---
category: swing
folder: TextOnPath
title: Shape上に文字列を配置する
tags: [Font, GlyphVector, Shape, Path2D, FlatteningPathIterator]
author: aterai
pubdate: 2024-09-23T07:31:47+09:00
description: Path2Dなどの曲線上に添うよう文字列を移動・回転して配置します。
image: https://drive.google.com/uc?id=1kBK9anV1EnAjXes9rjN3o57Cyk_Qinnw
hreflang:
href: https://java-swing-tips.blogspot.com/2024/10/move-and-rotate-strings-to-place-them.html
lang: en
---
* 概要 [#summary]
`Path2D`などの曲線上に添うよう文字列を移動・回転して配置します。
#download(https://drive.google.com/uc?id=1kBK9anV1EnAjXes9rjN3o57Cyk_Qinnw)
* サンプルコード [#sourcecode]
#code(link){{
public static Shape createTextOnPath(Shape shape, GlyphVector gv) {
double[] points = new double[6];
Point2D prevPt = new Point2D.Double();
double nextAdvance = 0d;
double next = 0d;
Path2D result = new Path2D.Double();
int length = gv.getNumGlyphs();
int idx = 0;
PathIterator pi = new FlatteningPathIterator(
shape.getPathIterator(null), 1d);
while (idx < length && !pi.isDone()) {
switch (pi.currentSegment(points)) {
case PathIterator.SEG_MOVETO:
result.moveTo(points[0], points[1]);
prevPt.setLocation(points[0], points[1]);
nextAdvance = gv.getGlyphMetrics(idx).getAdvance() * .5;
next = nextAdvance;
break;
case PathIterator.SEG_LINETO:
double dx = points[0] - prevPt.getX();
double dy = points[1] - prevPt.getY();
double distance = Math.hypot(dx, dy);
if (distance >= next) {
double r = 1d / distance;
double angle = Math.atan2(dy, dx);
while (idx < length && distance >= next) {
double x = prevPt.getX() + next * dx * r;
double y = prevPt.getY() + next * dy * r;
double advance = nextAdvance;
nextAdvance = getNextAdvance(gv, idx, length);
AffineTransform at = AffineTransform.getTranslateInstance(x, y);
at.rotate(angle);
Point2D pt = gv.getGlyphPosition(idx);
at.translate(-pt.getX() - advance, -pt.getY());
Shape s = gv.getGlyphOutline(idx);
result.append(at.createTransformedShape(s), false);
next += advance + nextAdvance;
idx++;
}
}
next -= distance;
prevPt.setLocation(points[0], points[1]);
break;
default:
}
pi.next();
}
return result;
}
}}
* 解説 [#explanation]
- `Arc2D`で作成した曲線を[https://docs.oracle.com/javase/jp/8/docs/api//java/awt/geom/FlatteningPathIterator.html FlatteningPathIterator]で平坦化(パスを直線に変更)した`PathIterator`に変換
-- [[FlatteningPathIteratorでShape上の点を取得する>Swing/FlatteningPathIterator]]
- 文字列を`Font#createGlyphVector(...)`で`GlyphVector`に変換
- `GlyphVector#getGlyphOutline(...)`で文字のアウトライン図形を取得
- `Math.hypot(dx, dy)`で移動距離、`Math.atan2(dy, dx)`で回転角度を取得して`AffineTransform`で文字のアウトライン図形を変換
-- [http://www.jhlabs.com/java/java2d/strokes/ Fun with Java2D - Strokes]の[http://www.jhlabs.com/java/java2d/strokes/ShapeStroke.java ShapeStroke.java]から繰り返しなし、文字間拡張なしを参考
- `Path2D#append(...)`で変換した文字アウトラインを追加して、`Shape`上に文字列を配置した`Path2D`を生成
* 参考リンク [#reference]
- [http://www.jhlabs.com/java/java2d/strokes/ Fun with Java2D - Strokes]
- [[FlatteningPathIteratorでShape上の点を取得する>Swing/FlatteningPathIterator]]
* コメント [#comment]
#comment
#comment