Java Tutorial/SWT 2D Graphics/Image

Rotate and flip an image

   <source lang="java">

/*******************************************************************************

* Copyright (c) 2000, 2004 IBM Corporation and others.
* 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
*
* Contributors:
*     IBM Corporation - initial API and implementation
*******************************************************************************/

//package org.eclipse.swt.snippets; /*

* This snippet was adapted from org.eclipse.draw2d.ImageUtilities in 
* http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.draw2d/?cvsroot=Tools_Project
* by Pratik Shah.
*
* example snippet: rotate and flip an image
*
* For a list of all SWT example snippets see
* http://www.eclipse.org/swt/snippets/
*/

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.Image; import org.eclipse.swt.graphics.ImageData; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell; public class ImageRotateFlip {

 static ImageData rotate(ImageData srcData, int direction) {
   int bytesPerPixel = srcData.bytesPerLine / srcData.width;
   int destBytesPerLine = (direction == SWT.DOWN) ? srcData.width * bytesPerPixel : srcData.height
       * bytesPerPixel;
   byte[] newData = new byte[(direction == SWT.DOWN) ? srcData.height * destBytesPerLine
       : srcData.width * destBytesPerLine];
   int width = 0, height = 0;
   for (int srcY = 0; srcY < srcData.height; srcY++) {
     for (int srcX = 0; srcX < srcData.width; srcX++) {
       int destX = 0, destY = 0, destIndex = 0, srcIndex = 0;
       switch (direction) {
       case SWT.LEFT: // left 90 degrees
         destX = srcY;
         destY = srcData.width - srcX - 1;
         width = srcData.height;
         height = srcData.width;
         break;
       case SWT.RIGHT: // right 90 degrees
         destX = srcData.height - srcY - 1;
         destY = srcX;
         width = srcData.height;
         height = srcData.width;
         break;
       case SWT.DOWN: // 180 degrees
         destX = srcData.width - srcX - 1;
         destY = srcData.height - srcY - 1;
         width = srcData.width;
         height = srcData.height;
         break;
       }
       destIndex = (destY * destBytesPerLine) + (destX * bytesPerPixel);
       srcIndex = (srcY * srcData.bytesPerLine) + (srcX * bytesPerPixel);
       System.arraycopy(srcData.data, srcIndex, newData, destIndex, bytesPerPixel);
     }
   }
   // destBytesPerLine is used as scanlinePad to ensure that no padding is
   // required
   return new ImageData(width, height, srcData.depth, srcData.palette, destBytesPerLine, newData);
 }
 static ImageData flip(ImageData srcData, boolean vertical) {
   int bytesPerPixel = srcData.bytesPerLine / srcData.width;
   int destBytesPerLine = srcData.width * bytesPerPixel;
   byte[] newData = new byte[srcData.data.length];
   for (int srcY = 0; srcY < srcData.height; srcY++) {
     for (int srcX = 0; srcX < srcData.width; srcX++) {
       int destX = 0, destY = 0, destIndex = 0, srcIndex = 0;
       if (vertical) {
         destX = srcX;
         destY = srcData.height - srcY - 1;
       } else {
         destX = srcData.width - srcX - 1;
         destY = srcY;
       }
       destIndex = (destY * destBytesPerLine) + (destX * bytesPerPixel);
       srcIndex = (srcY * srcData.bytesPerLine) + (srcX * bytesPerPixel);
       System.arraycopy(srcData.data, srcIndex, newData, destIndex, bytesPerPixel);
     }
   }
   // destBytesPerLine is used as scanlinePad to ensure that no padding is
   // required
   return new ImageData(srcData.width, srcData.height, srcData.depth, srcData.palette,
       destBytesPerLine, newData);
 }
 public static void main(String[] args) {
   Display display = new Display();
   // create an image with the word "hello" on it
   final Image image0 = new Image(display, 50, 30);
   GC gc = new GC(image0);
   gc.setBackground(display.getSystemColor(SWT.COLOR_RED));
   gc.fillRectangle(image0.getBounds());
   gc.drawString("hello", 5, 5, true);
   gc.dispose();
   ImageData data = image0.getImageData();
   // rotate and flip this image
   final Image image1 = new Image(display, rotate(data, SWT.LEFT));
   final Image image2 = new Image(display, rotate(data, SWT.RIGHT));
   final Image image3 = new Image(display, rotate(data, SWT.DOWN));
   final Image image4 = new Image(display, flip(data, true));
   final Image image5 = new Image(display, flip(data, false));
   Shell shell = new Shell(display);
   // draw the results on the shell
   shell.addPaintListener(new PaintListener() {
     public void paintControl(PaintEvent e) {
       e.gc.drawText("Original Image:", 10, 10, true);
       e.gc.drawImage(image0, 10, 40);
       e.gc.drawText("Left, Right, 180:", 10, 80, true);
       e.gc.drawImage(image1, 10, 110);
       e.gc.drawImage(image2, 50, 110);
       e.gc.drawImage(image3, 90, 110);
       e.gc.drawText("Flipped Vertical, Horizontal:", 10, 170, true);
       e.gc.drawImage(image4, 10, 200);
       e.gc.drawImage(image5, 70, 200);
     }
   });
   shell.setSize(300, 300);
   shell.open();
   while (!shell.isDisposed()) {
     if (!display.readAndDispatch())
       display.sleep();
   }
   image0.dispose();
   image1.dispose();
   image2.dispose();
   image3.dispose();
   image4.dispose();
   image5.dispose();
   display.dispose();
 }

}</source>