概要

水平JSliderの目盛りをトラック上部に表示し、つまみの矢印も上向きに描画するよう変更します。

スクリーンショット

Swing/SliderTicksPosition.png

サンプルコード

class VerticalFlipLayerUI extends LayerUI<JComponent> {
  @Override public void paint(Graphics g, JComponent c) {
    if (c instanceof JLayer) {
      Graphics2D g2 = (Graphics2D) g.create();
      g2.setTransform(getAffineTransform(c.getSize()));
      super.paint(g2, c);
      g2.dispose();
    } else {
      super.paint(g, c);
    }
  }

  @Override public void installUI(JComponent c) {
    super.installUI(c);
    if (c instanceof JLayer) {
      JLayer<?> l = (JLayer<?>) c;
      l.setLayerEventMask(AWTEvent.MOUSE_EVENT_MASK | AWTEvent.MOUSE_MOTION_EVENT_MASK);
    }
  }

  @Override public void uninstallUI(JComponent c) {
    if (c instanceof JLayer) {
      ((JLayer<?>) c).setLayerEventMask(0);
    }
    super.uninstallUI(c);
  }

  @Override public void eventDispatched(AWTEvent e, JLayer<? extends JComponent> l) {
    if (e instanceof MouseEvent) {
      MouseEvent me = (MouseEvent) e;
      Point2D pt = me.getPoint();
      try {
        pt = getAffineTransform(l.getSize()).inverseTransform(pt, null);
      } catch (NoninvertibleTransformException ex) {
        ex.printStackTrace();
        UIManager.getLookAndFeel().provideErrorFeedback(me.getComponent());
      }
      // Horizontal: me.translatePoint((int) pt.getX() - me.getX(), 0);
      me.translatePoint(0, (int) pt.getY() - me.getY());
      me.getComponent().repaint();
    }
    super.eventDispatched(e, l);
  }

  private AffineTransform getAffineTransform(Dimension d) {
    AffineTransform at = AffineTransform.getTranslateInstance(0d, d.height);
    at.scale(1d, -1d);
    return at;
  }
}
View in GitHub: Java, Kotlin

解説

  • VerticalFlipLayerUI
    • JLayerを使用して水平JSliderとその内部のMouseEventの上下を反転
    • ラベルの数字も上下反転してしまう
    • Ubuntu 20.04.4 LTSJLayerが表示されない場合がある?
      • このサンプルではBorderLayout.NORTHで表示されてBorderLayout.SOUTHで非表示になる?
  • UpArrowThumbSliderUI
    • BasicSliderUIcalculateTrackRect()calculateTickRect()calculateLabelRect()をオーバーライドしてこの3つの領域の描画位置を入れ替える
    • つまみの矢印はBasicSliderUI#paintThumb()をオーバーライドしてその場で上下反転描画
    • MetalLookAndFeelWindowsLookAndFeelではつまみだけ反転するのは難しい?
class UpArrowThumbSliderUI extends BasicSliderUI {
  protected UpArrowThumbSliderUI(JSlider slider) {
    super(slider);
  }

  @Override protected void calculateTrackRect() {
    if (slider.getOrientation() == SwingConstants.HORIZONTAL) {
      int centerSpacing = thumbRect.height;
      if (slider.getPaintTicks()) {
        centerSpacing -= getTickLength();
      }
      if (slider.getPaintLabels()) {
        centerSpacing -= getHeightOfTallestLabel();
      }
      trackRect.x = contentRect.x + trackBuffer;
      trackRect.y = contentRect.y + (contentRect.height + centerSpacing + 1) / 2;
      trackRect.width = contentRect.width - (trackBuffer * 2);
      trackRect.height = thumbRect.height;
    } else {
      super.calculateTrackRect();
    }
  }

  @Override protected void calculateTickRect() {
    if (slider.getOrientation() == SwingConstants.HORIZONTAL) {
      tickRect.x = trackRect.x;
      // tickRect.y = trackRect.y + trackRect.height;
      tickRect.y = trackRect.y;
      tickRect.width = trackRect.width;
      tickRect.height = slider.getPaintTicks() ? getTickLength() : 0;
    } else {
      super.calculateTickRect();
    }
  }

  @Override protected void calculateLabelRect() {
    if (slider.getPaintLabels()) {
      if (slider.getOrientation() == SwingConstants.HORIZONTAL) {
        labelRect.width = tickRect.width + (trackBuffer * 2);
        labelRect.height = getHeightOfTallestLabel();
        labelRect.x = tickRect.x - trackBuffer;
        labelRect.y = tickRect.y - labelRect.height;
      } else {
        super.calculateLabelRect();
      }
    } else {
      if (slider.getOrientation() == SwingConstants.HORIZONTAL) {
        labelRect.x = tickRect.x;
        labelRect.y = tickRect.y; // + tickRect.height;
        labelRect.width = tickRect.width;
        labelRect.height = 0;
      } else {
        super.calculateLabelRect();
      }
    }
  }

  @Override public void paintThumb(Graphics g) {
    if (slider.getOrientation() == SwingConstants.HORIZONTAL) {
      Graphics2D g2 = (Graphics2D) g.create();
      g2.translate(0, contentRect.y + contentRect.height + thumbRect.height);
      g2.scale(1d, -1d);
      super.paintThumb(g2);
      g2.dispose();
    } else {
      super.paintThumb(g);
    }
  }
}

参考リンク

  • JSliderの順序を反転
    • 垂直JSliderの目盛りをデフォルトの右側から左側に変更する場合はJSlider#setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT)が使用可能

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