| /* AlphaCompositeContext.java -- CompositeContext impl for AlphaComposite |
| Copyright (C) 2006 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath 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, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.java.awt.java2d; |
| |
| import java.awt.AWTError; |
| import java.awt.AlphaComposite; |
| import java.awt.CompositeContext; |
| import java.awt.image.ColorModel; |
| import java.awt.image.Raster; |
| import java.awt.image.WritableRaster; |
| |
| /** |
| * A CompositeContext implementation for {@link AlphaComposite}. |
| * |
| * @author Roman Kennke (kennke@aicas.com) |
| */ |
| public class AlphaCompositeContext |
| implements CompositeContext |
| { |
| |
| /** |
| * The Composite object for which we perform compositing. |
| */ |
| private AlphaComposite composite; |
| |
| /** |
| * The source color model. |
| */ |
| private ColorModel srcColorModel; |
| |
| /** |
| * The destination color model. |
| */ |
| private ColorModel dstColorModel; |
| |
| /** |
| * The blending factor for the source. |
| */ |
| private float fs; |
| |
| /** |
| * The blending factor for the destination. |
| */ |
| private float fd; |
| |
| /** |
| * Creates a new AlphaCompositeContext. |
| * |
| * @param aComp the AlphaComposite object |
| * @param srcCM the source color model |
| * @param dstCM the destination color model |
| */ |
| public AlphaCompositeContext(AlphaComposite aComp, ColorModel srcCM, |
| ColorModel dstCM) |
| { |
| composite = aComp; |
| srcColorModel = srcCM; |
| dstColorModel = dstCM; |
| |
| |
| // Determine the blending factors according to the rule in the |
| // AlphaComposite. For some rules the factors must be determined |
| // dynamically because they depend on the actual pixel value. |
| switch (composite.getRule()) |
| { |
| case AlphaComposite.CLEAR: |
| fs = 0.F; |
| fd= 0.F; |
| break; |
| case AlphaComposite.DST: |
| fs = 0.F; |
| fd= 1.F; |
| break; |
| case AlphaComposite.DST_ATOP: |
| fs = 1.F; // Determined later as 1 - alpha_dst; |
| fd = 1.F; // Determined later as alpha_src; |
| break; |
| case AlphaComposite.DST_IN: |
| fs = 0.F; |
| fd = 0.F; // Determined later as alpha_src; |
| break; |
| case AlphaComposite.DST_OUT: |
| fs = 0.F; |
| fd = 0.F; // Determined later as 1 - alpha_src; |
| break; |
| case AlphaComposite.DST_OVER: |
| fs = 1.F; // Determined later as 1 - alpha_dst. |
| fd= 1.F; |
| break; |
| case AlphaComposite.SRC: |
| fs = 1.F; |
| fd= 0.F; |
| break; |
| case AlphaComposite.SRC_ATOP: |
| fs = 1.F; // Determined later as alpha_dst; |
| fd = 1.F; // Determined later as 1 - alpha_src; |
| break; |
| case AlphaComposite.SRC_IN: |
| fs = 0.F; // Determined later as alpha_dst; |
| fd = 0.F; |
| break; |
| case AlphaComposite.SRC_OUT: |
| fs = 0.F; // Determined later as 1 - alpha_dst; |
| fd = 0.F; |
| break; |
| case AlphaComposite.SRC_OVER: |
| fs = 1.F; |
| fd= 1.F; // Determined later as 1 - alpha_src. |
| break; |
| case AlphaComposite.XOR: |
| fs = 1.F; // Determined later as 1 - alpha_dst. |
| fd= 1.F; // Determined later as 1 - alpha_src. |
| break; |
| default: |
| throw new AWTError("Illegal AlphaComposite rule"); |
| } |
| |
| } |
| |
| /** |
| * Releases all resources held by this composite object. |
| */ |
| public void dispose() |
| { |
| // Nothing to do here yet. |
| } |
| |
| /** |
| * Performs compositing according to the rules specified in the |
| * AlphaComposite from the constructor. |
| */ |
| public void compose(Raster src, Raster dstIn, WritableRaster dstOut) |
| { |
| |
| // TODO: This implementation is very general and highly inefficient. There |
| // are two possible ways to optimize this: |
| // 1. Special cased implementations for common ColorModels and transfer |
| // types. |
| // 2. Native implementation. |
| |
| int x0 = src.getMinX(); |
| int y0 = src.getMinY(); |
| int width = src.getWidth(); |
| int height = src.getHeight(); |
| int x1 = x0 + width; |
| int y1 = y0 + height; |
| |
| Object srcPixel = null; |
| Object dstPixel = null; |
| |
| // Prepare the array that holds the color and alpha components of the |
| // source pixels. |
| float[] srcComponents; |
| int srcComponentsLength = srcColorModel.getNumComponents(); |
| if (! srcColorModel.hasAlpha()) |
| srcComponentsLength += 1; |
| srcComponents = new float[srcComponentsLength]; |
| |
| // Prepare the array that holds the color and alpha components of the |
| // destination pixels. |
| float[] dstComponents; |
| int dstComponentsLength = dstColorModel.getNumComponents(); |
| if (! dstColorModel.hasAlpha()) |
| dstComponentsLength += 1; |
| dstComponents = new float[dstComponentsLength]; |
| |
| if (srcComponentsLength != dstComponentsLength) |
| throw new AWTError("The color models of the source and destination have" |
| + "incompatible number of color components"); |
| |
| int srcTransferType = srcColorModel.getTransferType(); |
| int dstTransferType = dstColorModel.getTransferType(); |
| |
| for (int y = y0; y < y1; y++) |
| { |
| for (int x = x0; x < x1; x++) |
| { |
| // Fetch source pixel. |
| srcPixel = src.getDataElements(x, y, (int[]) srcPixel); |
| // Fetch destination pixel. |
| dstPixel = dstIn.getDataElements(x, y, dstPixel); |
| // Get normalized components. This is the only type that is |
| // guaranteed to be supported by all ColorModels. |
| srcComponents = |
| srcColorModel.getNormalizedComponents(srcPixel, srcComponents, 0); |
| if (! srcColorModel.hasAlpha()) |
| srcComponents[srcComponentsLength - 1] = 1.0F; |
| dstComponents = |
| dstColorModel.getNormalizedComponents(dstPixel, dstComponents, 0); |
| if (! dstColorModel.hasAlpha()) |
| dstComponents[dstComponentsLength - 1] = 1.0F; |
| |
| // Prepare the input. |
| float compositeAlpha = composite.getAlpha(); |
| srcComponents[srcComponentsLength - 1] *= compositeAlpha; |
| if (srcColorModel.isAlphaPremultiplied()) |
| { |
| for (int i = srcComponentsLength - 2; i >= 0; i--) |
| srcComponents[i] *= compositeAlpha; |
| } |
| else |
| { |
| for (int i = srcComponentsLength - 2; i >= 0; i--) |
| srcComponents[i] *= srcComponents[srcComponentsLength - 1]; |
| } |
| if (! dstColorModel.isAlphaPremultiplied()) |
| { |
| for (int i = dstComponentsLength - 2; i >= 0; i--) |
| dstComponents[i] *= dstComponents[dstComponents.length - 1]; |
| } |
| |
| // Determine the blending factors according to the rule in the |
| // AlphaComposite. For some rules the factors must be determined |
| // dynamically because they depend on the actual pixel value. |
| float srcAlpha = srcComponents[srcComponentsLength - 1]; |
| float dstAlpha = dstComponents[dstComponentsLength - 1]; |
| switch (composite.getRule()) |
| { |
| case AlphaComposite.DST_ATOP: |
| fs = 1.F - dstAlpha; |
| fd = srcAlpha; |
| break; |
| case AlphaComposite.DST_IN: |
| fd = srcAlpha; |
| break; |
| case AlphaComposite.DST_OUT: |
| fd = 1.F - srcAlpha; |
| break; |
| case AlphaComposite.DST_OVER: |
| fs = 1.F - dstAlpha; |
| break; |
| case AlphaComposite.SRC_ATOP: |
| fs = srcAlpha; |
| fd = 1.F - srcAlpha; |
| break; |
| case AlphaComposite.SRC_IN: |
| fs = dstAlpha; |
| break; |
| case AlphaComposite.SRC_OUT: |
| fs = 1.F - dstAlpha; |
| break; |
| case AlphaComposite.SRC_OVER: |
| fd= 1.F - srcAlpha; |
| break; |
| case AlphaComposite.XOR: |
| fs = 1.F - dstAlpha; |
| fd= 1.F - srcAlpha; |
| break; |
| default: |
| // For the other cases the factors have already been determined |
| // in the constructor. |
| } |
| |
| // Apply the blending equation to the pixels. |
| for (int i = 0; i < srcComponentsLength; i++) |
| { |
| dstComponents[i] = srcComponents[i] * fs |
| + dstComponents[i] * fd; |
| } |
| |
| // Convert the result back when the destination is not |
| // alpha-premultiplied. |
| dstAlpha = dstComponents[dstComponentsLength - 1]; |
| if (!dstColorModel.isAlphaPremultiplied() && dstAlpha != 0.F) |
| { |
| for (int i = 0; i < dstComponentsLength - 1; i++) |
| { |
| dstComponents[i] = dstComponents[i] / dstAlpha; |
| } |
| } |
| |
| // Store the result in the destination raster. |
| dstPixel = dstColorModel.getDataElements(dstComponents, 0, |
| dstPixel); |
| dstOut.setDataElements(x, y, dstPixel); |
| } // End X loop. |
| } // End Y loop. |
| } |
| |
| } |