ImageIconCanvas.java

/*
  ImageIconCanvas.java

  (c) 2011-2013 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.events.PaintEvent;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.layout.GridData;

/**
 * An image, which is allowed to be transparent and drawn on a bar.
 * @author ejs
 *
 */
public abstract class ImageIconCanvas extends ImageBarChild {


	protected ImageIconInfo imageIconInfo;
	protected Rectangle bounds;
	protected final IImageProvider imageProvider;
	protected int invAlpha;
	
	public ImageIconCanvas(IImageCanvas parentDrawer, int style, 
			IImageProvider imageProvider, int iconIndex, String tooltip) {
		super(parentDrawer,  style /*| SWT.NO_BACKGROUND*/);
		
		this.imageProvider = imageProvider;
		
		if (imageProvider != null)
			imageIconInfo = new ImageIconInfo(imageProvider);
		else
			imageIconInfo = null;
		
		setLayout(new FillLayout());
		
		if (tooltip != null)
			setToolTipText(tooltip);
		
		setIconIndex(iconIndex);
	}
	
	public void setIconIndex(int iconIndex) {
		
		GridData data;
		if (imageIconInfo != null) {
			imageIconInfo.setIconIndex(iconIndex);
			bounds = imageIconInfo.getBounds();
			data = new GridData(bounds.width, bounds.height);
			data.grabExcessHorizontalSpace = false;
			data.grabExcessVerticalSpace = false;
		} else {
			bounds = null;
			data = GridDataFactory.fillDefaults().grab(true, false).create();
		}
		setLayoutData(data);
		redraw();
	}


	protected void doPaint(PaintEvent e) {
		super.doPaint(e);
		drawImage(e);
	}

	protected void setAlpha(int alpha) {
		this.invAlpha = 255 - alpha;
	}
	/**
	 * @param e
	 */
	protected void drawImage(PaintEvent e) {
		Rectangle drawRect = getBounds();
		try {
			imageProvider.drawImage(e.gc, 255 - invAlpha, drawRect, bounds);
		} catch (IllegalArgumentException e2) {
			e2.printStackTrace();
		}
	}
}