JTextComponentの選択ハイライトを角丸で描画する

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Summary

JTextComponentの選択ハイライトや検索ハイライトなどを角丸で描画するHighlightPainterを作成します。

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Source Code Examples

class RoundedSelectionHighlightPainter extends DefaultHighlightPainter {
  protected RoundedSelectionHighlightPainter() {
    super(null);
  }

  @Override public void paint(
        Graphics g, int offs0, int offs1, Shape bounds, JTextComponent c) {
    Rectangle alloc = bounds.getBounds();
    try {
      // --- determine locations ---
      TextUI mapper = c.getUI();
      Rectangle p0 = mapper.modelToView(c, offs0);
      Rectangle p1 = mapper.modelToView(c, offs1);
      // --- render ---
      Graphics2D g2 = (Graphics2D) g.create();
      g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                          RenderingHints.VALUE_ANTIALIAS_ON);
      Color color = getColor();
      if (color == null) {
        g2.setColor(c.getSelectionColor().brighter());
      } else {
        g2.setColor(color);
      }
      if (p0.y == p1.y) { // same line, render a rectangle
        Rectangle r = p0.union(p1);
        g2.fillRoundRect(r.x, r.y, r.width, r.height, 5, 5);
      } else { // different lines
        int p0ToMarginWidth = alloc.x + alloc.width - p0.x;
        g2.fillRoundRect(p0.x, p0.y, p0ToMarginWidth, p0.height, 5, 5);
        g2.fillRect(p0.x + 5, p0.y, p0ToMarginWidth - 5, p0.height);
        int maxY = p0.y + p0.height;
        if (maxY != p1.y) {
          g2.fillRect(alloc.x, maxY, alloc.width, p1.y - maxY);
        }
        g2.fillRect(alloc.x, p1.y, p1.x - alloc.x - 5, p1.height);
        g2.fillRoundRect(alloc.x, p1.y, p1.x - alloc.x, p1.height, 5, 5);
      }
      g2.dispose();
    } catch (BadLocationException ex) {
      // can't render
      Logger.getGlobal().severe(ex::getMessage);
    }
  }

  @Override public Shape paintLayer(
        Graphics g, int offs0, int offs1, Shape bounds,
        JTextComponent c, View view) {
    Graphics2D g2 = (Graphics2D) g.create();
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                        RenderingHints.VALUE_ANTIALIAS_ON);
    Color color = getColor();
    if (color == null) {
      g2.setColor(c.getSelectionColor());
    } else {
      g2.setColor(color);
    }
    Rectangle r = null;
    if (offs0 == view.getStartOffset() && offs1 == view.getEndOffset()) {
      // Contained in view, can just use bounds.
      if (bounds instanceof Rectangle) {
        r = (Rectangle) bounds;
      } else {
        r = bounds.getBounds();
      }
    } else {
      // Should only render part of View.
      try {
        // --- determine locations ---
        Shape shape = view.modelToView(
            offs0, Position.Bias.Forward, offs1, Position.Bias.Backward, bounds);
        r = shape instanceof Rectangle ? (Rectangle) shape : shape.getBounds();
      } catch (BadLocationException ex) {
        // can't render
        Logger.getGlobal().severe(ex::getMessage);
      }
    }
    if (r != null) {
      // If we are asked to highlight, we should draw something even
      // if the model-to-view projection is of zero width (6340106).
      r.width = Math.max(r.width, 1);
      g2.fillRoundRect(r.x, r.y, r.width - 1, r.height - 1, 5, 5);
      g2.setColor(c.getSelectionColor().darker());
      g2.drawRoundRect(r.x, r.y, r.width - 1, r.height - 1, 5, 5);
    }
    g2.dispose();
    return r;
  }
}
View in GitHub: Java, Kotlin

Explanation

  • 選択ハイライト: RoundedSelectionHighlightPainter
    • JTextComponentの選択ハイライトを変更と同様に、Caret#getSelectionPainter()メソッドをオーバーライドして選択ハイライトを描画するHighlightPainterを変更
    • DefaultHighlightPainter#paintLayer(...)をオーバーライドしてGraphics#fillRect(...)をGraphics#fillRoundRect(...)に置換して各選択ハイライト領域の角を丸めて描画
    • DefaultHighlighter#setDrawsLayeredHighlights(false)が設定されている場合、DefaultHighlightPainter#paint(...)でハイライトが描画されるので、こちらをオーバーライドして選択ハイライトを角丸に変更
      • 選択が同一行内に収まる場合はGraphics#fillRect(...)をGraphics#fillRoundRect(...)に置換して角丸矩形を描画
      • 選択が複数行に渡る場合は先頭と末尾の選択行領域を描画するGraphics#fillRect(...)をGraphics#fillRoundRect(...)に置換して角丸矩形を描画
  • 検索ハイライト: RoundedHighlightPainter
    • JTextAreaの検索ハイライトに縁を描画すると同様に、Highlighter#addHighlight(...)メソッドで検索にヒットした文字列のハイライトを描画するHighlightPainterを指定
    • 選択ハイライトと同様にDefaultHighlighter#setDrawsLayeredHighlights(...)の設定を考慮してDefaultHighlightPainter#paintLayer(...)とDefaultHighlightPainter#paint(...)の両方をオーバーライドしてハイライトを角丸で描画
class RoundedHighlightPainter extends DefaultHighlightPainter {
  protected RoundedHighlightPainter() {
    super(new Color(0x0, true));
  }

  @Override public void paint(
      Graphics g, int offs0, int offs1, Shape bounds, JTextComponent c) {
    try {
      Graphics2D g2 = (Graphics2D) g.create();
      g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                          RenderingHints.VALUE_ANTIALIAS_ON);
      TextUI mapper = c.getUI();
      Rectangle p0 = mapper.modelToView(c, offs0);
      Rectangle p1 = mapper.modelToView(c, offs1);
      if (p0.y == p1.y) { // same line, render a rectangle
        Shape s = makeRoundRectangle(p0.union(p1));
        g2.setColor(Color.PINK);
        g2.fill(s);
        g2.setPaint(Color.RED);
        g2.draw(s);
      } else { // different lines
        Rectangle alloc = bounds.getBounds();
        int p0ToMarginWidth = alloc.x + alloc.width - p0.x;
        g2.setColor(Color.PINK);
        g2.fillRoundRect(p0.x, p0.y, p0ToMarginWidth, p0.height, 5, 5);
        g2.fillRect(p0.x + 5, p0.y, p0ToMarginWidth - 5, p0.height);
        int maxY = p0.y + p0.height;
        if (maxY != p1.y) {
          g2.fillRect(alloc.x, maxY, alloc.width, p1.y - maxY);
        }
        g2.fillRect(alloc.x, p1.y, p1.x - alloc.x - 5, p1.height);
        g2.fillRoundRect(alloc.x, p1.y, p1.x - alloc.x, p1.height, 5, 5);
      }
      g2.dispose();
    } catch (BadLocationException ex) {
      // can't render
      Logger.getGlobal().severe(ex::getMessage);
    }
  }

  @Override public Shape paintLayer(
      Graphics g, int offs0, int offs1, Shape bounds,
      JTextComponent c, View view) {
    Shape s = super.paintLayer(g, offs0, offs1, bounds, c, view);
    if (s instanceof Rectangle) {
      Graphics2D g2 = (Graphics2D) g.create();
      g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                          RenderingHints.VALUE_ANTIALIAS_ON);
      g2.setPaint(Color.ORANGE);
      Shape r = makeRoundRectangle(s.getBounds());
      g2.fill(r);
      g2.setPaint(Color.RED);
      g2.draw(r);
      g2.dispose();
    }
    return s;
  }

  private static RoundRectangle2D makeRoundRectangle(Rectangle r) {
    return new RoundRectangle2D.Float(r.x, r.y, r.width - 1, r.height - 1, 5f, 5f);
  }
}

Reference

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