ImageCanvas.java

/*
  ImageCanvas.java

  (c) 2012-2013 Edward Swartz

  All rights reserved. This program and the accompanying materials
  are made available under the terms of the Eclipse Public License v1.0
  which accompanies this distribution, and is available at
  http://www.eclipse.org/legal/epl-v10.html
 */
package v9t9.gui.client.swt.bars;

import org.eclipse.jface.layout.GridDataFactory;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;

import v9t9.gui.client.swt.IFocusRestorer;

/**
 * @author ejs
 *
 */
public class ImageCanvas extends Canvas  implements IImageCanvas{
	protected static final Point ZERO_POINT = new Point(0, 0);
	protected Composite buttonComposite;
	protected final IFocusRestorer focusRestorer;
	protected final boolean smoothResize;
	protected Gradient gradient;
	protected Gradient farGradient;
	protected final boolean isHorizontal;

	protected int edging;
	
	protected int paintOffsX;
	protected int paintOffsY;
	/**
	 * @param parent
	 * @param style
	 */
	public ImageCanvas(Composite parent, int style,
			Gradient gradient, IFocusRestorer focusRestorer, boolean smoothResize) {
		// the bar itself is the full width of the parent
		super(parent, adjustStyle(style));
		this.focusRestorer = focusRestorer;
		this.smoothResize = smoothResize;
		
		this.isHorizontal = (style & SWT.HORIZONTAL) != 0;

		this.edging = (style & SWT.LEFT + SWT.RIGHT + SWT.TOP + SWT.BOTTOM);
		

		this.gradient = gradient;
		this.farGradient = new Gradient(isHorizontal, new int[] { 0, 0 }, new float[] { 1.0f });

		GridDataFactory.swtDefaults()
			.align(isHorizontal ? SWT.FILL : SWT.CENTER, isHorizontal ? SWT.CENTER : SWT.FILL)
			.grab(isHorizontal, !isHorizontal).indent(0, 0)
			.applyTo(this);

		// the inner composite contains the buttons, tightly packed
		buttonComposite = this;
		

		addPaintListener(new PaintListener() {

			public void paintControl(PaintEvent e) {
				if (e.count == 0)
					paintButtonBar(e.gc, ZERO_POINT, getSize());
			}
			
		});
	}

	/**
	 * @param style
	 * @return
	 */
	private static int adjustStyle(int style) {
		style &= ~(SWT.HORIZONTAL + SWT.VERTICAL);
		style |= SWT.NO_RADIO_GROUP | SWT.NO_FOCUS | SWT.NO_BACKGROUND;
//		if (SWT.getPlatform().equals("win32"))
//			style |= SWT.DOUBLE_BUFFERED;
		return style;
	}

	public boolean isHorizontal() {
		return isHorizontal;
	}
	public IFocusRestorer getFocusRestorer() {
		return focusRestorer;
	}

	protected void paintButtonBar(GC gc, Point offset, Point size) {
		int y = size.y;
		int x = size.x;
		Point mySize = getSize();
		if (isHorizontal) {
			y = mySize.y;
		} else {
			x = mySize.x;
		}
		
		gradient.draw(gc, offset.x + paintOffsX, offset.y + paintOffsY, 
				x, y); 
		
		if (isHorizontal) {
			if (paintOffsY != 0) {
				if ((edging & SWT.TOP) != 0) {
					farGradient.draw(gc, offset.x, 
							offset.y + y + paintOffsY,
							x,
							-paintOffsY);
				} else {
					farGradient.draw(gc, offset.x, 
							offset.y,
							x,
							paintOffsY);
					
				}
				
			}
		} else {
			if (paintOffsX != 0) {
				if ((edging & SWT.LEFT) != 0) {
					farGradient.draw(gc, offset.x + x + paintOffsX, 
							offset.y,
							Math.max(0, -paintOffsX),
							y);
				} else {
					farGradient.draw(gc, offset.x, 
							offset.y,
							Math.max(0, paintOffsX),
							y);
					
				}				
			}
		}
	}

	public void drawBackground(GC gc) {
		paintButtonBar(gc, ZERO_POINT, getSize());
	}

	/**
	 * The composite to which to add buttons.
	 * @return
	 */
	public Composite getComposite() {
		return buttonComposite;
	}

	public void redrawAll() {
		redrawAll(this);
	}

	private void redrawAll(Control c) {
		c.redraw();
		if (c instanceof Composite)
			for (Control control : ((Composite) c).getChildren())
				redrawAll(control);
	}

	/* (non-Javadoc)
	 * @see v9t9.gui.client.swt.bars.IImageCanvas#isRetracted()
	 */
	@Override
	public boolean isRetracted() {
		return false;
	}
	
	/* (non-Javadoc)
	 * @see v9t9.gui.client.swt.bars.IImageCanvas#getPaintOffset()
	 */
	@Override
	public Point getPaintOffset() {
		return ZERO_POINT;
	}
}