問題に対処している。具体的には、まず、筆先の裏返りを判定するために、各サンプリング点において筆先回転率ｒｒ_ｉを計算する
ｒｒ_ｉ　＝　｜Δθ_ｉ｜・１００　／　π　　　　・・・式（４）
Δθ_ｉ　＝　θ_ｉ−θ‘_ｉ−１　（−π＜Δθ_ｉ≦π）
ここで、
ｒｒ_ｉ　　　サンプリング点ｉにおける筆先回転率
θ‘_ｉ−１　　式（３）により求めたサンプリング点ｉ−１における回転角度（慣性あり）
θ_ｉ　　　式（１）により求めたサンプリング点ｉにおける回転角度（慣性なし）
Δθ_ｉ　　サンプリング点ｉ−１における回転角度の変化量（−π〜π）
【００８６】
転回判定部５０９は、式（４）により計算した筆先回転率ｒｒ_ｉが一定値以上の場合に筆先が裏返った、すなわち、移動方向が急転回したと判断する。この一定値は、たとえば、８０とすることができる。毛筆描画装置１００は、筆先が裏返ったと判定した場合は筆先反転フラグをセットし、そのサンプリング点での座標値（ｔｘ，ｔｙ）　を保存し、回転角度をθ‘_ｉ−１＝θ_ｉ、θ‘_ｉ＝θ_ｉとして描画をおこなう。
【００８７】
描画パタン短縮部５１０は、筆先反転フラグがセットされているときは、一時的に筆先の長さを短くした描画パタンを採用する。筆先の長さｌ１_ｉ‘としては、たとえば、下式により計算することができる。
ｌ１_ｉ’　＝　Ｄｔ_ｉ・（ｌ１_ｉ−ｗ２_ｉ）　／　Ｌ１　＋　ｗ２_ｉ　　　（丸筆の場合）
ｌ１_ｉ’　＝　Ｄｔ_ｉ・ｌ１_ｉ　／　Ｌ１　　　（平筆の場合）
Ｄｔ_ｉ　＝　ｓｑｒｔ（（ｘ_ｉ−ｔ_ｘ）^２＋（ｙ_ｉ−ｔ_ｙ）^２）
但し、Ｄｔ_ｉ＞Ｌ１の場合はＤｔ_ｉ＝Ｌ１
ここで、
Ｄｔ_ｉ　　　　サンプリング点ｉの折り返り点からの距離
ｘ_ｉ，　ｙ_ｉ　　　サンプリング点ｉの座標値
ｔｘ，ｔｙ　　　折り返り点の座標値
ｗ２_ｉ　　　　サンプリング点ｉでの描画パタンの根元部分の幅
ｌ１_ｉ　　　　　サンプリング点ｉにおける描画パタンの長さ
Ｌ１　　　　　描画パタンの最大長
なお、サンプリング点ｉの折り返り点からの距離Ｄｔ_ｉは下記の式により近似してもよい。
Ｄｔ_ｉ　＝　｜ｘ_ｉ−ｔｘ｜　＋　｜ｙ_ｉ−ｔｙ｜　但し、Ｄｔ_ｉ＞Ｌ１の場合はＤｔ_ｉ＝Ｌ１
【００８８】
転回判定部５０９は、Ｄｔ_ｉ≧Ｌ１となった時点で筆先反転フラグをクリアする処理をおこなう。このように、筆先が裏返ったと判断された場合、一時的に筆先の長さを短く補正して円に近い描画パタンで描画をおこなうことにより、筆先の裏返りをシミュレートし、大幅な方向転換を行った場合すなわち折り返し点での描画の不具合を解消することができる。
【００８９】
転回判定部５０９は、たとえば、毛筆描画ソフト４４２と、ＲＡＭ４０３と、ＣＰＵ４０１などによりその機能を実現することができる。なお、タブレットペン１０３が座標入力面１２１に対する傾きを検出する傾き検出機能を備えている場合には、タブレットペン１０３も転回判定部５０９の機能的構成要素となる。描画パタン短縮部５１０は、たとえば、毛筆描画ソフト４４２と、ＲＡＭ４０３と、ＣＰＵ４０１などによりその機能を実現することができる。
【００９０】
描画部５１１は、描画パタン回転部５０６または回転制御部５０８で回転され、描画パタン拡大縮小部５０４で拡大または縮小され、描画パタン短縮部５１０で長さを短くされた描画パタンを、座標値検出部５０２で検出された座標位置に順次描画する。なお、描画にあたっては、各サンプリング点の間に補間用の描画パタンを描画することにより、間の隙間を埋める処理をおこなう。このとき、単に、相似形の描画パタンを使用して描画をおこなう場合には、各サンプリング点を結ぶ直線を構成する点の位置に描画パタンのホットスポットが重なるように補間パタンを描画していけばよい。しかしながら、毛筆描画装置１００で採用する描画モデルは、筆圧や筆の進行方向によって描画パタンの形状が変化するため、筆先がサンプリング点間を結ぶ直線よりも長い軌跡を描く場合があり、単純な補間処理では、所々隙間があいてしまい、滑らかに補間することができない。
【００９１】
従って、描画部は、各サンプリング点での描画パタンを形成する多角形の頂点同士を結ぶ直線の中で最長の直線の長さを基に補間点数を求め、各補間点において筆圧と進行方向を徐々に変化させてできた描画パタンを描画していく処理もおこなう。
【００９２】
丸筆の場合は、筆の根元部分を示す円周上の真中にあたる点同士と、筆先を示す台形の各頂点間同士の直線距離を求め、平筆の場合は、筆先を示す台形の各頂点間同士の直線距離を求める。これらの頂点間同士で距離の一番長い直線の長さから補間点数を求める。具体的には、基準直線の始端座標を（ｘ１，　ｙ１）、終端座標を（ｘ２，　ｙ２）とすると、｜ｘ２−ｘ１｜≧｜ｙ２−ｙ１｜の場合は補間点数を｜ｘ２−ｘ１｜とし、｜ｘ２−ｘ１｜＜｜ｙ２−ｙ１｜の場合は補間点数を｜ｙ２−ｙ１｜とする。なお、座標値は整数値とする。
【００９３】
描画部５１１は、このようにして求めた補間点数により、各補間点の座標を計算し、各補間点での描画パタンのホットスポットが各サンプリング点を結ぶ直線上をたどるように描画していく。なお、描画パタンの各頂点を結ぶ線の軌跡は現実の描画では曲線を描くことになるため、補間点数を１．２〜１．５倍した補間点数を使用してもよい。補間中の筆圧、回転角度など変数の変化量は、補間をおこなう２点間での各変数の差分を補間数で割ったものを使用する。
【００９４】
毛筆描画装置１００は、描画部５１１の描画処理により質感の高い毛筆描画を可能とする。描画部５１１は、たとえば、毛筆描画ソフト４４２と、ＲＡＭ４０３と、ＣＰＵ４０１と、グラフィックスカード４０５と、表示装置１０４などによりその機能を実現することができる。
【００９５】
（毛筆描画装置１００の機能的構成：描画パタン自体の表現に関する機能的構成）
つぎに、毛筆描画装置１００の機能的構成のうち、特に描画パタン自体の表現に関する機能的構成について説明する。現実の毛筆描画では、毛筆を構成する毛の束や、墨汁の量、墨汁のにじみ易さ分離し易さなどの複数の要因が絡み合って毛筆独特の描画質感（かすれ、にじみ）を形成する。毛筆描画装置１００では、この描画質感を描画パタンの内部画像を変化させることにより表現する。
【００９６】
図１１は、本実施の形態の毛筆描画装置のうち描画パタンの内部画像を変化させる機能的構成の一例を示した説明図である。毛筆描画装置１００は、描画パタン内の表現を変化させる機能的構成として、濃淡画像調整部５１２と、停留判定部５１３と、平滑化部５１４と、停留回数計数部５１５と、平滑化制御部５１６と、を有する。ここではまず、描画パタン内部の一般的な濃淡画像について説明し、続いて各機能的構成について説明する。
【００９７】
図１２は、毛筆描画装置１００で採用する描画パタンと描画パタン内部の濃淡画像の一例を示した図である。濃淡や隙間のあいた描画パタンを用いることによって、毛筆１本１本の軌跡を反映した質感の高い描画が可能となる。描画パタンの生成方法としては、たとえば、中心から離れるにつれて徐々に薄くなっていく点パタンをランダムに描画パタン内に振る方法が挙げられる。具体的には、次のような点パタンを用いることができる。
Ｐ_ｘｙ＝　ａ・Ｄ_ｘｙ ^２　　　　　　　　　　　（０≦Ｐ_ｘｙ≦２５５）
（但し、Ｐ_ｘｙ＞２５５の場合はＰ_ｘｙ　＝２５５）
ここで、
Ｐ_ｘｙ　　　　　ピクセルの輝度（色値）
Ｄ_ｘｙ　　　　　中心点とそのピクセルとの距離
ａ　　　　　　広がりを調整するための係数
描画パタンは、点パタンの係数ａの値を調整することで、隙間の量を調整可能としている。
【００９８】
描画パタンの生成方法は、これ以外にも、たとえば、乱数により適当な個数のランダムな点を生成し、描画モードに応じて平滑化フィルタでこの点をぼかし、描画パタンが薄くならないように輝度レベルの補正を行って得てもよい。
【００９９】
なお、平滑化フィルタは、ある中心ピクセル（注目画素）と近傍のピクセルに注目し、指定された隣接範囲の色を平均化するという処理フィルタである。なお、矩形のフィルタを使用すると、四角いボケ方をするので、注目画素からの距離によって異なる重みをつけて、丸いボケ方をするようにしてもよい。
【０１００】
以降では、点パタンや平滑化フィルタを施され、ぼかしやボケの入った単位画像を濃淡画像と称することする。濃淡画像を調整することにより、毛筆独特のかすれやにじみを質感良く再現できる。
【０１０１】
まず、かすれを表現可能とする機能部について説明する。濃淡画像調整部５１２は、圧力検知部５０３で検出された圧力と距離間隔算出部５０７で判定された座標値の距離間隔に従って、濃淡画像の個数と大きさと濃淡を調整する。なお、使用の態様によっては、圧力のみに依存させる態様であってもよいし、距離間隔のみに依存させる態様であってもよい。また、個数のみを調整する態様であってもよいし大きさのみを調整する態様であってもよいし濃淡のみを調整する態様であってもよい。また、個数、大きさ、濃淡のうち２つを調整する態様であってもよい。
【０１０２】
毛筆描画装置１００では、計算処理負担を軽減するため、たとえば、点のサイズを大中小と３段階に限定し、輝度レベル補正の際のパラメータ調整を併用することにより、見かけ上連続的に隙間の量を調整できるようにしている。濃淡画像の調整は、描画モード選択時の初期段階に決定し、描画中に動的に変化させるものとする。濃淡画像調整部５１２による調整により、筆圧やタブレットペン１０３の速度によって自動的に隙間量を増減させることが可能となる。これにより、質感の高いかすれ表現が可能となる。濃淡画像調整部５１２は、たとえば、毛筆描画ソフト４４２と、ＲＡＭ４０３と、ＣＰＵ４０１などによりその機能を実現することができる。
【０１０３】
つぎに、にじみを表現する機能部について説明する。停留判定部５１３は、座標値検出部５０２で検出された座標値に基づいてタブレットペン１０３が停留しているか否かを判定する。平滑化部５１４は、停留判定部５１３でタブレットペン１０３が停留していると判断された場合に、描画パタンに平滑化処理を施す。停留回数計数部５１５は、停留判定部５１３でタブレットペン１０３が同一場所に停留していると判定された回数を計数する。平滑化制御部５１６は、停留回数計数部５１５で計数された回数に従って、平滑化部５１４を制御して平滑化処理の拡散パラメータを大きくする。
【０１０４】
現実の毛筆描画では、墨と水が分離しやすいような墨汁（例えば薄い墨）を筆に充分染み込ませて描画した場合に、特に停留点でにじみが見られる。毛筆描画装置１００では、タブレットペン１０３の停留時に停留時間に従って、拡散係数を大きくした平滑化フィルタを描画パタンに施し描画することにより、にじみを質感高く表現可能としている。にじみの再現については平滑化処理を採用するが、このとき、輝度補正をしないことにより、徐々に濃度が淡くなる様子を簡便に表現可能となる。図１３は、描画パタンに平滑化処理を順次施し、にじみが伝播する様子を示した図である。なお、徐々に拡散係数を増やしていく代わりに、前回使用した描画パタンを記憶しておき、それに重ねて平滑化処理を行った描画パタンを使用することによってもにじみの伝播を表現できる。
【０１０５】
平滑化部５１４と平滑化制御部５１６は、たとえば、毛筆描画ソフト４４２と、ＲＡＭ４０３と、ＣＰＵ４０１などによりその機能を実現することができる。停留回数計数部５１５は、たとえば、タブレット板１０２と、ドライバソフト４４３と毛筆描画ソフト４４２などによりその機能を実現することができる。
【０１０６】
描画部５１１は、描画パタン内の濃淡画像を変化させるこれらの各機能部の処理を経て決定ないし調整された描画パタンを、順次タブレットペン１０３の入力した座標位置に描画する。なお、毛筆描画装置１００は、墨汁を使った毛筆書画を表示装置１０４に質感高く再現するが、このほか、同様のアルゴリズムを用いて水彩筆や油彩筆による描画を再現することができる。特に、油彩筆を再現する場合には描画パタンにエンボスフィルタを施し、陰影をつけてもよい。図１４は、陰影パタンと描画例を示した図である。このうち、図１４（ａ）は、処理前の描画パタンであり、図１４（ｂ）は、エンボスフィルタを施した後の描画パタンであり、図１４（ｃ）は、描画例を示している。
【０１０７】
（毛筆描画装置１００の描画サンプル）
つぎに毛筆描画装置１００の描画例を示す。図１５は、毛筆描画装置の描画例を示した図である。図示したように、「とめ」「はね」「はらい」「かえし」など、現実の毛筆描画と同等の描画表現が可能となっていることが分かる。特に、タブレットペン１０３が座標の入力を開始したところと、座標の入力が終了したところの質感が極めて良く再現されていることが確認できる。
【０１０８】
図１６は、各種の描画モードによる毛筆描画例を示した図である。図１７は、図１６に示した各種の描画モードのパラメータを表示した図表である。図示したように、丸筆では、普通筆、ベタ筆、渇筆、薄墨筆の各描画モードを表現し、平筆では、水彩筆や油彩筆の描画モードを表現している。パラメータを適切に設定することにより、各種の描画表現が可能となっていることが分かる。
【０１０９】
毛筆描画装置１００は、消しゴムモードも備える。消しゴムモードとは、タブレットペン１０３の消しゴム部１３２が座標入力面１２１に座標を入力しているときに、その軌跡に沿って、なぞられた部分の線画を消去するモードをいう。消しゴムモードにより、コンピュータシステムのアンドゥー機能とはまた異なる描画質感を実現できる。なお、消しゴムモードは、タブレットペン１０３と連動しているので、従来のように複数回のアイコンクリックやプルダウン選択などにより実現されていた消しゴムモード選択のような煩雑さを解消し、毛筆描画装置１００の操作性を向上させることが可能となる。
【０１１０】
（毛筆描画装置の処理流れ）
つぎに、毛筆描画装置１００の処理流れについて説明する。図１８は、毛筆描画装置１００の処理流れの一例について説明したフローチャートである。毛筆描画装置１００は、まず、描画モードを決定する（ステップＳ６０１）。具体的には、描画パタンと描画パタンの描画中の制御パラメータを決定する（図１７参照）。
【０１１１】
続いて、タブレットペン１０３が入力している座標の座標値を所定の時間間隔毎に検出すると共に、座標を入力しているときの圧力を検知する（ステップＳ６０２）。毛筆描画装置１００では、タブレット１５０を用いているので、タブレット１５０により座標および圧力に関する情報を検知することができる。つぎに、座標値の軌跡からタブレットペン１０３の移動方向を算出し、描画パタンの配向（筆先方向）を決定する（ステップＳ６０３）。決定に際しては、タブレットペン１０３の移動方向の正反対の方向にむけて所定の慣性をもって配向する。具体的には、タブレットペン１０３の移動速度が小さくなるに従って回転角度の回転量を小さくする処理をおこなう。
【０１１２】
続いて、入力された座標の方向が急転回したかを判定し（ステップＳ６０４）、急転回したと判定された場合には、描画パタンの長さ部分を小さくする処理をおこなう（ステップＳ６０５）。ステップＳ６０３、ステップＳ６０４およびステップＳ６０５を経ることにより、描画している文字のカド部分や折り返し部分に不自然な突起が発現せず、自然な毛筆描画質感を得ることができる。
【０１１３】
最後に、各サンプリング点で順次描画パタンを描画していく（ステップＳ６０６）。サンプリング点上に描画していく描画パタンは、ステップＳ６０１で決定した描画モードの初期設定の画像に基づき、各種条件に従って適宜変化させる。具体的には、タブレットペン１０３の筆圧や速度に従って、描画パタンを構成する濃淡画像の個数や大きさや濃淡を調整する。特に、薄墨筆モードの場合はタブレットペン１０３の停留時間に従って平滑化処理を順次施し、墨滴がにじんでいくような描画パタンを描画する。
【０１１４】
なお、以上の各機能部はコンピュータプログラムとして実現できる。すなわち、コンピュータシステムを各機能部を実現させる手段として機能させることができる。図１９〜図２４は、コンピュータプログラムの処理結果を表示装置１０４に表示させた場合の画面構成例を示した図である。画面構成のうち、「ファイル」メニュー７０１は、ファイルのオープン、クローズ、新規作成などの基本動作をおこなうメニューである。また、「筆」メニュー７０２は、図１９〜図２４に示した各描画モード、消しゴムモード、および、後述するカスタム設定をおこなうメニューである。
【０１１５】
また、「背景」メニューは、下地を設定するメニューであり、たとえば、半紙（無地）、画用紙、キャンバス地を設定することができる。図２５は、画用紙の下地例を示した図であり、図２６は、キャンバス地の下地例を示した図である。図示したようにそれぞれの下地例では無地である半紙と異なる一定の濃淡画像が形成されており、描画パタンが重ね合わされることにより、下地を考慮した描画質感を得ることができる。現実の描画では、水彩画や油彩画で下地の凹凸が表にでる場合があるが、毛筆描画装置１００では、たとえば、キャンバス地に水墨画を描くなど、現実の組み合わせでは採用されない、コンピュータシステムならではの描画質感を得ることも可能となる。
【０１１６】
「色選択」メニュー７０４は、各種の描画色を選択するメニューである。従って、毛筆書画においては、黒以外の従来にない水墨画表現が可能となる。「消去」メニュー７０５は、描画画面７０６上に描画した文字や線図を総て消去するメニューである。
【０１１７】
つぎに、「筆」メニュー７０２の特性（Ｐ）について説明する。毛筆描画の各種パラメータのカスタム設定を可能にする。図２７は、描画パタンのサイズをカスタマイズする設定画面の一例を示した図である。図示したように、描画パタンの長さ、根元の幅、先端部の幅を変更可能としている。図２８は、濃淡画像などをカスタマイズする設定画面の一例を示した図である。図示したように、テクスチャパタンと描画パタンの合成比率、点密度の補正量、慣性ｍの調整、タブレットペン１０３の転回を判定する基準値を変更可能としている。なお、テクスチャパタンと描画パタンの合成比率とは、下地の凹凸や濃淡（テクスチャ）と描画パタンの濃淡の合成比率を表す。
【０１１８】
図２９は、インク（墨汁）をカスタマイズする設定画面の一例を示した図である。図示したように、インクの量、筆圧によるかすれの変化の有無、筆の早さによるかすれの変化の有無、速度によるかすれの量、にじみの量を変更可能としている。図３０は、濃度とコントラストをカスタマイズする設定画面の一例を示した図である。図３１は、染み込みの量と遅延制御をカスタマイズする設定画面の一例を示した図である。なお、遅延制御とは、パソコンの描画能力が低くて描画が追いつかない状態が発生したときに、自動的に補間を粗くし、ペンの動きに描画が追従しなくなるのを防止する機能を実現する制御をいう。
【０１１９】
以上説明した各機能部を適宜プログラム化し、タブレット１５０を備えるコンピュータシステムにインストールすることで、コンピュータを毛筆描画装置として作動させることができる。なお、プログラムの流通態様は、ＣＤ−ＲＯＭなどの記録媒体に限られずインターネットのような電気回線を通じて流通させることもできる。
【０１２０】
【発明の効果】
上記説明したように、本発明の毛筆描画装置（請求項１）は、座標入力面と座標入力面に対して座標を入力する座標入力手段と、を有するタブレットを含み、描画の基本形状である描画パタンの軌跡に従って描画をおこなう毛筆描画装置であって、座標値検出手段が、座標入力手段により入力された座標の座標値を所定の時間間隔毎に検出しと、圧力検知手段が、座標入力手段によって座標入力面に対して座標が入力しているときの圧力を検知し、拡大縮小手段が、圧力検知手段により検知された圧力に従って描画パタンの大きさを拡大または縮小し、移動方向算出手段が、座標値検出手段により順次検出された座標値に基づいて座標入力手段の移動方向を算出し、描画パタン回転手段が、移動方向算出手段により算出された移動方向の反対方向に描画パタンの筆先部分が向くように当該描画パタンを回転させ、距離間隔算出手段が、座標値検出手段により順次検出された座標値の隣り合う距離間隔を算出し、回転制御手段が、距離間隔算出手段により算出された座標値の距離間隔に基づいて描画パタン回転手段を制御して描画パタンの回転量を小さくし、描画手段が、描画パタン回転手段または回転制御手段により回転され拡大縮小手段により拡大または縮小された描画パタンを、座標値検出手段により検出された座標位置に順次描画するので、描画する文字や線図の「カド」の部分で描画パタンが緩やかに方向転換し、これにより、タブレットを用いて自然な毛筆描画を質感良く再現可能となる。
【０１２１】
また、本発明の毛筆描画装置（請求項２）は、請求項１に記載の毛筆描画装置において、転回判定手段が、移動方向算出手段により算出された移動方向が急転回したか否かを判定し、パタン短縮手段が、転回判定手段によって移動方向が急転回したと判定された場合に、所定の描画個数分または所定の描画距離分だけ描画パタンの長さを短くし、描画手段が、描画パタン回転手段および回転制御手段により回転され、拡大縮小手段により拡大または縮小され、パタン短縮手段により長さを短くされた描画パタンを、座標値検出手段により検出された座標位置に順次描画するので、「はね」などのように、急峻な折り返し描画において、描画パタンによる不要な突起描画を防止し、これにより、タブレットを用いて自然な毛筆描画を質感良く再現可能となる。
【０１２２】
また、本発明の毛筆描画装置（請求項３）は、請求項１または２に記載の毛筆描画装置において、描画パタンを構成する画素のうち所定の画素を中心として距離が離れるにつれ描画色が淡くなる複数の濃淡画像により描画パタンを構成し、濃淡画像調整手段が、圧力検知手段により検出された圧力に従って、および／または、距離間隔算出手段により判定された座標値の距離間隔に従って、濃淡画像の個数および／または濃淡画像の大きさおよび／または前記濃淡画像の濃淡を調整し、描画手段が、さらに、濃淡画像調整手段により調整された描画パタンを描画するので、かすれ表現が可能となり、これにより、タブレットを用いて自然な毛筆描画を質感良く再現できる。
【０１２３】
また、本発明の毛筆描画装置（請求項４）は、請求項３に記載の毛筆描画装置において、描画パタンを、描画パタン内に無秩序に振った黒点画像に対し、平滑化フィルタを施して得られた画像により構成したので、かすれ表現を簡便に構成可能な描画パタンを用いることができ、これにより、タブレットを用いて自然な毛筆描画を質感良く再現できる。
【０１２４】
また、本発明の毛筆描画装置（請求項５）は、請求項１〜４のいずれか一つに記載の毛筆描画装置において、停留判定手段が、座標値検出手段により検出された座標値に基づいて座標入力手段が停留しているか否かを判定し、平滑化手段が、停留判定手段によって座標入力手段が停留していると判断された場合に、描画パタンに平滑化処理を施し、描画手段が、さらに、平滑化手段により平滑化された描画パタンを描画するので、にじみ表現が可能となり、これにより、タブレットを用いて自然な毛筆描画を質感良く再現できる。
【０１２５】
また、本発明の毛筆描画装置（請求項６）は、請求項５に記載の毛筆描画装置において、停留回数計数手段が、停留判定手段によって座標入力手段が同一場所に停留していると判定された回数を計数し、平滑化制御手段が、停留回数計数手段により計数された回数に従って、平滑化手段を制御して平滑化処理の拡散パラメータを大きくし、描画手段が、さらに、平滑化制御手段の制御を受けて平滑化された描画パタンを描画するので、動的なにじみ表現が可能となり、これにより、タブレットを用いて自然な毛筆描画を質感良く再現できる。
【０１２６】
また、本発明の毛筆描画プログラム（請求項７）は、座標入力面と座標入力面に対して座標を入力する座標入力手段と、を有するタブレットからの出力信号を用いて、描画の基本形状である描画パタンをその軌跡に従って描画させるプログラムであって、コンピュータを、座標入力手段により入力された座標の座標値を所定の時間間隔毎に検出する座標値検出手段と、座標入力手段が座標入力面に対して座標を入力しているときの圧力を検知する圧力検知手段と、圧力検知手段により検知された圧力に従って描画パタンの大きさを拡大または縮小する拡大縮小手段と、座標値検出手段により順次検出された座標値に基づいて座標入力手段の移動方向を算出する移動方向算出手段と、移動方向算出手段により算出された移動方向の反対方向に描画パタンの筆先部分が向くように当該描画パタンを回転させる描画パタン回転手段と、座標値検出手段により順次検出された座標値の隣り合う距離間隔を算出する距離間隔算出手段と、距離間隔算出手段により算出された座標値の距離間隔に基づいて描画パタン回転手段を制御し、描画パタンの回転量を小さくする回転制御手段と、描画パタン回転手段または回転制御手段により回転され拡大縮小手段により拡大または縮小された描画パタンを、座標値検出手段により検出された座標位置に順次描画する描画手段として機能させるので、描画する文字や線図のカドの部分で描画パタンが緩やかに方向転換し、これにより、タブレットを用いて自然な毛筆描画を質感良く再現可能となる。
【０１２７】
また、本発明の毛筆描画プログラム（請求項８）は、請求項７に記載の毛筆描画プログラムにおいて、さらに、コンピュータを、移動方向算出手段により算出された移動方向が急転回したか否かを判定する転回判定手段と、転回判定手段により移動方向が急転回したと判定された場合に、所定の描画個数分または所定の描画距離分だけ描画パタンの長さを短くするパタン短縮手段として機能させ、描画手段として、描画パタン回転手段および回転制御手段により回転され、拡大縮小手段により拡大または縮小され、パタン短縮手段により長さを短くされた描画パタンを、座標値検出手段により検出された座標位置に順次描画させるので、「はね」などのように、急峻な折り返し描画において、描画パタンによる不要な突起描画を防止し、これにより、タブレットを用いて自然な毛筆描画を質感良く再現可能となる。
【０１２８】
また、本発明の毛筆描画プログラム（請求項９）は、請求項７または８に記載の毛筆描画プログラムにおいて、描画パタンを構成する画素のうち所定の画素を中心として距離が離れるにつれ描画色が淡くなる複数の濃淡画像により描画パタンを構成し、さらに、コンピュータを、圧力検知手段により検出された圧力に従って、および／または、距離間隔算出手段により判定された座標値の距離間隔に従って、濃淡画像の個数および／または濃淡画像の大きさおよび／または前記濃淡画像の濃淡を調整する濃淡画像調整手段として機能させ、描画手段として、さらに、濃淡画像調整手段により調整された描画パタンを描画するように機能させるので、かすれ表現が可能となり、これにより、タブレットを用いて自然な毛筆描画を質感良く再現できる。
【０１２９】
また、本発明の毛筆描画プログラム（請求項１０）は、請求項９に記載の毛筆描画プログラムにおいて、描画パタンを、描画パタン内に無秩序に振った黒点画像に対し、平滑化フィルタを施して得られた画像により構成したのでかすれ表現を簡便に構成可能な描画パタンを用いることができ、これにより、タブレットを用いて自然な毛筆描画を質感良く再現できる。
【０１３０】
また、本発明の毛筆描画プログラム（請求項１１）は、請求項７〜１０のいずれか一つに記載の毛筆描画プログラムにおいて、さらに、コンピュータを、座標値検出手段により検出された座標値に基づいて座標入力手段が停留しているか否かを判定する停留判定手段と、停留判定手段により座標入力手段が停留していると判断された場合に、描画パタンに平滑化処理を施す平滑化手段として機能させ、描画手段として、さらに、平滑化手段により平滑化された描画パタンを描画するように機能させるので、にじみ表現が可能となり、これにより、タブレットを用いて自然な毛筆描画を質感良く再現できる。
【０１３１】
また、毛筆描画プログラム（請求項１２）は、請求項１１に記載の毛筆描画プログラムにおいて、さらに、コンピュータを、停留判定手段により座標入力手段が同一場所に停留している回数を計数する停留回数計数手段と、停留回数計数手段により計数された回数に従って、平滑化手段を制御して平滑化処理の拡散パラメータを大きくする平滑化制御手段として機能させ、描画手段として、さらに、平滑化制御手段の制御を受けて平滑化された描画パタンを描画するように機能させるので、動的なにじみ表現が可能となり、タブレットを用いて自然な毛筆描画を質感良く再現できる。
【０１３２】
また、本発明の毛筆描画方法（請求項１３）は、座標入力面と座標入力面に対して座標を入力する座標入力手段と、を有するタブレットを含み、描画の基本形状である描画パタンの軌跡に従って描画をおこなう毛筆描画装置に適用する毛筆描画方法であって、座標値検出工程では、座標入力手段により入力された座標の座標値を所定の時間間隔毎に検出し、圧力検知工程では、座標入力工程で座標入力面に対して座標を入力しているときの圧力を検知し、拡大縮小工程では、圧力検知工程で検知された圧力に従って描画パタンの大きさを拡大または縮小し、移動方向算出工程では、座標値検出工程で順次検出された座標値に基づいて座標入力手段の移動方向を算出し、描画パタン回転工程では、移動方向算出工程で算出された移動方向の反対方向に描画パタンの筆先部分が向くように当該描画パタンを回転させ、距離間隔算出工程では、座標値検出工程で順次検出された隣り合う座標値の距離間隔を算出し、回転制御工程では、距離間隔算出工程で算出された座標値の距離間隔に基づいて描画パタン回転工程における回転処理を制御して描画パタンの回転量を小さくし、描画工程では、描画パタン回転工程または回転制御工程を経て回転され拡大縮小工程を経て拡大または縮小された描画パタンを、座標値検出工程で検出された座標位置に順次描画するので、描画する文字や線図のカドの部分で描画パタンが緩やかに方向転換し、これにより、タブレットを用いて自然な毛筆描画を質感良く再現可能となる。
【０１３３】
また、本発明の毛筆描画方法（請求項１４）は、請求項１３に記載の毛筆描画方法において、転回判定工程では、移動方向算出工程で算出された移動方向が急転回したか否かを判定し、パタン短縮工程では、転回判定工程で移動方向が急転回したと判定された場合に、所定の描画個数分または所定の描画距離分だけ描画パタンの長さを短くし、描画工程では、描画パタン回転工程および回転制御工程を経て回転され、拡大縮小工程を経て拡大または縮小され、パタン短縮工程を経て長さを短くされた描画パタンを、座標値検出工程で検出された座標位置に順次描画するので、「はね」などのように、急峻な折り返し描画において、描画パタンによる不要な突起描画を防止し、これにより、タブレットを用いて自然な毛筆描画を質感良く再現可能となる。
【０１３４】
また、本発明の毛筆描画方法（請求項１５）は、請求項１３または１４に記載の毛筆描画方法において、描画パタンを構成する画素のうち所定の画素を中心として距離が離れるにつれ描画色が淡くなる複数の濃淡画像により描画パタンを構成し、濃淡画像調整工程では、圧力検知工程で検出された圧力に従って、および／または、距離間隔算出工程で判定された座標値の距離間隔に従って、濃淡画像の個数および／または濃淡画像の大きさおよび／または前記濃淡画像の濃淡を調整し、描画工程では、さらに、濃淡画像調整行程を経て調整された描画パタンを描画するので、かすれ表現が可能となり、これにより、タブレットを用いて自然な毛筆描画を質感良く再現できる。
【０１３５】
また、本発明の毛筆描画方法（請求項１６）は、請求項１３、１４または１５に記載の毛筆描画方法において、停留判定工程では、座標値検出行程で検出された座標値に基づいて座標入力手段が停留しているか否かを判定し、平滑化工程では、停留判定工程で座標入力手段が停留していると判断された場合に、描画パタンに平滑化処理を施し、描画工程では、さらに、平滑化工程を経て平滑化された描画パタンを描画するので、にじみ表現が可能となり、これにより、タブレットを用いて自然な毛筆描画を質感良く再現できる。
【０１３６】
また、本発明の毛筆描画方法（請求項１７）は、請求項１６に記載の毛筆描画方法において、停留回数計数工程では、停留判定工程で座標入力手段が同一場所に停留している回数を計数し、平滑化制御工程では、停留回数計数行程で計数された回数に従って、平滑化工程における平滑化処理を制御して当該平滑化処理の拡散パラメータを大きくし、描画工程では、さらに、平滑化制御工程の制御を受けて平滑化された描画パタンを描画するので、動的なにじみ表現が可能となり、これにより、タブレットを用いて自然な毛筆描画を質感良く再現できる。
【図面の簡単な説明】
【図１】本発明の毛筆描画装置の概観構成の一例を示した説明図である。
【図２】タブレット（タブレット板とタブレットペン）の構成例を示した説明図である。
【図３】座標入力面と表示装置とを一体的に構成した液晶ペンタブレットの外観構成を示した図である。
【図４】本発明の毛筆描画装置のハードウェア構成の一例を示した説明図である。
【図５】本実施の形態の毛筆描画装置のうち毛筆描画の軌跡を律する機能的構成の一例を示した説明図である。
【図６】描画パタンと筆圧（圧力値）の関係を示した説明図である。
【図７】描画パタンを作成するための各変数を定義する説明図である。
【図８】描画パタンの向きθとタブレットペンの移動方向の関係を示す。
【図９】カドにおける不自然な突起描画と、慣性を制御した場合の描画パタンの向きを示した描画概念図である。
【図１０】タブレットペンを急転回させたときに出現する不自然な突起描画の例を示した図である。
【図１１】本実施の形態の毛筆描画装置のうち描画パタン内の表現を変化させる機能的構成の一例を示した説明図である。
【図１２】毛筆描画装置で採用する描画パタンと描画パタン内部の濃淡画像（拡大図）の一例を示した図である。
【図１３】描画パタンに平滑化処理を順次施し、にじみが伝播する様子を示した図である。
【図１４】陰影パタンと描画例を示した図である。
【図１５】毛筆描画装置の描画例を示した図である。
【図１６】各種の描画モードによる毛筆描画例を示した図である。
【図１７】図１６に示した各種の描画モードのパラメータを表示した図表である。
【図１８】毛筆描画装置の処理流れについて説明したフローチャートである。
【図１９】コンピュータプログラムの処理結果を表示装置に表示させた場合の画面構成例を示した図である。
【図２０】コンピュータプログラムの処理結果を表示装置に表示させた場合の画面構成例を示した図である。
【図２１】コンピュータプログラムの処理結果を表示装置に表示させた場合の画面構成例を示した図である。
【図２２】コンピュータプログラムの処理結果を表示装置に表示させた場合の画面構成例を示した図である。
【図２３】コンピュータプログラムの処理結果を表示装置に表示させた場合の画面構成例を示した図である。
【図２４】コンピュータプログラムの処理結果を表示装置に表示させた場合の画面構成例を示した図である。
【図２５】画用紙の下地例を示した図である。
【図２６】キャンバス地の下地例を示した図である。
【図２７】描画パタンのサイズをカスタマイズする設定画面の一例を示した図である。
【図２８】濃淡画像などをカスタマイズする設定画面の一例を示した図である。
【図２９】インク（墨汁）をカスタマイズする設定画面の一例を示した図である。
【図３０】濃度とコントラストをカスタマイズする設定画面の一例を示した図である。
【図３１】染み込みの量と遅延制御をカスタマイズする設定画面の一例を示した図である。
【符号の説明】
１００　　　　　　　　毛筆描画装置
１０１　　　　　　　　本体装置
１０２　　　　　　　　タブレット板
１０３　　　　　　　　タブレットペン
１０４　　　　　　　　表示装置
１０５　　　　　　　　キーボード
１０６　　　　　　　　マウス
１２１　　　　　　　　座標入力面
１２２　　　　　　　　ペンスタンド
１２３　　　　　　　　伝送線
１３１　　　　　　　　ペン先部
１３２　　　　　　　　消しゴム部
１３３，１３４　　　　　　　サイドスイッチ
１５０　　　　　　　　タブレット
４０１　　　　　　　　ＣＰＵ
４０２　　　　　　　　ＲＯＭ
４０３　　　　　　　　ＲＡＭ
４０４　　　　　　　　ハードディスク（ＨＤ）
４０５　　　　　　　　グラフィックスカード
４４１　　　　　　　　ＯＳ
４４２　　　　　　　　毛筆描画ソフト
４４３　　　　　　　　ドライバソフト
５０１　　　　　　　　座標入力部
５０２　　　　　　　　座標値検出部
５０３　　　　　　　　圧力検知部
５０４　　　　　　　　描画パタン拡大縮小部
５０５　　　　　　　　移動方向算出部
５０６　　　　　　　　描画パタン回転部
５０７　　　　　　　　距離間隔算出部
５０８　　　　　　　　回転制御部
５０９　　　　　　　　転回判定部
５１０　　　　　　　　描画パタン短縮部
５１１　　　　　　　　描画部
５１２　　　　　　　　濃淡画像調整部
５１３　　　　　　　　停留判定部
５１４　　　　　　　　平滑化部
５１５　　　　　　　　停留回数計数部
５１６　　　　　　　　平滑化制御部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a brush drawing apparatus, a brush drawing program, and a brush drawing method, and more particularly to a brush drawing apparatus including a tablet having a coordinate input surface and coordinate input means for inputting coordinates with respect to the coordinate input surface, and a brush drawing. The present invention relates to a program and a brush drawing method.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known one that realizes various drawing functions using a computer. For example, it has been possible to draw outlines of lines and figures on a computer screen, or to paint, overwrite, and superimpose using each color. In addition, in order to more intuitively operate, coordinate input may be performed using a so-called tablet. The use of a tablet enables more intuitive operation than when a mouse is used, and a drawing operation similar to drawing with a real writing tool or drawing tool such as a paintbrush or pastel has been realized on a computer.
[0003]
In particular, as a technique for realizing a drawing expression specialized for writing with a brush and a handwriting, for example, Japanese Patent Application Laid-Open No. Hei 6-222879, “Handwriting Display Method and Handwriting Display Device”, and Japanese Patent Application Laid-Open No. 9-198823, Font creation software ", JP-A-2000-330980," Handwritten character output device and program recording medium therefor ", Japanese Patent Publication No. Hei 6-79324," Method of generating brush strokes ", and JP 2916022," Method of drawing brush strokes " Etc. were known. Conventionally, such a technique has realized an expression similar to actual brushstroke drawing.
[Problems to be solved by the invention]
However, the conventional technique has the following problems.
In other words, the conventional brush drawing apparatus using a tablet merely replaces the mouse with a tablet and pursues hardware-like pseudo-characteristics, and does not reproduce the actual brush drawing with good texture.
[0004]
Specifically, there is a problem in that the reproducibility of the actual brushstroke texture such as blurring or blurring is low. In addition, in brush drawing, sharp folds are developed at the “kad” part of characters, but there is a problem that unnecessary and unnatural protrusions are drawn simply by electronically following the drawing pattern. Was. In other words, there is a problem that natural brush drawing cannot be realized with the conventional brush drawing.
[0005]
The present invention has been made in view of the above, and an object of the present invention is to enable a natural brushstroke drawing to be reproduced with good texture using a tablet.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a brush writing apparatus according to claim 1 includes a tablet having a coordinate input surface and coordinate input means for inputting coordinates with respect to the coordinate input surface. What is claimed is: 1. A brushstroke drawing device that draws in accordance with a locus of a certain drawing pattern, wherein a coordinate value detecting unit that detects a coordinate value of coordinates input by the coordinate input unit at predetermined time intervals; Pressure detecting means for detecting pressure when coordinates are input to the input surface; scaling means for enlarging or reducing the size of the drawing pattern according to the pressure detected by the pressure detecting means; Moving direction calculating means for calculating a moving direction of the coordinate input means based on the coordinate values sequentially detected by the value detecting means, and a moving direction calculated by the moving direction calculating means Drawing pattern rotating means for rotating the drawing pattern so that the brush tip portion of the drawing pattern faces in the opposite direction, distance interval calculating means for calculating adjacent distance intervals of coordinate values sequentially detected by the coordinate value detecting means, A rotation control unit that controls the drawing pattern rotation unit based on the distance interval of the coordinate values calculated by the distance interval calculation unit, and reduces a rotation amount of the drawing pattern; and the drawing pattern rotation unit or the rotation control unit. Drawing means for sequentially drawing the rotated drawing pattern enlarged or reduced by the scaling means at the coordinate position detected by the coordinate value detecting means.
[0007]
In other words, according to the first aspect of the invention, the direction of the drawing pattern is gradually changed at the portion of the character to be drawn or the corner of the diagram. In other words, the drawing pattern can be rotated with inertia.
[0008]
Further, in the brush-drawing device according to claim 2, in the brush-drawing device according to claim 1, a rotation determining unit that determines whether or not the moving direction calculated by the moving-direction calculating unit has suddenly rotated, Pattern shortening means for shortening the length of the drawing pattern by a predetermined drawing number or a predetermined drawing distance, when the turning direction determining means determines that the moving direction is suddenly turned, The drawing pattern rotated by the drawing pattern rotating unit or the rotation control unit, enlarged or reduced by the scaling unit, and reduced in length by the pattern shortening unit is detected by the coordinate value detecting unit. It is characterized in that drawing is performed sequentially at coordinate positions.
[0009]
That is, the invention according to claim 2 prevents unnecessary projection drawing by a drawing pattern in steep turn drawing, such as “splash”.
[0010]
According to a third aspect of the present invention, in the brush writing apparatus according to the first or second aspect, the drawing pattern is formed by a plurality of grayscale images in which the drawing color becomes lighter as the distance from the predetermined pixel is increased. The number of the grayscale images and / or the size and / or the size of the grayscale image according to the pressure detected by the pressure detection unit and / or the distance interval of the coordinate value determined by the distance interval calculation unit. The image processing apparatus further includes a gray-scale image adjusting unit that adjusts the gray scale of the gray-scale image, and the drawing unit further draws a drawing pattern adjusted by the gray-scale image adjusting unit.
[0011]
That is, the invention according to claim 3 enables a blurred expression.
[0012]
Further, in the brush-drawing apparatus according to the fourth aspect, in the brush-drawing apparatus according to the third aspect, the drawing pattern is obtained by applying a smoothing filter to a black point image randomly shaken in the drawing pattern. Characterized in that the image is composed of images.
[0013]
That is, the invention according to claim 4 uses a drawing pattern capable of easily forming a blurred expression.
[0014]
According to a fifth aspect of the present invention, in the brush writing apparatus according to any one of the first to fourth aspects, the coordinate input unit may be configured to execute the coordinate input unit based on the coordinate value detected by the coordinate value detection unit. A stop determination unit that determines whether the vehicle is stopped, and a smoothing unit that performs a smoothing process on the drawing pattern when the stop determination unit determines that the coordinate input unit is stopped. And wherein the drawing means draws the drawing pattern smoothed by the smoothing means.
[0015]
That is, the invention according to claim 5 enables blur expression.
[0016]
Further, the brush drawing device according to claim 6 is a brush drawing device according to claim 5, wherein the stop determination unit counts the number of times the coordinate input unit is stopped at the same place by the stop determination unit. A smoothing control means for controlling the smoothing means to increase a diffusion parameter of a smoothing process according to the number of times counted by the stop number counting means, wherein the drawing means further comprises: Under the control of the means, a smoothed drawing pattern is drawn.
[0017]
That is, the invention according to claim 6 enables dynamic blur expression.
[0018]
Further, a writing brush drawing program according to a seventh aspect of the present invention provides a drawing which is a basic shape of drawing by using an output signal from a tablet having a coordinate input surface and coordinate input means for inputting coordinates to the coordinate input surface. A program for drawing a pattern in accordance with the locus thereof, the program comprising: a computer for detecting coordinate values of coordinates input by the coordinate input means at predetermined time intervals; and Pressure detecting means for detecting pressure when coordinates are input to a surface, scaling means for expanding or reducing the size of the drawing pattern according to the pressure detected by the pressure detecting means, and the coordinate value Moving direction calculating means for calculating the moving direction of the coordinate input means based on the coordinate values sequentially detected by the detecting means, and calculating by the moving direction calculating means Drawing pattern rotation means for rotating the drawing pattern so that the tip of the drawing pattern is directed in the direction opposite to the moving direction, and a distance for calculating an adjacent distance between coordinate values sequentially detected by the coordinate value detecting means. An interval calculation unit, a rotation control unit that controls the drawing pattern rotation unit based on the distance interval of the coordinate values calculated by the distance interval calculation unit, and reduces a rotation amount of the drawing pattern; and the drawing pattern rotation unit or The drawing pattern rotated by the rotation control unit and enlarged or reduced by the enlargement / reduction unit is caused to function as a drawing unit for sequentially drawing at a coordinate position detected by the coordinate value detection unit.
[0019]
That is, in the invention according to claim 7, the direction of the drawing pattern is gradually changed at the portion of the character to be drawn or the portion of the line diagram.
[0020]
According to an eighth aspect of the present invention, in the writing brush drawing program according to the seventh aspect, the computer further determines whether or not the moving direction calculated by the moving direction calculating means has suddenly turned. Turning determining means, and functioning as pattern shortening means for shortening the length of the drawing pattern by a predetermined number of drawing or a predetermined drawing distance when the turning determining means determines that the moving direction is suddenly turned. A drawing pattern rotated by the drawing pattern rotation unit or the rotation control unit, enlarged or reduced by the scaling unit, and reduced in length by the pattern shortening unit as the drawing unit; The function is such that the drawing is sequentially performed at the coordinate positions detected by (1).
[0021]
In other words, the invention according to claim 8 prevents unnecessary projection drawing by a drawing pattern in steep turn-drawing such as “splash”.
[0022]
According to a ninth aspect of the present invention, there is provided a brushstroke drawing program according to the seventh or eighth aspect, wherein a drawing pattern is formed by a plurality of grayscale images in which a drawing color becomes lighter as the distance from a predetermined pixel is increased. Further, the computer may be configured to control the number of the grayscale images and / or the number of the grayscale images according to the pressure detected by the pressure detection unit and / or the distance interval of the coordinate value determined by the distance interval calculation unit. A function of adjusting a size and / or a density of the grayscale image; and a function of drawing as a drawing pattern adjusted by the grayscale image adjusting means. I do.
[0023]
That is, the ninth aspect of the present invention enables a faint expression.
[0024]
According to a tenth aspect of the present invention, there is provided the brushstroke drawing program according to the ninth aspect, wherein the drawing pattern is obtained by applying a smoothing filter to a black spot image randomly shaken in the drawing pattern. Characterized in that the image is composed of images.
[0025]
That is, the invention according to claim 10 uses a drawing pattern capable of easily forming a blurred expression.
[0026]
According to an eleventh aspect of the present invention, there is provided a brushstroke drawing program according to any one of the seventh to tenth aspects, further comprising the step of: causing a computer to execute the program based on the coordinate values detected by the coordinate value detecting means. A stop determining unit that determines whether the coordinate input unit is stopped; and a smoothing unit that performs a smoothing process on the drawing pattern when the stop input unit determines that the coordinate input unit is stopped. And a function to render the drawing pattern smoothed by the smoothing means as the drawing means.
[0027]
That is, the invention according to claim 11 enables blur expression.
[0028]
According to a twelfth aspect of the present invention, there is provided the brush-drawing program according to the eleventh aspect, further comprising: causing the computer to count the number of times the coordinate input unit is parked at the same place by the stationary-state judging unit. The number of stops counting means, according to the number of times counted by the number of stops counting means, controls the smoothing means to function as a smoothing control means to increase the diffusion parameter of the smoothing process, as the drawing means, further, Under the control of the smoothing control means, it is made to function to draw a smoothed drawing pattern.
[0029]
That is, the invention according to claim 12 enables dynamic blur expression.
[0030]
A brushstroke drawing method according to a thirteenth aspect includes a tablet having a coordinate input surface and coordinate input means for inputting coordinates with respect to the coordinate input surface, and performs drawing in accordance with a locus of a drawing pattern that is a basic shape of drawing. A brush-drawing method applied to a brush-drawing device that performs a coordinate value detecting step of detecting a coordinate value of a coordinate input by the coordinate input means at predetermined time intervals; and A pressure detection step of detecting pressure when coordinates are input to the surface; a scaling step of expanding or reducing the size of the drawing pattern according to the pressure detected in the pressure detection step; A moving direction calculating step of calculating a moving direction of the coordinate input means based on the coordinate values sequentially detected in the detecting step, and a direction opposite to the moving direction calculated in the moving direction calculating step A drawing pattern rotating step of rotating the drawing pattern so that the brush tip portion of the drawing pattern faces, a distance interval calculating step of calculating adjacent distance intervals of the coordinate values sequentially detected in the coordinate value detecting step, and the distance interval A rotation control step of controlling the rotation processing in the drawing pattern rotation step based on the distance interval of the coordinate values calculated in the calculation step to reduce the rotation amount of the drawing pattern; and the drawing pattern rotation step or the rotation control step. A drawing step of sequentially drawing drawing patterns rotated and enlarged or reduced through the enlargement / reduction step at the coordinate positions detected in the coordinate value detection step.
[0031]
That is, in the invention according to the thirteenth aspect, the drawing pattern changes direction gradually at the portion of the character to be drawn or the corner of the line diagram.
[0032]
In addition, the brush stroke drawing method according to claim 14 is, in the brush stroke drawing method according to claim 13, a turning determination step of determining whether or not the movement direction calculated in the movement direction calculation step has suddenly turned, A pattern shortening step of shortening the length of the drawing pattern by a predetermined number of drawings or a predetermined drawing distance when it is determined in the turning determination step that the moving direction is suddenly turned; In the coordinate pattern detecting step, a drawing pattern rotated through the drawing pattern rotation step or the rotation control step, enlarged or reduced through the enlargement / reduction step, and reduced in length through the pattern reduction step is used in the coordinate value detection step. Characters are sequentially drawn at the detected coordinate positions.
[0033]
In other words, the invention according to claim 14 prevents unnecessary projection drawing by a drawing pattern in steep turn-drawing such as “splash”.
[0034]
Further, in the brushstroke drawing method according to claim 15, in the brushstroke drawing method according to claim 13 or 14, the drawing pattern is configured by a plurality of grayscale images in which the drawing color becomes lighter as the distance from the predetermined pixel is increased. According to the pressure detected in the pressure detecting step and / or according to the distance interval of the coordinate value determined in the distance interval calculating step, the number of the gray image and / or the size and / or the size of the gray image The method further includes a gradation image adjustment step of adjusting the gradation of the gradation image, wherein the drawing step further includes drawing a drawing pattern adjusted through the gradation image adjustment step.
[0035]
In other words, the invention according to claim 15 enables blurred expression.
[0036]
In a brush writing method according to a sixteenth aspect, in the brush writing method according to the thirteenth, fourteenth, or fifteenth aspect, the coordinate input means stops based on the coordinate values detected in the coordinate value detection step. A stop determination step of determining whether or not the coordinate input means is determined to be stopped in the stop determination step, including a smoothing step of performing a smoothing process on the drawing pattern, In the drawing step, a drawing pattern smoothed through the smoothing step is drawn.
[0037]
That is, the invention according to claim 16 enables blur expression.
[0038]
Further, in the brush-drawing method according to claim 17, in the brush-drawing method according to claim 16, a stop number counting step of counting the number of times the coordinate input means stops at the same place in the stop determination step. And a smoothing control step of controlling a smoothing process in the smoothing process to increase a diffusion parameter of the smoothing process in accordance with the number counted in the number-of-stops counting process. And drawing a drawing pattern smoothed under the control of the smoothing control step.
[0039]
That is, the invention according to claim 17 enables dynamic blur expression.
[0040]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the present embodiment, the present invention is applied to a computer system, and its external configuration, hardware configuration, functional configuration, and processing flow will be sequentially described.
[0041]
(Brush writing device: external configuration)
FIG. 1 is an explanatory diagram showing an example of a general configuration of a brush writing apparatus according to the present invention. The brush drawing device 100 includes a main body device 101 that performs an operation related to a brush drawing process, a tablet board 102 having a coordinate input surface for receiving a coordinate input, and a tablet pen (stylus pen) 103 that inputs coordinates to the coordinate input surface. And a display device 104 for displaying a drawing result, a keyboard 105, and a mouse 106. In the following, the tablet plate 102 and the tablet pen 103 will be appropriately referred to as a tablet 150. Note that the configuration may be such that the keyboard 105 and the mouse 106 are omitted depending on the mode of use.
[0042]
Main device 101 inputs information on coordinates output from tablet 150 and executes the corresponding functions. Specifically, it performs functions based on ordinary mouse actions such as click, double-click, right-click, drag, and scroll based on information about coordinates. , Brush writing in the solid brush mode, thirst brush mode, thin ink brush mode, etc., and erasing of the drawn image (eraser mode). The drawing mode or software processing will be described later. As the main device 101, various computers including a personal computer can be used. Therefore, it can be said that the main device 101 is a computer device having an enhanced function as a brush drawing device. By using a personal computer or the like, it is possible to easily design the brush writing apparatus 100.
[0043]
The tablet board 102 detects input of coordinates by the tablet pen 103, transmits its position information (absolute position information or relative position information) to the main device 101 side, and serves as an auxiliary input device for realizing various functions. Play a role. In addition, the tablet pen 103 plays a role as an auxiliary input device when inputting coordinates to the tablet board 102 by touching or approaching a predetermined coordinate input area (coordinate input surface) on the tablet board 102.
[0044]
FIG. 2 is an explanatory diagram showing a configuration example of a tablet (tablet plate and tablet pen). The tablet board 102 has a one-to-one correspondence with the screen of the display device 104 and receives a coordinate input from the tablet pen 103, a pen stand 122 on which the tablet pen 103 stands, a detection signal indicating presence / absence of coordinate input, And a transmission line 123 for transmitting coordinate values and the like to the main unit 101. In addition to the above-described detection signals and coordinate values, the tablet board 102 generates pressure information, normal mouse signals such as right click, left click, double click, and drag by the tablet pen 103 and signals related to an eraser function described later. And a signal generator (not shown) for performing the operation. Here, the mode in which the generation of the coordinate values and the pressure values and the determination of the coordinate input detection are performed on the tablet board 102 side has been described, but the main body apparatus 101 side may perform the determination depending on the usage mode.
[0045]
The tablet pen 103 is used to provide a pen tip portion 131 having a pen pressure sensor to reproduce the texture of an actual writing brush when inputting coordinates to the coordinate input surface 121 and an eraser function (eraser mode) described later. It has an eraser 132 to be used, a side switch 133 for generating a right click signal of the mouse, and a side switch 134 for generating a double click signal. Needless to say, the side switches can be assigned in various ways, and the side switch 133 may be set to left click and the side switch 134 may be set to right click. In the present embodiment, the tablet 150 is designed to perform reading by an electromagnetic induction method (electromagnetic transfer function method), with a pen pressure of 512 steps, a reading speed of 200 times per second, and a readable height of 5 mm. are doing. Therefore, it can be said that the coordinate input surface 121 is formed from a position 5 mm above the physical physical surface.
[0046]
Although the side switch 133 and the side switch 134 are integrally formed as a seesaw switch as shown in the figure, the invention is not limited to this, and they may be separate switches or buttons. A signal from the tablet pen 103 is detected on the tablet board 102 side, and transmitted from the signal generation unit to the main device 101. Although the pen pressure sensor is provided on the tablet pen 103 side here, the pen pressure may be detected on the coordinate input surface 121 side.
[0047]
Note that, as functions of the tablet pen 103, in addition to the pen pressure function described above and an eraser function described later, a tilt detection function for detecting the tilt of the tablet pen 103 with respect to the coordinate input surface 121, and a plurality of tablet pens 103 inputting a single coordinate A device ID function for individually recognizing each tablet pen when operating on the surface 121 and a rotation detection function for detecting rotation with respect to the pen axis may be provided. The device ID function is assigned to each tool of the application software, and is used when a plurality of brushes (for example, a bold brush, a medium brush, a teacher's red brush) are used separately without setting a menu each time. You may.
[0048]
The display device 104 displays various processing results (drawing results) executed by the main device 101. As the display device 104, a liquid crystal monitor or a CRT monitor can be used. In the case of performing in a large conference hall, a projector may be used.
[0049]
The keyboard 105 is used when performing text input and command designation as needed. The mouse 106 is used when various instructions are given by a normal computer operation other than drawing.
[0050]
In the present embodiment, a mode in which coordinate input is performed using the tablet plate 102 and the tablet pen 103 will be described. However, various coordinate input devices (coordinate input systems) can be employed as the tablet. That is, in the present invention, the method of detecting the input of coordinates is not particularly limited, and an electric or magnetic method of detecting an input by an electric or magnetic change, an optical method of detecting the intensity or weakness of light. Expressions and the like can be adopted.
[0051]
Further, the coordinate input surface 121 and the display device 104 may be integrally configured, and may be configured as a so-called touch panel or a liquid crystal pen tablet. FIG. 3 is a diagram illustrating an external configuration of a liquid crystal pen tablet in which a coordinate input surface and a display device are integrally configured. As illustrated, since the coordinate input surface 121 and the display device 104 are integrated, the operator can use the tablet pen 103 to perform an extremely intuitive brushstroke drawing as if the display surface were a semi-paper. It becomes possible.
[0052]
(Brush writing device: hardware configuration)
Next, a hardware configuration of the brush writing apparatus 100 will be described. FIG. 4 is an explanatory diagram showing an example of the hardware configuration of the brush drawing apparatus of the present invention. The writing brush drawing apparatus 100 has a CPU 401, a ROM 402, a RAM 403, a hard disk (HD) 404, a graphics card 405, a tablet board 102, a tablet pen 103, a display device 104, a keyboard ( K / B) 105 and a mouse (MOUSE) 106.
[0053]
The CPU 401 controls the entire brush drawing apparatus 100 together with the OS, and controls processing of various software. Specifically, for example, the CPU 401 executes various functions set at the coordinates based on the coordinate information and the pressure information from the tablet 150 according to a program stored in the hard disk 404 or the ROM 402. The CPU 401 also performs drawing control for the VRAM (image RAM) of the graphics card 405, control for temporarily storing work data stored in the hard disk 404 in the RAM 403, and the like.
[0054]
The ROM 402 stores a boot program and the like. Depending on the mode of use, the ROM 402 may store a control program for the tablet 150. The RAM 403 is used as a work area of the CPU 401. Specifically, various programs read from the hard disk 404 are temporarily stored. In addition, the RAM 403 temporarily stores coordinate information and pressure information received from the tablet board 102 and the mouse 106. This information is used as auxiliary information when executing a function corresponding to the corresponding application or icon. In particular, the present invention is also used as information for controlling a drawing pattern.
[0055]
The hard disk 404 stores various software programs (software) such as an operating system (OS), application programs, and drivers.
[0056]
The graphics card 405 sends an image signal to be output to the display device 104. The graphics card 405 also includes a VRAM that stores an image signal to be output and an image output interface (image output I / F) that outputs the processed image signal to the display device 104. In operation, the image output I / F outputs RGB image data developed in the VRAM to the display device 104.
[0057]
Although not shown, the brush writing apparatus 100 also includes an input interface (input I / F) for performing input control of coordinate information input to the coordinate input surface 121. As the input I / F, for example, a connection mode using RS232C, USB, or the like can be adopted. Various processes including a drawing process are executed via the CPU 401 and the OS of the hard disk 404 and corresponding applications based on the coordinate information input from the coordinate input I / F.
[0058]
In addition, the brush drawing device 100 can be equipped with a flexible disk drive device, a CD-ROM drive device, an MO drive device, and the like.
[0059]
The hard disk 404 stores an OS 441, brush writing software 442 for realizing brush writing, and driver software 443 for controlling the tablet 150 so that the tablet 150 can be used with the brush writing device 100. In addition, the hard disk 404 stores various software such as word processing software and spreadsheet software.
[0060]
The driver software 443 emulates a signal generated by the tablet 150 into a mouse event, controls the OS 441 so that it can be interpreted, and maps each point on the coordinate input surface 121 one-to-one with a coordinate space managed by the OS. Perform the corresponding control. In calculating the coordinate position, the tablet 150 may grasp the coordinate value and send it to the main body device 101 side, or a predetermined signal from the tablet 150 side may be received by the main body device 101 side and the main body device 101 may receive the signal. A configuration in which the coordinate values are grasped on the device 101 side may be used. Similarly, the pressure (writing pressure) when the tablet pen 103 is inputting coordinates to the tablet board 102 may be a mode in which the pressure value is grasped on the tablet 150 side and transmitted to the main device 101 side. Alternatively, a configuration may be adopted in which a predetermined signal from the tablet 150 is received by the main device 101 and the main device 101 grasps the pressure as a pressure value.
[0061]
(Functional Configuration of Brush Drawing Apparatus 100: Functional Configuration Related to Trajectory of Drawing Pattern)
Next, among the functional configurations of the brush drawing apparatus 100, a functional configuration related to drawing control of a locus of a drawing pattern will be described. The brush drawing device 100 performs drawing in various brush drawing modes according to the brush drawing software 442 linked with the tablet 150. The brush drawing mode is roughly divided into a drawing execution mode for reproducing a high-quality brush drawing in consideration of the type of the brush and the amount of ink, and an erasing mode (eraser mode) for erasing a locus drawn in the drawing execution mode. , Can be divided into
[0062]
The drawing execution mode is a normal brush mode that reproduces the normal brush drawing texture, a solid brush mode that reproduces the brush drawing texture that has enough ink and almost no smearing, a dry mode that reproduces the blurred expression, and a sufficient brush ink Is generated by the thin brush mode. The brush-drawing apparatus 100 mainly reproduces brush-drawing using ink, with good texture, but also has a brush watercolor mode and a brush oil painting mode in consideration of advantages realized by a computer system. In addition, the background is assumed to have no particular irregularities such as half-paper, but in addition, background processing for realizing a brushstroke on the irregularized background is also executed. These will be described later.
[0063]
FIG. 5 is an explanatory diagram showing an example of a functional configuration that governs a trajectory of brush drawing in the brush drawing apparatus of the present embodiment. The brush drawing device 100 includes a coordinate input unit 501, a coordinate value detection unit 502, a pressure detection unit 503, a drawing pattern scaling unit 504, a movement direction calculation unit 505, and the like as functional components that determine the trajectory of the brush drawing. , A drawing pattern rotation unit 506, a distance interval calculation unit 507, a rotation control unit 508, a rotation determination unit 509, a drawing pattern shortening unit 510, and a drawing unit 511.
[0064]
The coordinate input unit 501 inputs coordinate information. The coordinate information is information input to the tablet board 102 and includes the coordinate value itself or information necessary for calculating the coordinate value. It may also include a different input mode, such as a continuous input time. The function of the coordinate input unit 501 can be realized by, for example, the tablet 150, the driver software 443, and the like.
[0065]
The coordinate value detection unit 502 detects the coordinate value of the coordinates input by the coordinate input unit 501 at predetermined time intervals. The coordinate values may be absolute coordinates or relative coordinates. The coordinate system may be based on the resolution (800 × 600 pixels, 1024 × 768 pixels, etc.) set by the OS 441, or may be based on measured values (the coordinate input surface 121 is configured as a 127 mm × 99 mm surface, and the reading resolution is Mm measurement value ± 0.25 mm). The function of the coordinate value detection unit 502 can be realized by, for example, the tablet 150, the RAM 402, the OS 441, the driver software 443, and the like.
[0066]
The pressure detection unit 503 detects a pressure value when the tablet pen 103 is inputting coordinates on the coordinate input surface 121. In the following, this pressure will be referred to as writing pressure as appropriate. The drawing pattern enlargement / reduction unit 504 enlarges or reduces the size of a drawing pattern to be drawn by the drawing unit 511 according to the pressure detected by the pressure detection unit 503. Specifically, when the pressure is high or high, the drawing pattern is increased, and when the pressure is low or low, the drawing pattern is reduced. Here, the enlargement or reduction does not only mean a similar shape but also includes a change in the width of the base portion and the tip portion of the brush of the drawing pattern and the change in the length from the tip portion to the tip portion. Next, specific enlargement / reduction processing will be described.
[0067]
FIG. 6 is an explanatory diagram showing the relationship between the drawing pattern and the pen pressure. 6 (a) and 6 (c) show a drawing pattern of a round brush generally used in calligraphy, and FIG. 6 (b) shows a drawing pattern of a flat brush. FIG. As shown in the drawing, in the case of a round brush, the base portion is based on a circle, and the brush tip portion is based on a trapezoid, and the drawing pattern is represented by two figures. On the other hand, in the case of a flat brush, a drawing pattern is represented by a figure having only a trapezoid.
[0068]
As the shape change (enlargement / reduction processing) of the drawing pattern due to the pen pressure, there is a method of performing a control of maximizing the width of the root at the time of the maximum writing pressure value and making the width of the writing tip wider than the width of the root. At this time, it is preferable to perform control such that the smaller the writing pressure value, the shorter the writing brush length and the narrower the writing brush width. More specifically, in the case of a round brush, in the state where the writing pressure is at a minimum, the width of the tip is made smaller than the width of the root, and control is performed so that the shape approaches a shape obtained by combining two figures, a root is a circle and a tip is a triangle. Do it. In the case of a flat brush, control is performed such that the length of the brush approaches a rectangular shape shorter than the width of the brush when the writing pressure is at a minimum.
[0069]
As an example of realizing the above-described shape change shown in FIG. 6, the following shape determination formula can be adopted. FIG. 7 is an explanatory diagram that defines each variable for creating a drawing pattern.

In addition, the initial size of the brush (large brush, medium brush) can be freely set using the brush length (L1), base width (W2), and tip width (W1) at the maximum writing pressure used in this formula as variable parameters. , Small brush).
[0070]
In the above equation, the drawing model is such that the pen tip spreads as the pen pressure increases, but a drawing model whose pen tip shape does not depend on the pen pressure may be adopted (see FIG. 6C). In this case, it is preferable to use a drawing pattern with a closed brush tip so that the beginning of writing and the drawing of a thin character are not unnatural and fat.
[0071]
The function of the pressure detection unit 503 can be realized by the tablet 150 and the driver software 443, for example. The function of the drawing pattern scaling unit 504 can be realized by, for example, the CPU 401, the RAM 403, the writing brush software 442, and the like.
[0072]
The movement direction calculation unit 505 calculates the movement direction of the tablet pen 103 based on the coordinate values sequentially detected by the coordinate value detection unit 502. The drawing pattern rotation unit 506 rotates the drawing pattern so that the brush tip of the drawing pattern faces in the direction opposite to the movement direction calculated by the movement direction calculation unit 505. The brush drawing apparatus 100 draws a drawing pattern in correspondence with sampling points (coordinate values sequentially detected) of the tablet board 102 and performs brush drawing by interpolating between the sampling points. Step 506 changes the direction of the brush tip at each sampling point according to the direction of travel of the brush.
[0073]
As the processing at this time, first, it is necessary to determine the initial angle of the brush tip when the tablet pen 103 is lowered. In the brush drawing device 100, the sampling point from the position at which the tablet pen 103 starts inputting coordinates (the position in contact with the tablet plate 102) until the tablet pen 103 moves a certain distance or more is skipped. The traveling direction of the tablet pen 103 is obtained from the coordinate value and the coordinate value at the time of starting the input, and the direction (initial angle) of the drawing pattern is calculated according to this direction.
[0074]
This is because camera shake is likely to occur before and after the writing of the brush. For example, the sampling point immediately before the tablet pen 103 is lowered and the sampling point when the tablet pen 103 touches the tablet plate 102 (coordinate input is started) are determined. This is because, when the traveling direction of the brush is obtained and the initial angle is calculated, the movement amount of the brush is small and the calculation error becomes very large. Note that the threshold value of the moving distance of the tablet pen 103 for determining the initial angle can be set to ４ of the maximum length L1 of the drawing pattern (see FIG. 7).
[0075]
After determining the initial angle, the moving direction calculation unit 505 and the drawing pattern rotation unit 506 sequentially determine the direction of a straight line connecting each sampling point and rotate the tip of the drawing pattern. The position of the tablet pen 103 immediately before (x_i-1, Y_i-1) And the current position to (x_i, Y_i), The orientation θ of the drawing pattern is
θ = Tan^-1(-(Y_i-Y_i-1) / (X_i-X_i-1)) ・ ・ ・ Equation (1)
Becomes FIG. 8 shows the relationship between the direction θ of the drawing pattern and the moving direction of the tablet pen.
[0076]
The function of the moving direction calculation unit 505 can be realized by, for example, the driver software 443, the RAM 403, the CPU 401, and the brush drawing software 442. The function of the drawing pattern rotation unit 506 can be realized by, for example, the RAM 403, the CPU 401, the brush drawing software 442, and the like.
[0077]
The distance interval calculation unit 507 calculates an adjacent distance interval of the coordinate values sequentially detected by the coordinate value detection unit 502. Further, the rotation control unit 508 controls the drawing pattern rotation unit 506 based on the distance interval of the coordinate values calculated by the distance interval calculation unit 507, and reduces the rotation amount of the drawing pattern. That is, the rotation control unit 508 realizes drawing in consideration of “inertia” in the corner portion. In other words, unnatural projection drawing at the corner portion is prevented.
[0078]
Observing the actual brushstroke drawing in detail, in fact, in the corner portion, the direction of the brush does not change rapidly due to factors such as friction, but changes slowly with a slight delay. The brush writing apparatus 100 is provided with a parameter called "inertia" to express such characteristics, and can freely adjust the degree of change in the direction of the brush (rotation of the drawing pattern). Except for the initial angle when the tablet pen 103 is lowered, the amount of change in the direction of the brush is adjusted by this inertia parameter.
[0079]
When performing drawing using inertia in the brush writing apparatus 100, the rotation control unit 508 determines the rotation angle θ ‘._iIs calculated by the following equation.
θ ‘_i= Θ ‘_i-1+ (100-m) · Δθ_i/ 100 ・ ・ ・ Formula (2)
Δθ_i= Θ_i−θ ‘_i-1(-Π <Δθ_i≦ π)
here,
θ ‘_i-1回 転 Rotation angle at sampling point i-1 (with inertia)
θ_i方向 A direction opposite to the moving direction of the tablet pen 103 at the sampling point i obtained by the moving direction calculation unit 505 (no inertia)
Δθ_i回 転 Change amount of rotation angle at sampling point i-1 (-π to π)
m inertia (0-100)
Note that θ ‘_i-1Uses the initial angle described above immediately after landing (immediately after the start of coordinate input), and otherwise uses the rotation angle calculated by equation (2) at the immediately preceding sampling point. Δθ_iUses an angle normalized to the range -π to π.
[0080]
As is clear from the equation (2), the larger the value of the inertia m, the slower the rotation. When m = 100, there is no rotation (θ ‘_i= Θ ‘_i-1), M = 100, the opposite direction θ ‘of the traveling direction of the tablet pen 103_i= Θ_iBecomes
[0081]
The above is the processing of determining the direction of the drawing pattern using the inertia m. In the brush writing apparatus 100, the inertia m is changed according to the moving speed of the tablet pen 103. This can prevent unnatural projections occurring at the folded portions of the characters when the drawing pattern is simply superimposed on the position detected by the coordinate value detection unit 502 and drawn. FIG. 9 is a drawing conceptual diagram showing an unnatural protrusion drawing in a corner and the direction of a drawing pattern when inertia is controlled. 9 (a) is a drawing without considering inertia, and FIG. 9 (b) is a drawing showing the orientation of the drawing pattern before and after the corner portion in the drawing shown in FIG. 9 (a). FIG. 9C is a diagram showing the orientation of the drawing pattern in consideration of inertia.
[0082]
The unnatural projection is caused particularly by the fact that when the pen is moved slowly, the drawing pattern is rotated before the pen is completely lowered. The rotation control unit 508 controls the rotation so that the inertia m increases when the moving speed of the tablet pen 103 is low. For the rotation control, for example, the following equation can be adopted.
m '_i= MAX (100−rf_i, M)
rf_i= (D_i ²・ Α) / (MAX (l1_i, L1_i-1) + 1) + β
(However, D_iRf if = 0_i= 0)
D_i ²= (X_i-X_i-1)²+ (Y_i-Y_i-1)²
here,
m '_i補正 Corrected inertia value at sampling point i (0 to 100)
m inertia value before correction (0 to 100) (used as lower limit)
rf_i回 転 Rotation coefficient at sampling point i
D_i距離 Distance between sampling point i and sampling point i-1
l1_i描画 Length of drawing pattern at sampling point i
l1_i-1描画 Length of drawing pattern at sampling point i-1
α, β Constants for fine adjustment (eg α = 10, β = 3)
x_i, Y_i座標 Coordinate value of sampling point i
x_i-1, Y_i-1座標 Coordinate value of sampling point i-1
The coordinates are managed by integer values.
Therefore, the final rotation angle θ ‘_iBecomes the following equation.
θ ‘_i= Θ ‘_i-1+ {(100-m '}_i) ・ Δθ_i/ 100 ・ ・ ・ Equation (3)
[0083]
As described above, by performing drawing while changing the inertia value m according to the moving speed of the tablet pen 103, unnatural projection drawing at the corner portion is suppressed. In addition, when the pen is moved slowly, not only in the corners, when the pen is moved slowly, unnatural swelling may occur in the middle of the line due to camera shake or an increase in calculation error, but this phenomenon is also eliminated. The function of the distance interval calculation unit 507 can be realized by, for example, the brush drawing software 442, the RAM 403, the CPU 401, and the like. The function of the rotation control unit 508 can be realized by, for example, the brush drawing software 442, the RAM 403, the CPU 401, and the like.
[0084]
The turning determining unit 509 determines whether or not the moving direction calculated by the moving direction calculating unit 505 has suddenly turned. In addition, when the turning determination unit 509 determines that the moving direction has suddenly turned, the drawing pattern shortening unit 510 shortens the length of the drawing pattern by a predetermined number of drawings or a predetermined drawing distance. When a large direction change close to 180 degrees such as turning is performed, an unnatural projection may be drawn even when the inertia is considered (see FIG. 10). Prevent drawing.
[0085]
When observing the actual brushstroke drawing in detail, in fact, at the turn-back portion, a beautiful drawing is realized by turning over the brush tip. The brush drawing apparatus 100 addresses this problem by simulating the turning over of the brush tip. Specifically, first, the tip rotation rate rr at each sampling point is determined in order to determine the turning over of the tip._iCalculate
rr_i= | Δθ_i| · 100} / {π} ... Equation (4)
Δθ_i= Θ_i−θ ‘_i-1(-Π <Δθ_i≦ π)
here,
rr_i筆 Tip rotation rate at sampling point i
θ ‘_i-1回 転 Rotation angle (with inertia) at sampling point i-1 obtained by equation (3)
θ_i回 転 Rotation angle at sampling point i obtained by equation (1) (no inertia)
Δθ_i回 転 Change amount of rotation angle at sampling point i-1 (-π to π)
[0086]
The rotation determining unit 509 calculates the tip rotation rate rr calculated by the equation (4)._iIs greater than or equal to a certain value, it is determined that the writing tip has been turned over, that is, the moving direction has suddenly turned. This constant value can be, for example, 80. If it is determined that the tip is turned over, the brush drawing apparatus 100 sets the tip reversal flag, stores the coordinate value (tx, ty) at the sampling point, and sets the rotation angle to θ ‘._i-1= Θ_i, Θ ‘_i= Θ_iDraw as
[0087]
When the tip reversal flag is set, the drawing pattern shortening unit 510 adopts a drawing pattern in which the length of the tip is temporarily shortened. Brush length l1_i‘Can be calculated by the following equation, for example.
l1_i’= Dt_i・ (L1_i-W2_i) / L1 + w2_i(For round brush)
l1_i’= Dt_i・ L1_i/ {L1} (for flat brush)
Dt_i= Sqrt ((x_i-T_x)²+ (Y_i-T_y)²)
Where Dt_iDt if> L1_i= L1
here,
Dt_i距離 Distance from sampling point i to turning point
x_i, Y_i座標 Coordinate value of sampling point i
tx, ty Coordinate value of turning point
w2_i幅 Width of the root of drawing pattern at sampling point i
l1_i描画 Length of drawing pattern at sampling point i
L1 Maximum length of drawing pattern
The distance Dt from the turning point of the sampling point i_iMay be approximated by the following equation.
Dt_i= | X_i−tx | + | y_i−ty | where Dt_iDt if> L1_i= L1
[0088]
The turning judgment unit 509 calculates Dt_iAt the time when ≧ L1, a process of clearing the tip reversal flag is performed. In this way, when it is determined that the brush tip is turned over, the length of the brush tip is temporarily corrected to be short, and drawing is performed with a drawing pattern close to a circle, thereby simulating the tip of the brush and turning it over. In this case, it is possible to eliminate the drawback of drawing at the turning point.
[0089]
The function of the turning determination unit 509 can be realized by, for example, the brush drawing software 442, the RAM 403, the CPU 401, and the like. If the tablet pen 103 has a tilt detection function of detecting a tilt with respect to the coordinate input surface 121, the tablet pen 103 is also a functional component of the rotation determination unit 509. The function of the drawing pattern shortening unit 510 can be realized by, for example, the brush drawing software 442, the RAM 403, the CPU 401, and the like.
[0090]
The drawing unit 511 detects a drawing pattern rotated by the drawing pattern rotation unit 506 or the rotation control unit 508, enlarged or reduced by the drawing pattern scaling unit 504, and shortened in length by the drawing pattern shortening unit 510, for coordinate value detection. Drawing is sequentially performed at the coordinate positions detected by the unit 502. At the time of drawing, a process of filling a gap between the sampling points is performed by drawing a drawing pattern for interpolation between each sampling point. At this time, if you simply draw using a similar drawing pattern, draw the interpolation pattern so that the hot spot of the drawing pattern overlaps the position of a point that forms a straight line connecting each sampling point. Just fine. However, the drawing model adopted by the brush drawing device 100 changes the shape of the drawing pattern depending on the pen pressure and the direction of movement of the brush, so that the brush tip may draw a locus longer than a straight line connecting the sampling points, In the interpolation processing, there are gaps in some places, and smooth interpolation cannot be performed.
[0091]
Therefore, the drawing unit obtains the number of interpolation points based on the length of the longest straight line connecting the vertices of the polygon forming the drawing pattern at each sampling point, and determines the pen pressure and the traveling direction at each interpolation point. Also, processing for drawing a drawing pattern formed by gradually changing is performed.
[0092]
In the case of a round brush, the straight line distance between the middle points on the circumference indicating the base of the brush and the vertices of the trapezoid indicating the brush tip is calculated.In the case of the flat brush, each vertex of the trapezoid indicating the brush tip is calculated. Find the linear distance between them. The number of interpolation points is determined from the length of the longest straight line between these vertices. Specifically, assuming that the starting coordinate of the reference line is (x1, y1) and the ending coordinate is (x2, y2), if | x2-x1 | ≧ | y2-y1 |, the number of interpolation points is | x2-x1 | When | x2-x1 | <| y2-y1 |, the number of interpolation points is | y2-y1 |. Note that the coordinate values are integer values.
[0093]
The drawing unit 511 calculates the coordinates of each interpolation point based on the number of interpolation points obtained in this way, and draws the hot spot of the drawing pattern at each interpolation point so as to follow a straight line connecting each sampling point. . Note that the locus of a line connecting the vertices of the drawing pattern draws a curve in actual drawing, so that the number of interpolation points obtained by multiplying the number of interpolation points by 1.2 to 1.5 may be used. The amount of change in the variables such as the pen pressure and the rotation angle during the interpolation is obtained by dividing the difference of each variable between two points to be interpolated by the number of interpolations.
[0094]
The brush-drawing apparatus 100 enables brush-drawing with a high texture by the drawing processing of the drawing unit 511. The function of the drawing unit 511 can be realized by, for example, the brush drawing software 442, the RAM 403, the CPU 401, the graphics card 405, the display device 104, and the like.
[0095]
(Functional Configuration of Brush Drawing Apparatus 100: Functional Configuration Related to Expression of Drawing Pattern itself)
Next, among the functional configurations of the brush writing apparatus 100, a functional configuration related to the expression of the rendering pattern itself will be described. In actual brush drawing, a plurality of factors, such as a bunch of hairs constituting the brush, the amount of ink, ease of ink smearing, and ease of separation, are intertwined to form a unique drawing texture (blurring, smearing). In the brush drawing apparatus 100, the drawing texture is expressed by changing the internal image of the drawing pattern.
[0096]
FIG. 11 is an explanatory diagram showing an example of a functional configuration for changing an internal image of a drawing pattern in the brush writing apparatus of the present embodiment. The brush writing apparatus 100 includes a grayscale image adjustment unit 512, a stop determination unit 513, a smoothing unit 514, a stop number counting unit 515, and a smoothing control unit 516 as functional components for changing the expression in the drawing pattern. And Here, first, a general gray-scale image inside a drawing pattern will be described, and then each functional configuration will be described.
[0097]
FIG. 12 is a diagram showing an example of a drawing pattern used in the brush drawing apparatus 100 and a grayscale image inside the drawing pattern. By using a drawing pattern with shading and gaps, a high-quality drawing reflecting the locus of each brush can be achieved. As a method of generating a drawing pattern, for example, a method of randomly arranging a point pattern that gradually becomes thinner as it moves away from the center into the drawing pattern can be cited. Specifically, the following point patterns can be used.
P_xy= A ・ D_xy ²(0 ≦ P_xy≤ 255)
(However, P_xyP for> 255_xy= 255)
here,
P_xy輝 度 Pixel brightness (color value)
D_xy距離 Distance between the center point and its pixel
a coefficient for adjusting the spread
In the drawing pattern, the amount of the gap can be adjusted by adjusting the value of the coefficient a of the point pattern.
[0098]
Other methods of generating the drawing pattern include, for example, generating an appropriate number of random points using random numbers, blurring the points with a smoothing filter according to the drawing mode, and adjusting the brightness level so that the drawing pattern does not become thin. May be obtained by performing the correction of.
[0099]
Note that the smoothing filter is a processing filter that focuses on a certain central pixel (pixel of interest) and neighboring pixels, and averages colors in a specified adjacent range. When a rectangular filter is used, a square blur is applied. Therefore, a different weight may be applied depending on the distance from the pixel of interest to perform a round blur.
[0100]
Hereinafter, a unit image that has been subjected to a point pattern or a smoothing filter and is blurred or blurred is referred to as a grayscale image. By adjusting the grayscale image, it is possible to reproduce the faintness and bleeding peculiar to the brush with good texture.
[0101]
First, a description will be given of a functional unit capable of expressing blur. The grayscale image adjustment unit 512 adjusts the number, size, and grayscale of the grayscale images according to the pressure detected by the pressure detection unit 503 and the distance interval between the coordinate values determined by the distance interval calculation unit 507. In addition, depending on the mode of use, the mode may depend only on the pressure, or the mode may depend only on the distance interval. Further, only the number may be adjusted, only the size may be adjusted, or only the shading may be adjusted. Further, a mode in which two of the number, size, and shading are adjusted may be employed.
[0102]
In the brush drawing apparatus 100, in order to reduce the calculation processing load, for example, the size of a point is limited to three levels of large, medium, and small, and the parameter adjustment at the time of the luminance level correction is used in combination, so that the gap is apparently continuous. The amount can be adjusted. The adjustment of the grayscale image is determined at the initial stage when the drawing mode is selected, and is dynamically changed during the drawing. The adjustment by the grayscale image adjustment unit 512 allows the gap amount to be automatically increased or decreased according to the pen pressure or the speed of the tablet pen 103. As a result, a faint expression with a high texture can be realized. The function of the grayscale image adjustment unit 512 can be realized by, for example, the brush drawing software 442, the RAM 403, the CPU 401, and the like.
[0103]
Next, a description will be given of a functional unit that expresses bleeding. The stop determination unit 513 determines whether or not the tablet pen 103 is stopped based on the coordinate values detected by the coordinate value detection unit 502. The smoothing unit 514 performs a smoothing process on the drawing pattern when the stop determination unit 513 determines that the tablet pen 103 is stopped. The number-of-stops counting section 515 counts the number of times that the stop determination section 513 determines that the tablet pen 103 is stopped at the same place. The smoothing control unit 516 controls the smoothing unit 514 to increase the diffusion parameter of the smoothing process according to the number counted by the number-of-stops counting unit 515.
[0104]
In actual brushstroke drawing, when ink is drawn so that ink and water are easily separated from each other (for example, light black ink) into the brush, bleeding is particularly observed at a stop point. In the writing brush drawing device 100, when the tablet pen 103 stops, the smoothing filter with a large diffusion coefficient is applied to the drawing pattern in accordance with the stop time and drawing is performed, so that the blur can be expressed with a high quality. Smoothing processing is adopted for the reproduction of bleeding. At this time, by not performing luminance correction, it is possible to easily represent a state in which the density gradually decreases. FIG. 13 is a diagram showing a state in which a smoothing process is sequentially performed on a drawing pattern and a blur is propagated. Note that, instead of gradually increasing the diffusion coefficient, the drawing pattern used last time is stored, and by using a drawing pattern that has been subjected to a smoothing process on top of it, the propagation of the blur can be expressed.
[0105]
The functions of the smoothing unit 514 and the smoothing control unit 516 can be implemented by, for example, the brush drawing software 442, the RAM 403, the CPU 401, and the like. The function of the number-of-stops counting section 515 can be realized by, for example, the tablet board 102, the driver software 443, the brush drawing software 442, and the like.
[0106]
The drawing unit 511 sequentially draws the drawing pattern determined or adjusted through the processing of each of these functional units for changing the grayscale image in the drawing pattern at the coordinate position input by the tablet pen 103. In addition, the brush drawing device 100 reproduces a brush writing image using ink with high texture on the display device 104. In addition, it is possible to reproduce drawing by a watercolor brush or an oil brush using a similar algorithm. In particular, when an oil-painting brush is reproduced, an emboss filter may be applied to the drawing pattern to add a shadow. FIG. 14 is a diagram showing a shadow pattern and a drawing example. Among these, FIG. 14A shows a drawing pattern before processing, FIG. 14B shows a drawing pattern after applying an emboss filter, and FIG. 14C shows a drawing example. .
[0107]
(Drawing sample of the brush drawing device 100)
Next, a drawing example of the brush drawing device 100 will be described. FIG. 15 is a diagram illustrating a drawing example of the brush drawing device. As shown in the drawing, it can be understood that drawing expressions equivalent to actual brush drawing, such as "stop", "splash", "hari", and "kaeshi", are possible. In particular, it can be confirmed that the texture at the place where the tablet pen 103 starts inputting the coordinates and the place where the input of the coordinates has been completed are reproduced extremely well.
[0108]
FIG. 16 is a diagram illustrating examples of writing brushes in various drawing modes. FIG. 17 is a table showing parameters of various drawing modes shown in FIG. As shown in the figure, the round brush expresses each of the drawing modes of a normal brush, a solid brush, a dry brush, and a light brush, and the flat brush expresses the drawing modes of a watercolor brush and an oil brush. It can be seen that various drawing expressions are possible by appropriately setting the parameters.
[0109]
The brush drawing device 100 also has an eraser mode. The eraser mode refers to a mode in which, when the eraser 132 of the tablet pen 103 is inputting coordinates on the coordinate input surface 121, a line image of a traced portion is erased along the locus. The eraser mode can achieve a different drawing texture than the undo function of the computer system. Since the eraser mode is linked with the tablet pen 103, it eliminates the complexity of the eraser mode selection that has been realized by a plurality of icon clicks and pull-down selections as in the related art. Operability can be improved.
[0110]
(Processing flow of brush writing device)
Next, a processing flow of the brush drawing apparatus 100 will be described. FIG. 18 is a flowchart illustrating an example of a processing flow of the brushstroke drawing device 100. The brush drawing apparatus 100 first determines a drawing mode (step S601). More specifically, a drawing pattern and a control parameter during drawing of the drawing pattern are determined (see FIG. 17).
[0111]
Subsequently, the coordinate value of the coordinates input by the tablet pen 103 is detected at predetermined time intervals, and the pressure at the time of inputting the coordinates is detected (step S602). Since the tablet 150 is used in the brush drawing apparatus 100, the tablet 150 can detect information on coordinates and pressure. Next, the moving direction of the tablet pen 103 is calculated from the locus of the coordinate values, and the orientation of the drawing pattern (the direction of the pen) is determined (step S603). At the time of the determination, the tablet pen 103 is oriented with a predetermined inertia toward a direction exactly opposite to the moving direction. Specifically, a process of reducing the rotation amount of the rotation angle as the moving speed of the tablet pen 103 becomes smaller is performed.
[0112]
Subsequently, it is determined whether or not the direction of the input coordinates has rapidly turned (step S604). If it is determined that the direction has suddenly turned, processing for reducing the length of the drawing pattern is performed (step S605). Through steps S603, S604, and S605, unnatural projections do not appear on the corners and folded portions of the character being drawn, and a natural brushstroke drawing texture can be obtained.
[0113]
Finally, a drawing pattern is sequentially drawn at each sampling point (step S606). The drawing pattern to be drawn on the sampling point is appropriately changed according to various conditions, based on the image of the initial setting of the drawing mode determined in step S601. Specifically, the number, the size, and the shading of the shading images forming the drawing pattern are adjusted according to the pen pressure and speed of the tablet pen 103. In particular, in the case of the light ink brush mode, smoothing processing is sequentially performed according to the dwell time of the tablet pen 103 to draw a drawing pattern in which ink droplets are blurred.
[0114]
Each of the above functional units can be realized as a computer program. That is, the computer system can be made to function as means for realizing each functional unit. 19 to 24 are diagrams illustrating screen configuration examples when the processing results of the computer program are displayed on the display device 104. FIG. In the screen configuration, a “file” menu 701 is a menu for performing basic operations such as opening, closing, and newly creating a file. The “brush” menu 702 is a menu for performing each of the drawing modes and the eraser mode shown in FIGS. 19 to 24, and custom settings described later.
[0115]
The “background” menu is a menu for setting a base, and for example, a half-sheet (plain), a drawing paper, and a canvas can be set. FIG. 25 is a diagram illustrating an example of a base of an image paper, and FIG. 26 is a diagram illustrating an example of a base of a canvas. As shown in the drawing, in each of the examples of the base, a fixed density image different from that of the plain paper is formed, and the drawing pattern is superimposed, so that a drawing texture in consideration of the base can be obtained. In the actual drawing, the background irregularities may appear on the surface in a watercolor or an oil painting. However, in the brush drawing device 100, for example, an ink painting on a canvas is not used in a real combination. It is also possible to obtain a texture.
[0116]
A “color selection” menu 704 is a menu for selecting various drawing colors. Accordingly, in brushstroke painting, ink ink expression other than black, which has not existed in the past, can be realized. The “delete” menu 705 is a menu for deleting all characters and diagrams drawn on the drawing screen 706.
[0117]
Next, the characteristic (P) of the “brush” menu 702 will be described. Enables custom setting of various parameters for brush drawing. FIG. 27 is a diagram illustrating an example of a setting screen for customizing the size of the drawing pattern. As shown, the length of the drawing pattern, the width of the root, and the width of the tip can be changed. FIG. 28 is a diagram showing an example of a setting screen for customizing a grayscale image and the like. As shown in the figure, the reference value for judging the turning of the tablet pen 103 can be changed by adjusting the combination ratio of the texture pattern and the drawing pattern, the correction amount of the point density, the adjustment of the inertia m. Note that the combination ratio of the texture pattern and the drawing pattern indicates the combination ratio of the unevenness and shading (texture) of the base and the shading of the drawing pattern.
[0118]
FIG. 29 is a diagram illustrating an example of a setting screen for customizing ink (ink). As shown in the figure, it is possible to change the amount of ink, the presence or absence of a change in blur due to pen pressure, the presence or absence of a change in blur due to the speed of the brush, the amount of blur due to speed, and the amount of blur. FIG. 30 is a diagram showing an example of a setting screen for customizing density and contrast. FIG. 31 is a diagram showing an example of a setting screen for customizing the amount of permeation and delay control. Note that the delay control realizes a function of automatically roughening the interpolation and preventing the drawing from following the movement of the pen when the drawing ability of the personal computer is low and drawing cannot catch up. Refers to control.
[0119]
By appropriately programming each of the functional units described above and installing it in a computer system including the tablet 150, the computer can be operated as a brushstroke drawing device. Note that the distribution mode of the program is not limited to a recording medium such as a CD-ROM, and the program can be distributed via an electric line such as the Internet.
[0120]
【The invention's effect】
As described above, the brush drawing device of the present invention (claim 1) includes a tablet having a coordinate input surface and coordinate input means for inputting coordinates with respect to the coordinate input surface, and is a basic drawing shape. A brush writing apparatus for performing drawing in accordance with a locus of a drawing pattern, wherein a coordinate value detecting means detects a coordinate value of coordinates input by the coordinate input means at predetermined time intervals, and a pressure detecting means detects the coordinate input. Means for detecting pressure when coordinates are input to the coordinate input surface, scaling means for expanding or reducing the size of the drawing pattern according to the pressure detected by the pressure detecting means, and moving direction calculating means Calculates the moving direction of the coordinate input means based on the coordinate values sequentially detected by the coordinate value detecting means, and the drawing pattern rotating means determines the opposite of the moving direction calculated by the moving direction calculating means. The drawing pattern is rotated such that the tip of the drawing pattern is oriented in the direction, the distance interval calculating means calculates adjacent distance intervals of the coordinate values sequentially detected by the coordinate value detecting means, and the rotation control means The drawing pattern rotation unit is controlled based on the distance interval of the coordinate values calculated by the interval calculation unit to reduce the amount of rotation of the drawing pattern, and the drawing unit is rotated by the drawing pattern rotation unit or the rotation control unit and is enlarged and reduced. Since the drawing pattern enlarged or reduced by is sequentially drawn at the coordinate position detected by the coordinate value detecting means, the drawing pattern gradually changes direction at the `` quad '' of the character or diagram to be drawn, thereby Using a tablet, natural brush drawing can be reproduced with a good texture.
[0121]
According to a second aspect of the present invention, in the first aspect of the present invention, the turning determination means determines whether or not the moving direction calculated by the moving direction calculating means has rapidly turned. When the pattern determination unit determines that the moving direction is suddenly turned by the rotation determining unit, the pattern reducing unit shortens the length of the drawing pattern by a predetermined number of drawings or a predetermined drawing distance. Since the drawing pattern rotated by the pattern rotation unit and the rotation control unit, enlarged or reduced by the enlargement / reduction unit, and reduced in length by the pattern shortening unit, is sequentially drawn at the coordinate position detected by the coordinate value detection unit, Prevents unnecessary projection drawing by drawing patterns in steep turn-back drawing such as "splashing", thereby regenerating natural brushstrokes with good quality using a tablet. It can become.
[0122]
Further, in the brush-drawing device of the present invention (claim 3), in the brush-drawing device according to claim 1 or 2, the drawing color becomes lighter as the distance increases around a predetermined pixel among the pixels constituting the drawing pattern. A drawing pattern is composed of a plurality of grayscale images, and the grayscale image adjusting means adjusts the grayscale image according to the pressure detected by the pressure detecting means and / or the distance interval of the coordinate value determined by the distance interval calculating means. Since the number and / or the size of the grayscale image and / or the grayscale of the grayscale image are adjusted, and the drawing unit further draws the drawing pattern adjusted by the grayscale image adjustment unit, the blurred expression can be performed. Using a tablet, it is possible to reproduce natural brush strokes with good texture.
[0123]
According to a fourth aspect of the present invention, there is provided the brush-drawing apparatus according to the third aspect, wherein the brush-drawing apparatus obtains a drawing pattern by applying a smoothing filter to a black spot image randomly shaken in the drawing pattern. Since the image is composed of the obtained images, it is possible to use a drawing pattern that can easily compose a blurred expression, and thereby it is possible to reproduce a natural brushstroke with good texture using a tablet.
[0124]
Further, according to a brush writing apparatus of the present invention (claim 5), in the brush writing apparatus according to any one of claims 1 to 4, the stop determination means is based on the coordinate value detected by the coordinate value detection means. To determine whether or not the coordinate input means is stopped, and the smoothing means performs a smoothing process on the drawing pattern when the stop determination means determines that the coordinate input means is stopped. However, since the drawing pattern smoothed by the smoothing means is further drawn, a blurred expression can be realized, whereby a natural brushstroke drawing can be reproduced with a good texture using a tablet.
[0125]
Also, in the brush writing apparatus of the present invention (claim 6), in the brush writing apparatus according to claim 5, the number-of-stops counting means determines that the coordinate input means is stopped at the same place by the stop determination means. The smoothing control means controls the smoothing means to increase the diffusion parameter of the smoothing process in accordance with the number counted by the stop number counting means, and the drawing means further includes a smoothing control means. Renders a smoothed rendering pattern under the control of, so that a dynamic blurring expression is possible, whereby a natural brushstroke rendering can be reproduced with good quality using a tablet.
[0126]
A writing brush drawing program (claim 7) according to the present invention uses an output signal from a tablet having a coordinate input surface and coordinate input means for inputting coordinates on the coordinate input surface to generate a basic drawing shape. A program for drawing a certain drawing pattern in accordance with the locus thereof, comprising: a computer for detecting coordinate values of coordinates input by the coordinate input means at predetermined time intervals; Pressure detecting means for detecting the pressure when the coordinates are input to, a scaling means for enlarging or reducing the size of the drawing pattern according to the pressure detected by the pressure detecting means, and a coordinate value detecting means for sequentially. A moving direction calculating means for calculating a moving direction of the coordinate input means based on the detected coordinate values, and a drawing in a direction opposite to the moving direction calculated by the moving direction calculating means. Drawing pattern rotating means for rotating the drawing pattern so that the brush tip portion of the pattern is oriented; distance interval calculating means for calculating adjacent distance intervals of coordinate values sequentially detected by coordinate value detecting means; and distance interval calculating means. A rotation control unit that controls the drawing pattern rotation unit based on the calculated distance between the coordinate values to reduce the rotation amount of the drawing pattern, and an enlargement or reduction that is rotated by the drawing pattern rotation unit or the rotation control unit and is enlarged or reduced by the scaling unit. The drawn drawing pattern is made to function as a drawing means for sequentially drawing at the coordinate position detected by the coordinate value detecting means, so that the drawing pattern slowly changes direction at a portion of a character or a line to be drawn, Using a tablet, natural brushstroke drawing can be reproduced with good texture.
[0127]
According to a second aspect of the present invention, there is provided the brush-drawing program according to the seventh aspect, further comprising: determining whether or not the moving direction calculated by the moving-direction calculating means has turned rapidly. Turn determination means, and when it is determined that the moving direction is suddenly turned by the turn determination means, to function as a pattern shortening means to shorten the length of the drawing pattern by a predetermined number of drawing or a predetermined drawing distance, As a drawing unit, the drawing pattern rotated by the drawing pattern rotation unit and the rotation control unit, enlarged or reduced by the enlargement / reduction unit, and reduced in length by the pattern shortening unit is placed at the coordinate position detected by the coordinate value detection unit. Since drawing is performed sequentially, unnecessary projection drawing due to a drawing pattern is prevented in steep turn drawing such as “splash”. More, the texture well can reproduce a natural brush drawing by using the tablet.
[0128]
According to a ninth aspect of the present invention, there is provided a brushstroke drawing program according to the seventh or eighth aspect, wherein the drawing color becomes lighter as the distance from a predetermined pixel among the pixels constituting the drawing pattern increases. A plurality of gray-scale images to form a drawing pattern, and further, the computer controls the number of gray-scale images according to the pressure detected by the pressure detecting means and / or the distance interval of the coordinate value determined by the distance interval calculating means. And / or function as a gradation image adjustment unit for adjusting the size of the gradation image and / or the gradation of the gradation image, and further function as a drawing unit to draw the drawing pattern adjusted by the gradation image adjustment unit. Therefore, it is possible to express faintly, and with this, natural brush drawing can be reproduced with good texture using a tablet That.
[0129]
A brushstroke drawing program according to the present invention (claim 10) provides the brushstroke drawing program according to claim 9, wherein the drawing pattern is obtained by applying a smoothing filter to a black dot image randomly shaken in the drawing pattern. Since the image is composed of the obtained images, it is possible to use a drawing pattern that can easily compose a faint expression, and thereby it is possible to reproduce a natural brushstroke with good texture using a tablet.
[0130]
According to another aspect of the present invention, there is provided a brush writing program according to any one of claims 7 to 10, further comprising the step of: causing the computer to execute the program based on the coordinate values detected by the coordinate value detecting means. A stop determining means for determining whether the coordinate input means is stationary, and a smoothing means for performing a smoothing process on the drawing pattern when the stop determining means determines that the coordinate input means is stationary. Function, and as a drawing unit, furthermore, it functions so as to draw a drawing pattern smoothed by the smoothing unit, so that a blurred expression becomes possible, whereby a natural brushstroke drawing can be reproduced with a good texture using a tablet. .
[0131]
Further, the writing brush drawing program (claim 12) is the writing brush drawing program according to claim 11, further comprising: a computer for counting the number of times the coordinate input unit is stopped at the same place by the stop determination unit. Means for controlling the smoothing means in accordance with the number of times counted by the number-of-stops counting means to increase the diffusion parameter of the smoothing process, functioning as a drawing means, further controlling the smoothing control means In response to this, a function of drawing a smoothed drawing pattern is provided, so that dynamic blurring expression is possible, and a natural brush drawing can be reproduced with good quality using a tablet.
[0132]
Also, a brushstroke drawing method according to the present invention (claim 13) includes a tablet having a coordinate input surface and coordinate input means for inputting coordinates with respect to the coordinate input surface, and a locus of a drawing pattern which is a basic shape of drawing. A brush-drawing method applied to a brush-drawing device that performs drawing according to the following. In the coordinate value detecting step, the coordinate value of the coordinates input by the coordinate input means is detected at predetermined time intervals, and in the pressure detecting step, the coordinates are detected. In the input step, the pressure when coordinates are input to the coordinate input surface is detected, and in the scaling step, the size of the drawing pattern is enlarged or reduced according to the pressure detected in the pressure detection step, and the moving direction is calculated. In the step, the moving direction of the coordinate input means is calculated based on the coordinate values sequentially detected in the coordinate value detecting step, and in the drawing pattern rotating step, a direction opposite to the moving direction calculated in the moving direction calculating step is calculated. In the distance interval calculation step, the distance interval between adjacent coordinate values sequentially detected in the coordinate value detection step is calculated, and in the rotation control step, the distance is calculated. The rotation amount of the drawing pattern is reduced by controlling the rotation processing in the drawing pattern rotation step based on the distance interval of the coordinate values calculated in the interval calculation step, and in the drawing step, the rotation is performed through the drawing pattern rotation step or the rotation control step. The drawing pattern that has been enlarged or reduced through the scaling process is sequentially drawn at the coordinate position detected in the coordinate value detection process, so the drawing pattern changes direction slowly at the corners of the character or line diagram to be drawn. This makes it possible to reproduce natural brushstroke drawing with a good texture using a tablet.
[0133]
In the brush writing method according to the present invention, in the turning determination step, it is determined whether or not the moving direction calculated in the moving direction calculating step has suddenly turned. However, in the pattern shortening step, when it is determined in the turning determination step that the moving direction is suddenly turned, the length of the drawing pattern is shortened by a predetermined number of drawings or a predetermined drawing distance. A drawing pattern that has been rotated through a pattern rotation process and a rotation control process, enlarged or reduced through a scaling process, and shortened in length through a pattern shortening process is sequentially drawn at the coordinate positions detected in the coordinate value detection process. This prevents unnecessary projection drawing due to drawing patterns in steep turn-back drawing, such as “splash”, so that a natural brushstroke drawing can be reproduced with a good texture using a tablet. To become.
[0134]
According to a brushstroke drawing method of the present invention (claim 15), in the brushstroke drawing method according to claim 13 or 14, the drawing color becomes lighter as the distance from a predetermined pixel as a center of the pixels constituting the drawing pattern increases. A drawing pattern is composed of a plurality of gray-scale images, and in the gray-scale image adjusting step, the gray-scale image is adjusted according to the pressure detected in the pressure detecting step and / or according to the distance interval of the coordinate values determined in the distance interval calculating step. The number and / or the size of the grayscale image and / or the grayscale of the grayscale image are adjusted, and in the drawing process, the drawing pattern adjusted through the grayscale image adjustment process is further drawn, so that a faint expression is possible. Thus, a natural brushstroke drawing can be reproduced with a good texture using a tablet.
[0135]
Also, in the brush writing method according to the present invention (claim 16), in the brush writing method according to claim 13, 14, or 15, in the stopping determination step, the coordinate input is performed based on the coordinate values detected in the coordinate value detecting step. It is determined whether or not the means is stopped, and in the smoothing step, when it is determined that the coordinate input means is stopped in the stop determination step, a smoothing process is performed on the drawing pattern, and in the drawing step, Since the drawing pattern that has been smoothed through the smoothing process is drawn, a blurred expression can be realized, whereby a natural brush drawing can be reproduced with a good texture using a tablet.
[0136]
Also, in the brush writing method according to the present invention (claim 17), in the brush writing method according to claim 16, in the stop count step, the number of times the coordinate input means stays at the same place in the stop determination step is counted. In the smoothing control step, the diffusion parameter of the smoothing processing is increased by controlling the smoothing processing in the smoothing step in accordance with the number counted in the stationary number counting step. In the drawing step, the smoothing control is further performed. Since the smoothed drawing pattern is drawn under the control of the process, a dynamic blurring expression can be performed, and thereby, a natural brushstroke drawing can be reproduced with good texture using a tablet.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an example of a general configuration of a brush writing apparatus according to the present invention.
FIG. 2 is an explanatory diagram showing a configuration example of a tablet (tablet plate and tablet pen).
FIG. 3 is a diagram illustrating an external configuration of a liquid crystal pen tablet in which a coordinate input surface and a display device are integrally formed.
FIG. 4 is an explanatory diagram showing an example of a hardware configuration of the brush drawing apparatus of the present invention.
FIG. 5 is an explanatory diagram showing an example of a functional configuration that governs a trajectory of a brush drawing in the brush drawing apparatus of the present embodiment.
FIG. 6 is an explanatory diagram showing a relationship between a drawing pattern and a writing pressure (pressure value).
FIG. 7 is an explanatory diagram for defining variables for creating a drawing pattern.
FIG. 8 shows the relationship between the direction θ of the drawing pattern and the moving direction of the tablet pen.
FIG. 9 is a drawing conceptual diagram showing an unnatural projection drawing in a corner and the direction of a drawing pattern when inertia is controlled.
FIG. 10 is a diagram illustrating an example of an unnatural projection drawing that appears when the tablet pen is rapidly turned.
FIG. 11 is an explanatory diagram showing an example of a functional configuration of the brush drawing apparatus according to the present embodiment that changes the expression in the drawing pattern.
FIG. 12 is a diagram illustrating an example of a drawing pattern used in a brush drawing apparatus and a grayscale image (enlarged view) inside the drawing pattern.
FIG. 13 is a diagram illustrating a state in which a smoothing process is sequentially performed on a drawing pattern and a blur is propagated.
FIG. 14 is a diagram showing a shadow pattern and a drawing example.
FIG. 15 is a diagram illustrating a drawing example of a brush drawing device.
FIG. 16 is a diagram showing examples of writing brush strokes in various drawing modes.
FIG. 17 is a table displaying parameters of various drawing modes shown in FIG. 16;
FIG. 18 is a flowchart illustrating a processing flow of the brush drawing apparatus.
FIG. 19 is a diagram illustrating an example of a screen configuration when a processing result of a computer program is displayed on a display device.
FIG. 20 is a diagram illustrating an example of a screen configuration when a processing result of a computer program is displayed on a display device.
FIG. 21 is a diagram illustrating an example of a screen configuration when a processing result of a computer program is displayed on a display device.
FIG. 22 is a diagram illustrating an example of a screen configuration when a processing result of a computer program is displayed on a display device.
FIG. 23 is a diagram illustrating an example of a screen configuration when a processing result of a computer program is displayed on a display device.
FIG. 24 is a diagram illustrating an example of a screen configuration when a processing result of a computer program is displayed on a display device.
FIG. 25 is a diagram illustrating an example of a base of an image sheet.
FIG. 26 is a diagram illustrating an example of a base of a canvas.
FIG. 27 is a diagram showing an example of a setting screen for customizing the size of a drawing pattern.
FIG. 28 is a diagram showing an example of a setting screen for customizing a grayscale image or the like.
FIG. 29 is a diagram showing an example of a setting screen for customizing ink (ink).
FIG. 30 is a diagram showing an example of a setting screen for customizing density and contrast.
FIG. 31 is a diagram showing an example of a setting screen for customizing the amount of permeation and delay control.
[Explanation of symbols]
100mm brush writing device
101 main unit
102mm tablet board
103 tablet pen
104 display device
105 keyboard
106 mouse
121 coordinate input surface
122 pen stand
123 transmission line
131 pen tip
132 Eraser
133,134 side switch
150 tablet
401 CPU
402 @ ROM
403 RAM
404 Hard Disk (HD)
405 graphics card
441 $ OS
442 brush writing software
443 driver software
501 Coordinate input section
502 Coordinate value detector
503 pressure detector
504 drawing pattern scaling section
505 ° moving direction calculation unit
506 drawing pattern rotation unit
507 distance interval calculation unit
508 ° rotation control unit
509 Turn judgment unit
510 drawing pattern shortening unit
511 drawing unit
512 gradation image adjustment unit
513 Stop judgment unit
514 ° smoothing unit
515 Stop count counter
516 smoothing control unit

Claims (17)

A brush drawing device that includes a tablet having a coordinate input surface and coordinate input means for inputting coordinates with respect to the coordinate input surface, and performs drawing according to a locus of a drawing pattern that is a basic shape of drawing.
Coordinate value detecting means for detecting the coordinate value of the coordinates input by the coordinate input means at predetermined time intervals,
Pressure detection means for detecting pressure when the coordinate input means is inputting coordinates with respect to the coordinate input surface,
Scaling means for expanding or reducing the size of the drawing pattern according to the pressure detected by the pressure detecting means,
Moving direction calculating means for calculating a moving direction of the coordinate input means based on the coordinate values sequentially detected by the coordinate value detecting means,
Drawing pattern rotating means for rotating the drawing pattern so that the brush tip portion of the drawing pattern faces in the direction opposite to the moving direction calculated by the moving direction calculating means;
Distance interval calculating means for calculating adjacent distance intervals of coordinate values sequentially detected by the coordinate value detecting means,
A rotation control unit that controls the drawing pattern rotation unit based on the distance interval of the coordinate values calculated by the distance interval calculation unit, and reduces the rotation amount of the drawing pattern,
Drawing means for sequentially drawing drawing patterns rotated by the drawing pattern rotating means or the rotation control means and enlarged or reduced by the scaling means, at coordinate positions detected by the coordinate value detecting means,
A brush drawing device comprising: Turn determining means for determining whether or not the moving direction calculated by the moving direction calculating means has suddenly turned,
When it is determined that the moving direction is suddenly turned by the turning determination unit, a pattern shortening unit that shortens the length of the drawing pattern by a predetermined drawing number or a predetermined drawing distance,
With
The drawing unit is a drawing pattern rotated by the drawing pattern rotation unit or the rotation control unit, enlarged or reduced by the scaling unit, and reduced in length by the pattern shortening unit, by the coordinate value detection unit. 2. The writing brush drawing device according to claim 1, wherein drawing is sequentially performed at the detected coordinate positions. A drawing pattern is constituted by a plurality of grayscale images in which the drawing color becomes lighter as the distance increases with the predetermined pixel as a center,
According to the pressure detected by the pressure detecting means and / or the distance interval of the coordinate value determined by the distance interval calculating means, the number of the grayscale images and / or the size of the grayscale image and / or the grayscale A gray-scale image adjusting means for adjusting the gray scale of the image,
3. The apparatus according to claim 1, wherein the drawing unit further draws a drawing pattern adjusted by the grayscale image adjusting unit. 4. 4. The brushstroke drawing device according to claim 3, wherein the drawing pattern is constituted by an image obtained by applying a smoothing filter to a black dot image randomly shaken in the drawing pattern. 5. Stop determination means for determining whether or not the coordinate input means is stopped based on the coordinate value detected by the coordinate value detection means,
A smoothing unit that performs a smoothing process on the drawing pattern when the coordinate input unit is determined to be stationary by the stationary determination unit;
With
5. The apparatus according to claim 1, wherein the drawing unit further draws a drawing pattern smoothed by the smoothing unit. 6. A stop count counting unit that counts the number of times the coordinate input unit is determined to be stopped at the same place by the stop determination unit,
According to the number of times counted by the stationary number counting means, smoothing control means to control the smoothing means to increase the diffusion parameter of the smoothing process,
With
The brush drawing apparatus according to claim 5, wherein the drawing means further draws a smoothed drawing pattern under the control of the smoothing control means. A program for drawing a drawing pattern, which is a basic shape of drawing, according to the locus, using an output signal from a tablet having a coordinate input surface and coordinate input means for inputting coordinates to the coordinate input surface,
Computer
Coordinate value detecting means for detecting the coordinate value of the coordinates input by the coordinate input means at predetermined time intervals,
Pressure detection means for detecting pressure when the coordinate input means is inputting coordinates with respect to the coordinate input surface,
Scaling means for expanding or reducing the size of the drawing pattern according to the pressure detected by the pressure detecting means,
Moving direction calculating means for calculating a moving direction of the coordinate input means based on the coordinate values sequentially detected by the coordinate value detecting means,
Drawing pattern rotating means for rotating the drawing pattern so that the brush tip portion of the drawing pattern faces in the direction opposite to the moving direction calculated by the moving direction calculating means;
Distance interval calculating means for calculating adjacent distance intervals of coordinate values sequentially detected by the coordinate value detecting means,
A rotation control unit that controls the drawing pattern rotation unit based on the distance interval of the coordinate values calculated by the distance interval calculation unit, and reduces the rotation amount of the drawing pattern,
The drawing pattern rotating means or the rotation control means and functioning as a drawing means for sequentially drawing the drawing pattern enlarged or reduced by the scaling means at a coordinate position detected by the coordinate value detecting means. And a brush drawing program. In addition, the computer
Turn determining means for determining whether or not the moving direction calculated by the moving direction calculating means has suddenly turned,
When it is determined that the moving direction is suddenly turned by the turning determination means, the function as a pattern shortening means for shortening the length of the drawing pattern by a predetermined number of drawing or a predetermined drawing distance,
As the drawing means, the drawing pattern rotated by the drawing pattern rotation means or the rotation control means, enlarged or reduced by the scaling means, and reduced in length by the pattern shortening means, by the coordinate value detection means 8. The program according to claim 7, wherein drawing is performed sequentially at the detected coordinate positions. A drawing pattern is constituted by a plurality of grayscale images in which the drawing color becomes lighter as the distance increases with the predetermined pixel as a center,
In addition, the computer
According to the pressure detected by the pressure detecting means and / or the distance interval of the coordinate value determined by the distance interval calculating means, the number of the grayscale images and / or the size of the grayscale image and / or the grayscale Function as a grayscale image adjustment means for adjusting the grayscale of the image,
9. The writing brush drawing program according to claim 7, wherein the drawing means further functions to draw the drawing pattern adjusted by the grayscale image adjusting means. The brushstroke drawing program according to claim 9, wherein the drawing pattern is configured by an image obtained by applying a smoothing filter to a black spot image randomly shaken in the drawing pattern. In addition, the computer
Stop determination means for determining whether or not the coordinate input means is stopped based on the coordinate value detected by the coordinate value detection means,
When it is determined that the coordinate input means is stopped by the stop determination means, to function as a smoothing means for performing a smoothing process on the drawing pattern,
The program according to any one of claims 7 to 10, wherein the drawing means further functions to draw the drawing pattern smoothed by the smoothing means. In addition, the computer
A stop count counting unit that counts the number of times the coordinate input unit is determined to be stopped at the same place by the stop determination unit,
According to the number counted by the number-of-stops counting means, according to the smoothing control means to control the smoothing means to increase the diffusion parameter of the smoothing process,
12. The writing brush drawing program according to claim 11, wherein the drawing means further functions so as to draw a smoothed drawing pattern under the control of the smoothing control means. A brushstroke drawing method applied to a brushstroke drawing device including a tablet having a coordinate input surface and coordinate input means for inputting coordinates with respect to the coordinate input surface, and performing drawing in accordance with a locus of a drawing pattern which is a basic shape of drawing. hand,
A coordinate value detecting step of detecting a coordinate value of the coordinates input by the coordinate input means at predetermined time intervals,
A pressure detection step of detecting pressure when coordinates are input to the coordinate input surface in the coordinate input step,
An enlargement / reduction step of enlarging or reducing the size of the drawing pattern according to the pressure detected in the pressure detection step;
A moving direction calculating step of calculating a moving direction of the coordinate input means based on the coordinate values sequentially detected in the coordinate value detecting step;
A drawing pattern rotation step of rotating the drawing pattern so that the tip of the drawing pattern is oriented in a direction opposite to the movement direction calculated in the movement direction calculation step;
A distance interval calculating step of calculating an adjacent distance interval of the coordinate values sequentially detected in the coordinate value detecting step,
A rotation control step of controlling a rotation process in the drawing pattern rotation step based on the distance interval of the coordinate value in the distance interval calculation step to reduce the rotation amount of the drawing pattern;
A drawing step of sequentially drawing a drawing pattern rotated through the drawing pattern rotation step or the rotation control step and enlarged or reduced through the enlargement / reduction step, at a coordinate position detected in the coordinate value detection step;
A brushstroke drawing method comprising: A turning determination step of determining whether or not the moving direction calculated in the moving direction calculation step has suddenly turned;
A pattern shortening step of shortening the length of the drawing pattern by a predetermined drawing number or a predetermined drawing distance, when it is determined that the moving direction is suddenly turned in the turning determination step;
Including
In the drawing step, a drawing pattern rotated through the drawing pattern rotation step or the rotation control step, enlarged or reduced through the enlargement / reduction step, and reduced in length through the pattern shortening step is represented by the coordinate value. 14. The brushstroke drawing method according to claim 13, wherein drawing is sequentially performed at the coordinate positions detected in the detecting step. A drawing pattern is constituted by a plurality of grayscale images in which the drawing color becomes lighter as the distance increases with the predetermined pixel as a center,
According to the pressure detected in the pressure detecting step and / or the distance interval of the coordinate value determined in the distance interval calculating step, the number of the grayscale images and / or the size of the grayscale image and / or the grayscale Including a grayscale image adjustment step of adjusting the grayscale of the image,
15. The brushstroke drawing method according to claim 13, wherein in the drawing step, a drawing pattern adjusted through the grayscale image adjustment step is further drawn. A stop determination step of determining whether the coordinate input unit is stopped based on the coordinate values detected in the coordinate value detection step,
When the coordinate input means is determined to be stationary in the stationary determination step, a smoothing step of performing a smoothing process on the drawing pattern,
Including
16. The brushstroke drawing method according to claim 13, wherein the drawing step further draws a drawing pattern smoothed through the smoothing step. A stop count step of counting the number of times the coordinate input means is determined to be stopped at the same place in the stop determination step,
According to the number counted in the number-of-stops counting step, a smoothing control step of controlling a smoothing process in the smoothing process to increase a diffusion parameter of the smoothing process,
Including
17. The brushstroke drawing method according to claim 16, wherein, in the drawing step, a drawing pattern smoothed under the control of the smoothing control step is further drawn.

Images