1 files changed, 168 insertions, 0 deletions
diff --git a/bundles/org.eclipse.compare/compare/org/eclipse/compare/internal/DiffImageDescriptor.java b/bundles/org.eclipse.compare/compare/org/eclipse/compare/internal/DiffImageDescriptor.java
new file mode 100644
index 000000000..a0ac41e04
--- /dev/null
+++ b/bundles/org.eclipse.compare/compare/org/eclipse/compare/internal/DiffImageDescriptor.java
@@ -0,0 +1,168 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2007 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.compare.internal;
+
+import org.eclipse.swt.graphics.*;
+
+import org.eclipse.jface.resource.CompositeImageDescriptor;
+import org.eclipse.jface.resource.ImageDescriptor;
+
+/**
+ * Combines an image with an overlay.
+ */
+public class DiffImageDescriptor extends CompositeImageDescriptor {
+
+	static final int HEIGHT= 16;
+
+	private final ImageData fBaseImageData;
+	private final ImageDescriptor fOverlayImage;
+	private final int fWidth;
+	private final boolean fLeft;
+	private final int hashCode;
+
+	public DiffImageDescriptor(Image base, ImageDescriptor overlay, int w, boolean onLeft) {
+		ImageData data = null;
+		if (base != null) {
+			data = base.getImageData();
+			if (data == null)
+				data = DEFAULT_IMAGE_DATA;
+		}
+		fBaseImageData = data;
+		fOverlayImage= overlay;
+		fWidth= w;
+		fLeft= onLeft;
+		hashCode = calculateHashCode();
+	}
+
+	private int calculateHashCode() {
+		int h1 = 0;
+		int h2 = 0;
+		if (fBaseImageData != null) {
+			h1 = calculateHash(fBaseImageData);
+		}
+		if (fOverlayImage != null) {
+			h2 = fOverlayImage.hashCode();
+		}
+		return h1 + h2 + fWidth;
+	}
+	
+	private int calculateHash(ImageData baseImageData) {
+		byte[] data = baseImageData.data;
+		int hash = baseImageData.width + baseImageData.height;
+		for (int i = 0; i < data.length; i++) {
+			byte b = data[i];
+			hash >>>= 1;
+			hash ^= b;
+		}
+		return hash;
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.jface.resource.CompositeImageDescriptor#getSize()
+	 */
+	protected Point getSize() {
+		return new Point(fWidth, HEIGHT);
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.jface.resource.CompositeImageDescriptor#drawCompositeImage(int, int)
+	 */
+	protected void drawCompositeImage(int width, int height) {
+		if (fLeft) {
+			if (fBaseImageData != null) {
+				drawImage(fBaseImageData, fWidth - fBaseImageData.width, 0);
+			}
+	
+			if (fOverlayImage != null) {
+				ImageData overlay= fOverlayImage.getImageData();
+				if (overlay == null)
+					overlay= DEFAULT_IMAGE_DATA;
+				drawImage(overlay, 0, (HEIGHT - overlay.height) / 2);
+			}
+		} else {
+			if (fBaseImageData != null) {
+				drawImage(fBaseImageData, 0, 0);
+			}
+	
+			if (fOverlayImage != null) {
+				ImageData overlay= fOverlayImage.getImageData();
+				if (overlay == null)
+					overlay= DEFAULT_IMAGE_DATA;
+				drawImage(overlay, fWidth - overlay.width, (HEIGHT - overlay.height) / 2);
+			}
+		}
+	}
+	
+	/* (non-Javadoc)
+	 * @see java.lang.Object#hashCode()
+	 */
+	public int hashCode() {
+		return hashCode;
+	}
+
+	/* (non-Javadoc)
+	 * @see java.lang.Object#equals(java.lang.Object)
+	 */
+	public boolean equals(Object obj) {
+		if (obj == this)
+			return true;
+		if (obj instanceof DiffImageDescriptor) {
+			DiffImageDescriptor other = (DiffImageDescriptor) obj;
+			return (other.hashCode == hashCode
+					&& isEqual(other.fOverlayImage, fOverlayImage)
+					&& other.fWidth == fWidth 
+					&& other.fLeft == fLeft
+					&& isEqual(other.fBaseImageData, fBaseImageData));
+		}
+		return false;
+	}
+	
+	private boolean isEqual(ImageData i1, ImageData i2) {
+		if (isEqual((Object) i1, (Object) i2)) {
+			return true;
+		}
+		if (i1 == null || i2 == null)
+			return false;
+		return (i1.width == i2.width && i1.height == i2.height
+				&& i1.depth == i2.depth && i1.scanlinePad == i2.scanlinePad
+				&& i1.bytesPerLine == i2.bytesPerLine
+				/* && i1.palette == i2.palette */
+				&& i1.transparentPixel == i2.transparentPixel
+				&& i1.maskPad == i2.maskPad
+	            && i1.alpha == i2.alpha
+				&& i1.type == i2.type && i1.x == i2.x && i1.y == i2.y
+				&& i1.disposalMethod == i2.disposalMethod && i1.delayTime == i2.delayTime
+				&& equals(i1.data,i2.data) && equals(i1.maskData, i2.maskData)
+				&& equals(i1.alphaData, i2.alphaData));
+	}
+	
+	private boolean equals(byte[] data, byte[] data2) {
+		if (isEqual(data, data2))
+			return true;
+		if (data == null || data2 == null)
+			return false;
+		if (data.length != data2.length)
+			return false;
+		for (int i = 0; i < data2.length; i++) {
+			if (data[i] != data2[i])
+				return false;
+		}
+		return true;
+	}
+
+	private boolean isEqual(Object o1, Object o2) {
+		if (o1 == o2)
+			return true;
+		if (o1 == null || o2 == null)
+			return false;
+		return o1.equals(o2);
+	}
+}