概要

JTableのセルエディタ、セルレンダラに設定したJCheckBoxのチェックアイコンをJTableの行の高さに応じてリサイズします。

スクリーンショット

Swing/ScaledIcon.png

サンプルコード

class ScaledIcon implements Icon {
  private final Icon icon;
  private final int width;
  private final int height;

  protected ScaledIcon(Icon icon, int width, int height) {
    this.icon = icon;
    this.width = width;
    this.height = height;
  }

  @Override public void paintIcon(Component c, Graphics g, int x, int y) {
    Graphics2D g2 = (Graphics2D) g.create();
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    g2.translate(x, y);
    double sx = width / (double) icon.getIconWidth();
    double sy = height / (double) icon.getIconHeight();
    g2.scale(sx, sy);
    icon.paintIcon(c, g2, 0, 0);
    g2.dispose();
  }

  @Override public int getIconWidth() {
    return width;
  }

  @Override public int getIconHeight() {
    return height;
  }
}

class CheckBoxIcon implements Icon {
  @Override public void paintIcon(Component c, Graphics g, int x, int y) {
    if (!(c instanceof AbstractButton)) {
      return;
    }
    Graphics2D g2 = (Graphics2D) g.create();
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    g2.translate(x, y);
    g2.setPaint(Color.DARK_GRAY);
    float s = Math.min(getIconWidth(), getIconHeight()) * .05f;
    float w = getIconWidth() - s - s;
    float h = getIconHeight() - s - s;
    float gw = w / 8f;
    float gh = h / 8f;
    g2.setStroke(new BasicStroke(s));
    g2.draw(new Rectangle2D.Float(s, s, w, h));
    AbstractButton b = (AbstractButton) c;
    if (b.getModel().isSelected()) {
      g2.setStroke(new BasicStroke(3f * s));
      Path2D p = new Path2D.Float();
      p.moveTo(x + 2f * gw, y + .5f * h);
      p.lineTo(x + .4f * w, y + h - 2f * gh);
      p.lineTo(x + w - 2f * gw, y + 2f * gh);
      g2.draw(p);
    }
    g2.dispose();
  }

  @Override public int getIconWidth() {
    return 1000;
  }

  @Override public int getIconHeight() {
    return 1000;
  }
}
View in GitHub: Java, Kotlin

解説

  • CheckBoxIcon
    • Path2Dで作成したチェック図形を描画するサイズ1000x1000pxIconを作成
  • ScaledIcon
    • Icon#paintIcon(...)をオーバーライドしてGraphics2D.scale(double, double)で指定した値(このサンプルでは行の高さの40px)まで縮小して描画する別Iconでラップ
  • セルエディタ、セルレンダラ用のJCheckBoxJCheckBox#setIcon(...)で設定
    • JTable#prepareRenderer(...)JTable#prepareEditor(...)をオーバーライドして上記のScaledIconを行の高さに調整して設定
JTable table = new JTable(model) {
  private final Insets iconIns = new Insets(4, 4, 4, 4);
  private final transient Icon checkIcon = new CheckBoxIcon();

  @Override public Component prepareRenderer(TableCellRenderer renderer, int row, int column) {
    Component c = super.prepareRenderer(renderer, row, column);
    if (c instanceof JCheckBox) {
      int s = getRowHeight(row) - iconIns.top - iconIns.bottom;
      JCheckBox cb = (JCheckBox) c;
      cb.setIcon(new ScaledIcon(checkIcon, s, s));
      cb.setBorderPainted(false);
    }
    return c;
  }

  @Override public Component prepareEditor(TableCellEditor editor, int row, int column) {
    Component c = super.prepareEditor(editor, row, column);
    if (c instanceof JCheckBox) {
      int s = getRowHeight(row) - iconIns.top - iconIns.bottom;
      JCheckBox cb = (JCheckBox) c;
      cb.setIcon(new ScaledIcon(checkIcon, s, s));
      cb.setBackground(getSelectionBackground());
    }
    return c;
  }
};
table.setRowHeight(40);
table.setSelectionBackground(Color.WHITE);

参考リンク

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