001 /* ConvolveOp.java --
002 Copyright (C) 2004, 2005, 2006, Free Software Foundation -- ConvolveOp
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038
039 package java.awt.image;
040
041 import java.awt.RenderingHints;
042 import java.awt.geom.Point2D;
043 import java.awt.geom.Rectangle2D;
044
045 /**
046 * Convolution filter.
047 *
048 * ConvolveOp convolves the source image with a Kernel to generate a
049 * destination image. This involves multiplying each pixel and its neighbors
050 * with elements in the kernel to compute a new pixel.
051 *
052 * Each band in a Raster is convolved and copied to the destination Raster.
053 * For BufferedImages, convolution is applied to all components. Color
054 * conversion will be applied if needed.
055 *
056 * Note that this filter ignores whether the source or destination is alpha
057 * premultiplied. The reference spec states that data will be premultiplied
058 * prior to convolving and divided back out afterwards (if needed), but testing
059 * has shown that this is not the case with their implementation.
060 *
061 * @author jlquinn@optonline.net
062 */
063 public class ConvolveOp implements BufferedImageOp, RasterOp
064 {
065 /** Edge pixels are set to 0. */
066 public static final int EDGE_ZERO_FILL = 0;
067
068 /** Edge pixels are copied from the source. */
069 public static final int EDGE_NO_OP = 1;
070
071 private Kernel kernel;
072 private int edge;
073 private RenderingHints hints;
074
075 /**
076 * Construct a ConvolveOp.
077 *
078 * The edge condition specifies that pixels outside the area that can be
079 * filtered are either set to 0 or copied from the source image.
080 *
081 * @param kernel The kernel to convolve with.
082 * @param edgeCondition Either EDGE_ZERO_FILL or EDGE_NO_OP.
083 * @param hints Rendering hints for color conversion, or null.
084 */
085 public ConvolveOp(Kernel kernel,
086 int edgeCondition,
087 RenderingHints hints)
088 {
089 this.kernel = kernel;
090 edge = edgeCondition;
091 this.hints = hints;
092 }
093
094 /**
095 * Construct a ConvolveOp.
096 *
097 * The edge condition defaults to EDGE_ZERO_FILL.
098 *
099 * @param kernel The kernel to convolve with.
100 */
101 public ConvolveOp(Kernel kernel)
102 {
103 this.kernel = kernel;
104 edge = EDGE_ZERO_FILL;
105 hints = null;
106 }
107
108 /**
109 * Converts the source image using the kernel specified in the
110 * constructor. The resulting image is stored in the destination image if one
111 * is provided; otherwise a new BufferedImage is created and returned.
112 *
113 * The source and destination BufferedImage (if one is supplied) must have
114 * the same dimensions.
115 *
116 * @param src The source image.
117 * @param dst The destination image.
118 * @throws IllegalArgumentException if the rasters and/or color spaces are
119 * incompatible.
120 * @return The convolved image.
121 */
122 public final BufferedImage filter(BufferedImage src, BufferedImage dst)
123 {
124 if (src == dst)
125 throw new IllegalArgumentException("Source and destination images " +
126 "cannot be the same.");
127
128 if (dst == null)
129 dst = createCompatibleDestImage(src, src.getColorModel());
130
131 // Make sure source image is premultiplied
132 BufferedImage src1 = src;
133 // The spec says we should do this, but mauve testing shows that Sun's
134 // implementation does not check this.
135 /*
136 if (!src.isAlphaPremultiplied())
137 {
138 src1 = createCompatibleDestImage(src, src.getColorModel());
139 src.copyData(src1.getRaster());
140 src1.coerceData(true);
141 }
142 */
143
144 BufferedImage dst1 = dst;
145 if (src1.getColorModel().getColorSpace().getType() != dst.getColorModel().getColorSpace().getType())
146 dst1 = createCompatibleDestImage(src, src.getColorModel());
147
148 filter(src1.getRaster(), dst1.getRaster());
149
150 // Since we don't coerceData above, we don't need to divide it back out.
151 // This is wrong (one mauve test specifically tests converting a non-
152 // premultiplied image to a premultiplied image, and it shows that Sun
153 // simply ignores the premultipled flag, contrary to the spec), but we
154 // mimic it for compatibility.
155 /*
156 if (! dst.isAlphaPremultiplied())
157 dst1.coerceData(false);
158 */
159
160 // Convert between color models if needed
161 if (dst1 != dst)
162 new ColorConvertOp(hints).filter(dst1, dst);
163
164 return dst;
165 }
166
167 /**
168 * Creates an empty BufferedImage with the size equal to the source and the
169 * correct number of bands. The new image is created with the specified
170 * ColorModel, or if no ColorModel is supplied, an appropriate one is chosen.
171 *
172 * @param src The source image.
173 * @param dstCM A color model for the destination image (may be null).
174 * @return The new compatible destination image.
175 */
176 public BufferedImage createCompatibleDestImage(BufferedImage src,
177 ColorModel dstCM)
178 {
179 if (dstCM != null)
180 return new BufferedImage(dstCM,
181 src.getRaster().createCompatibleWritableRaster(),
182 src.isAlphaPremultiplied(), null);
183
184 return new BufferedImage(src.getWidth(), src.getHeight(), src.getType());
185 }
186
187 /* (non-Javadoc)
188 * @see java.awt.image.RasterOp#getRenderingHints()
189 */
190 public final RenderingHints getRenderingHints()
191 {
192 return hints;
193 }
194
195 /**
196 * Get the edge condition for this Op.
197 *
198 * @return The edge condition.
199 */
200 public int getEdgeCondition()
201 {
202 return edge;
203 }
204
205 /**
206 * Returns (a clone of) the convolution kernel.
207 *
208 * @return The convolution kernel.
209 */
210 public final Kernel getKernel()
211 {
212 return (Kernel) kernel.clone();
213 }
214
215 /**
216 * Converts the source raster using the kernel specified in the constructor.
217 * The resulting raster is stored in the destination raster if one is
218 * provided; otherwise a new WritableRaster is created and returned.
219 *
220 * If the convolved value for a sample is outside the range of [0-255], it
221 * will be clipped.
222 *
223 * The source and destination raster (if one is supplied) cannot be the same,
224 * and must also have the same dimensions.
225 *
226 * @param src The source raster.
227 * @param dest The destination raster.
228 * @throws IllegalArgumentException if the rasters identical.
229 * @throws ImagingOpException if the convolution is not possible.
230 * @return The transformed raster.
231 */
232 public final WritableRaster filter(Raster src, WritableRaster dest)
233 {
234 if (src == dest)
235 throw new IllegalArgumentException("src == dest is not allowed.");
236 if (kernel.getWidth() > src.getWidth()
237 || kernel.getHeight() > src.getHeight())
238 throw new ImagingOpException("The kernel is too large.");
239 if (dest == null)
240 dest = createCompatibleDestRaster(src);
241 else if (src.getNumBands() != dest.getNumBands())
242 throw new ImagingOpException("src and dest have different band counts.");
243
244 // calculate the borders that the op can't reach...
245 int kWidth = kernel.getWidth();
246 int kHeight = kernel.getHeight();
247 int left = kernel.getXOrigin();
248 int right = Math.max(kWidth - left - 1, 0);
249 int top = kernel.getYOrigin();
250 int bottom = Math.max(kHeight - top - 1, 0);
251
252 // Calculate max sample values for clipping
253 int[] maxValue = src.getSampleModel().getSampleSize();
254 for (int i = 0; i < maxValue.length; i++)
255 maxValue[i] = (int)Math.pow(2, maxValue[i]) - 1;
256
257 // process the region that is reachable...
258 int regionW = src.width - left - right;
259 int regionH = src.height - top - bottom;
260 float[] kvals = kernel.getKernelData(null);
261 float[] tmp = new float[kWidth * kHeight];
262
263 for (int x = 0; x < regionW; x++)
264 {
265 for (int y = 0; y < regionH; y++)
266 {
267 // FIXME: This needs a much more efficient implementation
268 for (int b = 0; b < src.getNumBands(); b++)
269 {
270 float v = 0;
271 src.getSamples(x, y, kWidth, kHeight, b, tmp);
272 for (int i = 0; i < tmp.length; i++)
273 v += tmp[tmp.length - i - 1] * kvals[i];
274 // FIXME: in the above line, I've had to reverse the order of
275 // the samples array to make the tests pass. I haven't worked
276 // out why this is necessary.
277
278 // This clipping is is undocumented, but determined by testing.
279 if (v > maxValue[b])
280 v = maxValue[b];
281 else if (v < 0)
282 v = 0;
283
284 dest.setSample(x + kernel.getXOrigin(), y + kernel.getYOrigin(),
285 b, v);
286 }
287 }
288 }
289
290 // fill in the top border
291 fillEdge(src, dest, 0, 0, src.width, top, edge);
292
293 // fill in the bottom border
294 fillEdge(src, dest, 0, src.height - bottom, src.width, bottom, edge);
295
296 // fill in the left border
297 fillEdge(src, dest, 0, top, left, regionH, edge);
298
299 // fill in the right border
300 fillEdge(src, dest, src.width - right, top, right, regionH, edge);
301
302 return dest;
303 }
304
305 /**
306 * Fills a range of pixels (typically at the edge of a raster) with either
307 * zero values (if <code>edgeOp</code> is <code>EDGE_ZERO_FILL</code>) or the
308 * corresponding pixel values from the source raster (if <code>edgeOp</code>
309 * is <code>EDGE_NO_OP</code>). This utility method is called by the
310 * {@link #fillEdge(Raster, WritableRaster, int, int, int, int, int)} method.
311 *
312 * @param src the source raster.
313 * @param dest the destination raster.
314 * @param x the x-coordinate of the top left pixel in the range.
315 * @param y the y-coordinate of the top left pixel in the range.
316 * @param w the width of the pixel range.
317 * @param h the height of the pixel range.
318 * @param edgeOp indicates how to determine the values for the range
319 * (either {@link #EDGE_ZERO_FILL} or {@link #EDGE_NO_OP}).
320 */
321 private void fillEdge(Raster src, WritableRaster dest, int x, int y, int w,
322 int h, int edgeOp)
323 {
324 if (w <= 0)
325 return;
326 if (h <= 0)
327 return;
328 if (edgeOp == EDGE_ZERO_FILL) // fill region with zeroes
329 {
330 float[] zeros = new float[src.getNumBands() * w * h];
331 dest.setPixels(x, y, w, h, zeros);
332 }
333 else // copy pixels from source
334 {
335 float[] pixels = new float[src.getNumBands() * w * h];
336 src.getPixels(x, y, w, h, pixels);
337 dest.setPixels(x, y, w, h, pixels);
338 }
339 }
340
341 /* (non-Javadoc)
342 * @see java.awt.image.RasterOp#createCompatibleDestRaster(java.awt.image.Raster)
343 */
344 public WritableRaster createCompatibleDestRaster(Raster src)
345 {
346 return src.createCompatibleWritableRaster();
347 }
348
349 /* (non-Javadoc)
350 * @see java.awt.image.BufferedImageOp#getBounds2D(java.awt.image.BufferedImage)
351 */
352 public final Rectangle2D getBounds2D(BufferedImage src)
353 {
354 return src.getRaster().getBounds();
355 }
356
357 /* (non-Javadoc)
358 * @see java.awt.image.RasterOp#getBounds2D(java.awt.image.Raster)
359 */
360 public final Rectangle2D getBounds2D(Raster src)
361 {
362 return src.getBounds();
363 }
364
365 /**
366 * Returns the corresponding destination point for a source point. Because
367 * this is not a geometric operation, the destination and source points will
368 * be identical.
369 *
370 * @param src The source point.
371 * @param dst The transformed destination point.
372 * @return The transformed destination point.
373 */
374 public final Point2D getPoint2D(Point2D src, Point2D dst)
375 {
376 if (dst == null) return (Point2D)src.clone();
377 dst.setLocation(src);
378 return dst;
379 }
380 }