synthsliderui.java

Mobile 应用程序使用 Java Micro Edition (Java ME) 平台

        int trackBottom = trackRect.y + trackRect.height
            - thumbRect.height / 2 - trackBorder;
        int trackLength = trackBottom - trackTop;
        
        if (yPos <= trackTop) {
            value = drawInverted() ? minValue : maxValue;
        } else if (yPos >= trackBottom) {
            value = drawInverted() ? maxValue : minValue;
        } else {
            int distanceFromTrackTop = yPos - trackTop;
            double valueRange = (double)maxValue - (double)minValue;
            double valuePerPixel = valueRange / (double)trackLength;
            int valueFromTrackTop =
                (int)Math.round(distanceFromTrackTop * valuePerPixel);
            value = drawInverted() ?
                minValue + valueFromTrackTop : maxValue - valueFromTrackTop;
        }
        return value;
    }
  
    /**
     * Returns a value give an x position.  If xPos is past the track at the
     * left or the right it will set the value to the min or max of the
     * slider, depending if the slider is inverted or not.
     */
    public int valueForXPosition(int xPos) {
        int value;
        int minValue = slider.getMinimum();
        int maxValue = slider.getMaximum();
        int trackLeft = trackRect.x + thumbRect.width / 2 + trackBorder;
        int trackRight = trackRect.x + trackRect.width
            - thumbRect.width / 2 - trackBorder;
        int trackLength = trackRight - trackLeft;
        
        if (xPos <= trackLeft) {
            value = drawInverted() ? maxValue : minValue;
        } else if (xPos >= trackRight) {
            value = drawInverted() ? minValue : maxValue;
        } else {
            int distanceFromTrackLeft = xPos - trackLeft;
            double valueRange = (double)maxValue - (double)minValue;
            double valuePerPixel = valueRange / (double)trackLength;
            int valueFromTrackLeft =
                (int)Math.round(distanceFromTrackLeft * valuePerPixel);
            value = drawInverted() ?
                maxValue - valueFromTrackLeft : minValue + valueFromTrackLeft;
        }
        return value;
    }

    protected Dimension getThumbSize() {
        Dimension size = new Dimension();

        if (slider.getOrientation() == JSlider.VERTICAL) {
            size.width = thumbHeight;
            size.height = thumbWidth;
        } else {
            size.width = thumbWidth;
            size.height = thumbHeight;
        }
        return size;
    }

    protected void recalculateIfInsetsChanged() {
        SynthContext context = getContext(slider);
        Insets newInsets = style.getInsets(context, null);
        if (!newInsets.equals(insetCache)) {
            insetCache = newInsets;
            calculateGeometry();
        }
        context.dispose();
    }

    public Region getRegion(JComponent c) {
        return SynthLookAndFeel.getRegion(c);
    }

    public SynthContext getContext(JComponent c) {
        return getContext(c, getComponentState(c));
    }

    public SynthContext getContext(JComponent c, int state) {
        return SynthContext.getContext(SynthContext.class, c,
                            SynthLookAndFeel.getRegion(c), style, state);
    }

    public SynthContext getContext(JComponent c, Region subregion) {
        return getContext(c, subregion, getComponentState(c, subregion));
    }

    private SynthContext getContext(JComponent c, Region subregion, int state) {
        SynthStyle style = null;
        Class klass = SynthContext.class;

        if (subregion == Region.SLIDER_TRACK) {
            style = sliderTrackStyle;
        } else if (subregion == Region.SLIDER_THUMB) {
            style = sliderThumbStyle;
        }
        return SynthContext.getContext(klass, c, subregion, style, state);
    }

    public int getComponentState(JComponent c) {
        return SynthLookAndFeel.getComponentState(c);
    }

    private int getComponentState(JComponent c, Region region) {
        if (region == Region.SLIDER_THUMB && thumbActive &&c.isEnabled()) {
            int state = thumbPressed ? PRESSED : MOUSE_OVER;
            if (c.isFocusOwner()) state |= FOCUSED;
            return state;
        }
        return SynthLookAndFeel.getComponentState(c);
    }

    public void update(Graphics g, JComponent c) {
        SynthContext context = getContext(c);
        SynthLookAndFeel.update(context, g);
        context.getPainter().paintSliderBackground(context,
                          g, 0, 0, c.getWidth(), c.getHeight(),
                          slider.getOrientation());
        paint(context, g);
        context.dispose();
    }

    public void paint(Graphics g, JComponent c) {
        SynthContext context = getContext(c);
        paint(context, g);
        context.dispose();
    }

    public void paint(SynthContext context, Graphics g) {
        recalculateIfInsetsChanged();
        recalculateIfOrientationChanged();
        Rectangle clip = g.getClipBounds();

	if (lastSize == null || !lastSize.equals(slider.getSize())) {
	    calculateGeometry();
        }
        
        if (paintValue) {
            FontMetrics fm = SwingUtilities2.getFontMetrics(slider, g);
            int labelWidth = context.getStyle().getGraphicsUtils(context).
                computeStringWidth(context, g.getFont(), fm,
                    "" + slider.getValue());
            valueRect.x = thumbRect.x + (thumbRect.width - labelWidth) / 2;
            
            // For horizontal sliders, make sure value is not painted
            // outside slider bounds.
            if (slider.getOrientation() == JSlider.HORIZONTAL) {
                if (valueRect.x + labelWidth > contentDim.width) {
                    valueRect.x = contentDim.width - labelWidth;
                }
                valueRect.x = Math.max(valueRect.x, 0);
            }
            
            g.setColor(context.getStyle().getColor(
                    context, ColorType.TEXT_FOREGROUND));
            context.getStyle().getGraphicsUtils(context).paintText(
                    context, g, "" + slider.getValue(), valueRect.x,
                    valueRect.y, -1);
        }
        
        SynthContext subcontext = getContext(slider, Region.SLIDER_TRACK);
        paintTrack(subcontext, g, trackRect);
        subcontext.dispose();

        subcontext = getContext(slider, Region.SLIDER_THUMB);
        paintThumb(subcontext, g, thumbRect);
        subcontext.dispose();

        if (slider.getPaintTicks() && clip.intersects(tickRect)) {
            paintTicks(g);
        }

        if (slider.getPaintLabels() && clip.intersects(labelRect)) {
            paintLabels(g);
        }
    }

    public void paintBorder(SynthContext context, Graphics g, int x,
                            int y, int w, int h) {
        context.getPainter().paintSliderBorder(context, g, x, y, w, h,
                                               slider.getOrientation());
    }

    public void paintThumb(SynthContext context, Graphics g,
            Rectangle thumbBounds)  {        
        int orientation = slider.getOrientation();
        SynthLookAndFeel.updateSubregion(context, g, thumbBounds);
        context.getPainter().paintSliderThumbBackground(context, g,
                             thumbBounds.x, thumbBounds.y, thumbBounds.width,
                             thumbBounds.height, orientation);
        context.getPainter().paintSliderThumbBorder(context, g,
                             thumbBounds.x, thumbBounds.y, thumbBounds.width,
                             thumbBounds.height, orientation);
    }

    public void paintTrack(SynthContext context, Graphics g,
            Rectangle trackBounds) {
        int orientation = slider.getOrientation();
        SynthLookAndFeel.updateSubregion(context, g, trackBounds);
        context.getPainter().paintSliderTrackBackground(context, g,
                trackBounds.x, trackBounds.y, trackBounds.width,
                trackBounds.height, orientation);
        context.getPainter().paintSliderTrackBorder(context, g,
                trackBounds.x, trackBounds.y, trackBounds.width,
                trackBounds.height, orientation);
    }

    public void propertyChange(PropertyChangeEvent e) {
        if (SynthLookAndFeel.shouldUpdateStyle(e)) {
            updateStyle((JSlider)e.getSource());
        }
    }

    //////////////////////////////////////////////////
    /// Track Listener Class
    //////////////////////////////////////////////////
    /**
     * Track mouse movements.
     */
    protected class SynthTrackListener extends TrackListener {

        public void mouseExited(MouseEvent e) {
            setThumbActive(false);
        }

        public void mousePressed(MouseEvent e) {
            super.mousePressed(e);
            setThumbPressed(thumbRect.contains(e.getX(), e.getY()));
        }

        public void mouseReleased(MouseEvent e) {
            super.mouseReleased(e);
            updateThumbState(e.getX(), e.getY(), false);
        }

        public void mouseDragged(MouseEvent e) {
            SynthScrollBarUI ui;
            int thumbMiddle = 0;

            if (!slider.isEnabled()) {
                return;
            }

            currentMouseX = e.getX();
            currentMouseY = e.getY();

            if (!isDragging()) {
                return;
            }

            slider.setValueIsAdjusting(true);

            switch (slider.getOrientation()) {
            case JSlider.VERTICAL:      
                int halfThumbHeight = thumbRect.height / 2;
                int thumbTop = e.getY() - offset;
                int trackTop = trackRect.y;
                int trackBottom = trackRect.y + trackRect.height
                    - halfThumbHeight - trackBorder;
                int vMax = yPositionForValue(slider.getMaximum() -
                    slider.getExtent());

                if (drawInverted()) {
                    trackBottom = vMax;
                    trackTop = trackTop + halfThumbHeight;
                } else {
                    trackTop = vMax;
                }
                thumbTop = Math.max(thumbTop, trackTop - halfThumbHeight);
                thumbTop = Math.min(thumbTop, trackBottom - halfThumbHeight);

                setThumbLocation(thumbRect.x, thumbTop);

                thumbMiddle = thumbTop + halfThumbHeight;
                slider.setValue(valueForYPosition(thumbMiddle));
                break;
            case JSlider.HORIZONTAL:
                int halfThumbWidth = thumbRect.width / 2;
                int thumbLeft = e.getX() - offset;
                int trackLeft = trackRect.x + halfThumbWidth + trackBorder;
                int trackRight = trackRect.x + trackRect.width
                    - halfThumbWidth - trackBorder;
                int hMax = xPositionForValue(slider.getMaximum() -
                    slider.getExtent());

                if (drawInverted()) {
                    trackLeft = hMax;
                } else {
                    trackRight = hMax;
                }
                thumbLeft = Math.max(thumbLeft, trackLeft - halfThumbWidth);
                thumbLeft = Math.min(thumbLeft, trackRight - halfThumbWidth);

                setThumbLocation(thumbLeft, thumbRect.y);

                thumbMiddle = thumbLeft + halfThumbWidth;
                slider.setValue(valueForXPosition(thumbMiddle));
                break;
            default:
                return;
            }

            if (slider.getValueIsAdjusting()) {
                setThumbActive(true);
            }
        }

        public void mouseMoved(MouseEvent e) {
            updateThumbState(e.getX(), e.getY());
        }
    }
}