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jeremybenn |
/* AreaAveragingScaleFilter.java -- Java class for filtering images
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Copyright (C) 1999,2006 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.awt.image;
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/**
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* This filter should produce images which do not have image artifacts
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* like broken lines which were originally unbroken. The cost is of
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* course speed. Using bi-linear interpolation here against 4 pixel
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* points should give the desired results although Sun does not
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* specify what the exact algorithm should be.
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* <br>
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*
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* @author C. Brian Jones (cbj@gnu.org)
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*/
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public class AreaAveragingScaleFilter extends ReplicateScaleFilter
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{
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/**
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* Construct an instance of <code>AreaAveragingScaleFilter</code> which
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* should be used in conjunction with a <code>FilteredImageSource</code>
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* object.
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*
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* @param width the width of the destination image
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* @param height the height of the destination image
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*/
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public AreaAveragingScaleFilter(int width, int height) {
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super(width, height);
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}
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/**
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* The <code>ImageProducer</code> should call this method with a
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* bit mask of hints from any of <code>RANDOMPIXELORDER</code>,
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* <code>TOPDOWNLEFTRIGHT</code>, <code>COMPLETESCANLINES</code>,
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* <code>SINGLEPASS</code>, <code>SINGLEFRAME</code> from the
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* <code>ImageConsumer</code> interface.
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* <br>
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* FIXME - more than likely Sun's implementation desires
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* <code>TOPDOWNLEFTRIGHT</code> order and this method is overloaded here
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* in order to assure that mask is part of the hints added to
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* the consumer.
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*
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* @param flags a bit mask of hints
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* @see ImageConsumer
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*/
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public void setHints(int flags)
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{
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if (consumer != null)
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consumer.setHints(flags);
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}
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/**
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* This function delivers a rectangle of pixels where any
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* pixel(m,n) is stored in the array as a <code>byte</code> at
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* index (n * scansize + m + offset).
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*
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* @param x the x coordinate of the rectangle
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* @param y the y coordinate of the rectangle
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* @param w the width of the rectangle
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* @param h the height of the rectangle
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* @param model the <code>ColorModel</code> used to translate the pixels
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* @param pixels the array of pixel values
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* @param offset the index of the first pixels in the <code>pixels</code> array
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* @param scansize the width to use in extracting pixels from the <code>pixels</code> array
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*/
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public void setPixels(int x, int y, int w, int h,
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ColorModel model, byte[] pixels, int offset, int scansize)
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{
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double rx = ((double) srcWidth) / destWidth;
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double ry = ((double) srcHeight) / destHeight;
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int destScansize = (int) Math.round(scansize / rx);
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byte[] destPixels = averagePixels(x, y, w, h,
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model, pixels, offset, scansize,
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rx, ry, destScansize);
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if (consumer != null)
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consumer.setPixels((int) Math.floor(x/rx), (int) Math.floor(y/ry),
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(int) Math.ceil(w/rx), (int) Math.ceil(h/ry),
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model, destPixels, 0, destScansize);
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}
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/**
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* This function delivers a rectangle of pixels where any
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* pixel(m,n) is stored in the array as an <code>int</code> at
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* index (n * scansize + m + offset).
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*
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* @param x the x coordinate of the rectangle
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* @param y the y coordinate of the rectangle
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* @param w the width of the rectangle
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* @param h the height of the rectangle
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* @param model the <code>ColorModel</code> used to translate the pixels
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* @param pixels the array of pixel values
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* @param offset the index of the first pixels in the <code>pixels</code> array
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* @param scansize the width to use in extracting pixels from the <code>pixels</code> array
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*/
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public void setPixels(int x, int y, int w, int h,
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ColorModel model, int[] pixels, int offset, int scansize)
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{
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double rx = ((double) srcWidth) / destWidth;
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double ry = ((double) srcHeight) / destHeight;
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int destScansize = (int) Math.round(scansize / rx);
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int[] destPixels = averagePixels(x, y, w, h,
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model, pixels, offset, scansize,
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rx, ry, destScansize);
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if (consumer != null)
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consumer.setPixels((int) Math.floor(x/rx), (int) Math.floor(y/ry),
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(int) Math.ceil(w/rx), (int) Math.ceil(h/ry),
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model, destPixels, 0, destScansize);
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}
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/**
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* This is a really terrible implementation,
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* since it uses the nearest-neighbor method. This filter is rarely used though.
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*
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* @param srcx, srcy - Source rectangle upper-left corner
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* @param srcw, srch - Source rectangle width and height
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* @param model - Pixel color model
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* @param srcPixels - Source pixel data.
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* @param srcOffset - Starting offset into the source pixel data array.
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* @param srcScansize - Source array scanline size.
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* @param rx,ry - Scaling factor.
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* @param destScansize - Destination array scanline size.
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*/
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private byte[] averagePixels(int srcx, int srcy, int srcw, int srch,
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ColorModel model, byte[] srcPixels,
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int srcOffset, int srcScansize,
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double rx, double ry, int destScansize)
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{
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int destW = (int) Math.ceil(srcw/rx);
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int destH = (int) Math.ceil(srch/ry);
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byte[] destPixels = new byte[ destW * destH ];
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int sx, sy;
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int w = (int)Math.ceil(rx);
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int h = (int)Math.ceil(ry);
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for(int x = 0; x < destW; x++)
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for(int y = 0; y < destH; y++)
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{
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sx = (int) (x * rx);
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sy = (int) (y * ry);
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int r,g,b,a;
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r = g = b = a = 0;
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for(int i = 0; i < w; i++)
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{
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for(int j = 0; j < h; j++)
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{
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int idx = srcx + sx + i + (srcy + sy + j)*srcScansize;
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r += model.getRed(srcPixels[ idx ]);
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g += model.getGreen(srcPixels[ idx ]);
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b += model.getBlue(srcPixels[ idx ]);
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a += model.getAlpha(srcPixels[ idx ]);
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}
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}
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r = r / (w * h);
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g = g / (w * h);
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b = b / (w * h);
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a = a / (w * h);
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// Does this really work?
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destPixels[x + destScansize*y] = (byte)model.getDataElement
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(new int[]{r, g, b, a}, 0);
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}
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return destPixels;
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}
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/**
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* This is a really terrible implementation,
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* since it uses the nearest-neighbor method. This filter is rarely used though.
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*
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* @param srcx, srcy - Source rectangle upper-left corner
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* @param srcw, srch - Source rectangle width and height
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* @param model - Pixel color model
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* @param srcPixels - Source pixel data.
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* @param srcOffset - Starting offset into the source pixel data array.
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* @param srcScansize - Source array scanline size.
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* @param rx,ry - Scaling factor.
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* @param destScansize - Destination array scanline size.
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*/
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private int[] averagePixels(int srcx, int srcy, int srcw, int srch,
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ColorModel model, int[] srcPixels,
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int srcOffset, int srcScansize,
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double rx, double ry, int destScansize)
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{
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int destW = (int) Math.ceil(srcw/rx);
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int destH = (int) Math.ceil(srch/ry);
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int[] destPixels = new int[ destW * destH ];
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int sx, sy;
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int w = (int)Math.ceil(rx);
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int h = (int)Math.ceil(ry);
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for(int x = 0; x < destW; x++)
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for(int y = 0; y < destH; y++)
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{
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sx = (int) (x * rx);
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sy = (int) (y * ry);
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int r,g,b,a;
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r = g = b = a = 0;
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for(int i = 0; i < w; i++)
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{
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for(int j = 0; j < h; j++)
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{
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int idx = srcx + sx + i + (srcy + sy + j)*srcScansize;
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r += model.getRed(srcPixels[ idx ]);
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g += model.getGreen(srcPixels[ idx ]);
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b += model.getBlue(srcPixels[ idx ]);
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a += model.getAlpha(srcPixels[ idx ]);
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}
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}
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r = r / (w * h);
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g = g / (w * h);
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b = b / (w * h);
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a = a / (w * h);
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destPixels[x + destScansize*y] = model.getDataElement
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(new int[]{r, g, b, a}, 0);
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}
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return destPixels;
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}
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}
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