Swing/NimbusFilledSlider のバックアップ(No.12)

UIDefaults d = new UIDefaults();
d.put("Slider:SliderTrack[Enabled].backgroundPainter", new Painter<JSlider>() {
  @Override public void paint(Graphics2D g, JSlider c, int w, int h) {
    int arc = 10;
    int trackHeight = 8;
    int trackWidth = w - 2;
    int fillTop = 4;
    int fillLeft = 1;

    g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                       RenderingHints.VALUE_ANTIALIAS_ON);
    g.setStroke(new BasicStroke(1.5f));
    g.setColor(Color.GRAY);
    g.fillRoundRect(fillLeft, fillTop, trackWidth, trackHeight, arc, arc);

    int fillBottom = fillTop + trackHeight;
    int fillRight  = xPositionForValue(c, new Rectangle(
        fillLeft, fillTop, trackWidth, fillBottom - fillTop));

    g.setColor(Color.ORANGE);
    g.fillRect(
        fillLeft + 1, fillTop + 1, fillRight - fillLeft, fillBottom - fillTop);

    g.setColor(Color.WHITE);
    g.drawRoundRect(fillLeft, fillTop, trackWidth, trackHeight, arc, arc);
  }

  // @see javax/swing/plaf/basic/BasicSliderUI#xPositionForValue(int value)
  protected int xPositionForValue(JSlider slider, Rectangle trackRect) {
    int value = slider.getValue();
    int min = slider.getMinimum();
    int max = slider.getMaximum();
    int trackLength = trackRect.width;
    double valueRange = (double) max - (double) min;
    double pixelsPerValue = (double) trackLength / valueRange;
    int trackLeft = trackRect.x;
    int trackRight = trackRect.x + trackRect.width - 1;
    int xPosition;

    xPosition = trackLeft;
    xPosition += Math.round(pixelsPerValue * ((double) value - min));

    xPosition = Math.max(trackLeft, xPosition);
    xPosition = Math.min(trackRight, xPosition);

    return xPosition;
  }
});

JSlider slider = new JSlider();
slider.putClientProperty("Nimbus.Overrides", d);