translucentsimplebackground.java

j2me polish学习的经典代码

//#condition polish.usePolishGui
/*
 * Created on 19-Nov-2004 at 18:34:29.
 * 
 * Copyright (c) 2004-2005 Robert Virkus / Enough Software
 *
 * This file is part of J2ME Polish.
 *
 * J2ME Polish is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * J2ME Polish is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with J2ME Polish; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * 
 * Commercial licenses are also available, please
 * refer to the accompanying LICENSE.txt or visit
 * http://www.j2mepolish.org for details.
 */
package de.enough.polish.ui.backgrounds;

import javax.microedition.lcdui.Graphics;
//#if polish.api.nokia-ui
	import com.nokia.mid.ui.DirectGraphics;
	import com.nokia.mid.ui.DirectUtils;
//#endif

import de.enough.polish.ui.Background;

/**
 * <p>Paints a simple translucent background.</p>
 *
 * <p>Copyright Enough Software 2004, 2005</p>

 * <pre>
 * history
 *        19-Nov-2004 - rob creation
 * </pre>
 * @author Robert Virkus, [e-mail]
 */
public class TranslucentSimpleBackground extends Background {

	private final int argbColor;
	//#ifdef polish.api.nokia-ui
		private final int[] xCoords;
		private final int[] yCoords;
	//#elifdef polish.midp2
		// int MIDP/2.0 the buffer is always used:
		private int[] buffer;
		private int lastWidth;
		//#if polish.Bugs.drawRgbNeedsFullBuffer
			private int lastHeight;
		//#endif
	//#endif

	/**
	 * Creates a new TranslucentBackground
	 * 
	 * @param argbColor the AARRGGBB color with an alpha-channel between 0 and 255.
	 */
	public TranslucentSimpleBackground( int argbColor ) {
		super();
		this.argbColor = argbColor;
		//#if polish.api.nokia-ui
			this.xCoords = new int[4];
			this.xCoords[0] = Integer.MIN_VALUE;
			this.yCoords = new int[4];
			this.yCoords[0] = Integer.MIN_VALUE;
		//#endif
	}

	/* (non-Javadoc)
	 * @see de.enough.polish.ui.Background#paint(int, int, int, int, javax.microedition.lcdui.Graphics)
	 */
	public void paint(int x, int y, int width, int height, Graphics g) {
		//#ifdef polish.api.nokia-ui
			DirectGraphics dg = DirectUtils.getDirectGraphics(g);
			if ( this.xCoords[0] != x || this.xCoords[1] != x + width) {
				this.xCoords[0] = x;
				this.xCoords[1] = x + width;
				this.xCoords[2] = x + width;
				this.xCoords[3] = x;
			}
			if ( this.yCoords[0] != y || this.yCoords[2] != y + height ) {
				this.yCoords[0] = y;
				this.yCoords[1] = y;
				this.yCoords[2] = y + height;
				this.yCoords[3] = y + height;
			}
			dg.fillPolygon( this.xCoords, 0, this.yCoords, 0, 4, this.argbColor );
		//#elifdef polish.midp2
			// on the SE K700 for example the translated origin of the graphics 
			// does not seem to used. Instead the real origin is used:
			//#ifdef polish.Bugs.drawRgbOrigin
				x += g.getTranslateX();
				y += g.getTranslateY();
			//#endif
				
			// check if the buffer needs to be created:
			
			//#if polish.Bugs.drawRgbNeedsFullBuffer
				if (width != this.lastWidth || height != this.lastHeight) {
					this.lastWidth = width;
					this.lastHeight = height;
					int[] newBuffer = new int[ width * height ];
					for (int i = newBuffer.length - 1; i >= 0 ; i--) {
						newBuffer[i] = this.argbColor;
					}
					this.buffer = newBuffer;
				}
			//#else
				if (width != this.lastWidth) {
					this.lastWidth = width;
					int[] newBuffer = new int[ width ];
					for (int i = newBuffer.length - 1; i >= 0 ; i--) {
						newBuffer[i] = this.argbColor;
					}
					this.buffer = newBuffer;
				}
			//#endif
			if (x < 0) {
				width += x;
				x = 0;
			}
			if (width <= 0) {
				return;
			}
			if (y < 0) {
				height += y;
				y = 0;
			}
			if (height <= 0) {
				return;
			}
			//#if polish.Bugs.drawRgbNeedsFullBuffer
				g.drawRGB(this.buffer, 0, width, x, y, width, height, true);
			//#else
				g.drawRGB(this.buffer, 0, 0, x, y, width, height, true);
			//#endif
//		//#elif polish.api.nokia-ui
//			if (width != this.lastWidth || height != this.lastHeight) {
//				this.lastWidth = width;
//				this.lastHeight = height;
//				this.imageBuffer = DirectUtils.createImage( width, height, this.argbColor );
//			}
//			//DirectGraphics dg = DirectUtils.getDirectGraphics(g);
//			dg.drawImage(this.imageBuffer, x, y, Graphics.TOP | Graphics.LEFT, 0 );
		//#else
			// ignore alpha-value
			g.setColor( this.argbColor );
			g.fillRect(x, y, width, height);
		//#endif
	}

	/**
	 * Releases all (memory intensive) resources such as images or RGB arrays of this background.
	 */
	public void releaseResources() {
		//#if !polish.api.nokia-ui && polish.midp2
			// int MIDP/2.0 the buffer is always used:
			this.buffer = null;
			this.lastWidth = 0;
		//#endif
	}
}