| /* |
| * Copyright (c) 1996, 2002, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code 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 |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package java.awt.image; |
| |
| import java.awt.image.ImageConsumer; |
| import java.awt.image.ColorModel; |
| import java.util.Hashtable; |
| import java.awt.Rectangle; |
| |
| /** |
| * An ImageFilter class for scaling images using a simple area averaging |
| * algorithm that produces smoother results than the nearest neighbor |
| * algorithm. |
| * <p>This class extends the basic ImageFilter Class to scale an existing |
| * image and provide a source for a new image containing the resampled |
| * image. The pixels in the source image are blended to produce pixels |
| * for an image of the specified size. The blending process is analogous |
| * to scaling up the source image to a multiple of the destination size |
| * using pixel replication and then scaling it back down to the destination |
| * size by simply averaging all the pixels in the supersized image that |
| * fall within a given pixel of the destination image. If the data from |
| * the source is not delivered in TopDownLeftRight order then the filter |
| * will back off to a simple pixel replication behavior and utilize the |
| * requestTopDownLeftRightResend() method to refilter the pixels in a |
| * better way at the end. |
| * <p>It is meant to be used in conjunction with a FilteredImageSource |
| * object to produce scaled versions of existing images. Due to |
| * implementation dependencies, there may be differences in pixel values |
| * of an image filtered on different platforms. |
| * |
| * @see FilteredImageSource |
| * @see ReplicateScaleFilter |
| * @see ImageFilter |
| * |
| * @author Jim Graham |
| */ |
| public class AreaAveragingScaleFilter extends ReplicateScaleFilter { |
| private static final ColorModel rgbmodel = ColorModel.getRGBdefault(); |
| private static final int neededHints = (TOPDOWNLEFTRIGHT |
| | COMPLETESCANLINES); |
| |
| private boolean passthrough; |
| private float reds[], greens[], blues[], alphas[]; |
| private int savedy; |
| private int savedyrem; |
| |
| /** |
| * Constructs an AreaAveragingScaleFilter that scales the pixels from |
| * its source Image as specified by the width and height parameters. |
| * @param width the target width to scale the image |
| * @param height the target height to scale the image |
| */ |
| public AreaAveragingScaleFilter(int width, int height) { |
| super(width, height); |
| } |
| |
| /** |
| * Detect if the data is being delivered with the necessary hints |
| * to allow the averaging algorithm to do its work. |
| * <p> |
| * Note: This method is intended to be called by the |
| * {@code ImageProducer} of the {@code Image} whose |
| * pixels are being filtered. Developers using |
| * this class to filter pixels from an image should avoid calling |
| * this method directly since that operation could interfere |
| * with the filtering operation. |
| * @see ImageConsumer#setHints |
| */ |
| public void setHints(int hints) { |
| passthrough = ((hints & neededHints) != neededHints); |
| super.setHints(hints); |
| } |
| |
| private void makeAccumBuffers() { |
| reds = new float[destWidth]; |
| greens = new float[destWidth]; |
| blues = new float[destWidth]; |
| alphas = new float[destWidth]; |
| } |
| |
| private int[] calcRow() { |
| float origmult = ((float) srcWidth) * srcHeight; |
| if (outpixbuf == null || !(outpixbuf instanceof int[])) { |
| outpixbuf = new int[destWidth]; |
| } |
| int[] outpix = (int[]) outpixbuf; |
| for (int x = 0; x < destWidth; x++) { |
| float mult = origmult; |
| int a = Math.round(alphas[x] / mult); |
| if (a <= 0) { |
| a = 0; |
| } else if (a >= 255) { |
| a = 255; |
| } else { |
| // un-premultiply the components (by modifying mult here, we |
| // are effectively doing the divide by mult and divide by |
| // alpha in the same step) |
| mult = alphas[x] / 255; |
| } |
| int r = Math.round(reds[x] / mult); |
| int g = Math.round(greens[x] / mult); |
| int b = Math.round(blues[x] / mult); |
| if (r < 0) {r = 0;} else if (r > 255) {r = 255;} |
| if (g < 0) {g = 0;} else if (g > 255) {g = 255;} |
| if (b < 0) {b = 0;} else if (b > 255) {b = 255;} |
| outpix[x] = (a << 24 | r << 16 | g << 8 | b); |
| } |
| return outpix; |
| } |
| |
| private void accumPixels(int x, int y, int w, int h, |
| ColorModel model, Object pixels, int off, |
| int scansize) { |
| if (reds == null) { |
| makeAccumBuffers(); |
| } |
| int sy = y; |
| int syrem = destHeight; |
| int dy, dyrem; |
| if (sy == 0) { |
| dy = 0; |
| dyrem = 0; |
| } else { |
| dy = savedy; |
| dyrem = savedyrem; |
| } |
| while (sy < y + h) { |
| int amty; |
| if (dyrem == 0) { |
| for (int i = 0; i < destWidth; i++) { |
| alphas[i] = reds[i] = greens[i] = blues[i] = 0f; |
| } |
| dyrem = srcHeight; |
| } |
| if (syrem < dyrem) { |
| amty = syrem; |
| } else { |
| amty = dyrem; |
| } |
| int sx = 0; |
| int dx = 0; |
| int sxrem = 0; |
| int dxrem = srcWidth; |
| float a = 0f, r = 0f, g = 0f, b = 0f; |
| while (sx < w) { |
| if (sxrem == 0) { |
| sxrem = destWidth; |
| int rgb; |
| if (pixels instanceof byte[]) { |
| rgb = ((byte[]) pixels)[off + sx] & 0xff; |
| } else { |
| rgb = ((int[]) pixels)[off + sx]; |
| } |
| // getRGB() always returns non-premultiplied components |
| rgb = model.getRGB(rgb); |
| a = rgb >>> 24; |
| r = (rgb >> 16) & 0xff; |
| g = (rgb >> 8) & 0xff; |
| b = rgb & 0xff; |
| // premultiply the components if necessary |
| if (a != 255.0f) { |
| float ascale = a / 255.0f; |
| r *= ascale; |
| g *= ascale; |
| b *= ascale; |
| } |
| } |
| int amtx; |
| if (sxrem < dxrem) { |
| amtx = sxrem; |
| } else { |
| amtx = dxrem; |
| } |
| float mult = ((float) amtx) * amty; |
| alphas[dx] += mult * a; |
| reds[dx] += mult * r; |
| greens[dx] += mult * g; |
| blues[dx] += mult * b; |
| if ((sxrem -= amtx) == 0) { |
| sx++; |
| } |
| if ((dxrem -= amtx) == 0) { |
| dx++; |
| dxrem = srcWidth; |
| } |
| } |
| if ((dyrem -= amty) == 0) { |
| int outpix[] = calcRow(); |
| do { |
| consumer.setPixels(0, dy, destWidth, 1, |
| rgbmodel, outpix, 0, destWidth); |
| dy++; |
| } while ((syrem -= amty) >= amty && amty == srcHeight); |
| } else { |
| syrem -= amty; |
| } |
| if (syrem == 0) { |
| syrem = destHeight; |
| sy++; |
| off += scansize; |
| } |
| } |
| savedyrem = dyrem; |
| savedy = dy; |
| } |
| |
| /** |
| * Combine the components for the delivered byte pixels into the |
| * accumulation arrays and send on any averaged data for rows of |
| * pixels that are complete. If the correct hints were not |
| * specified in the setHints call then relay the work to our |
| * superclass which is capable of scaling pixels regardless of |
| * the delivery hints. |
| * <p> |
| * Note: This method is intended to be called by the |
| * {@code ImageProducer} of the {@code Image} |
| * whose pixels are being filtered. Developers using |
| * this class to filter pixels from an image should avoid calling |
| * this method directly since that operation could interfere |
| * with the filtering operation. |
| * @see ReplicateScaleFilter |
| */ |
| public void setPixels(int x, int y, int w, int h, |
| ColorModel model, byte pixels[], int off, |
| int scansize) { |
| if (passthrough) { |
| super.setPixels(x, y, w, h, model, pixels, off, scansize); |
| } else { |
| accumPixels(x, y, w, h, model, pixels, off, scansize); |
| } |
| } |
| |
| /** |
| * Combine the components for the delivered int pixels into the |
| * accumulation arrays and send on any averaged data for rows of |
| * pixels that are complete. If the correct hints were not |
| * specified in the setHints call then relay the work to our |
| * superclass which is capable of scaling pixels regardless of |
| * the delivery hints. |
| * <p> |
| * Note: This method is intended to be called by the |
| * {@code ImageProducer} of the {@code Image} |
| * whose pixels are being filtered. Developers using |
| * this class to filter pixels from an image should avoid calling |
| * this method directly since that operation could interfere |
| * with the filtering operation. |
| * @see ReplicateScaleFilter |
| */ |
| public void setPixels(int x, int y, int w, int h, |
| ColorModel model, int pixels[], int off, |
| int scansize) { |
| if (passthrough) { |
| super.setPixels(x, y, w, h, model, pixels, off, scansize); |
| } else { |
| accumPixels(x, y, w, h, model, pixels, off, scansize); |
| } |
| } |
| } |