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      1 /*
      2  * Copyright (C)2011, 2013-2015 D. R. Commander.  All Rights Reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are met:
      6  *
      7  * - Redistributions of source code must retain the above copyright notice,
      8  *   this list of conditions and the following disclaimer.
      9  * - Redistributions in binary form must reproduce the above copyright notice,
     10  *   this list of conditions and the following disclaimer in the documentation
     11  *   and/or other materials provided with the distribution.
     12  * - Neither the name of the libjpeg-turbo Project nor the names of its
     13  *   contributors may be used to endorse or promote products derived from this
     14  *   software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS",
     17  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
     20  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26  * POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 package org.libjpegturbo.turbojpeg;
     30 
     31 /**
     32  * TurboJPEG lossless transformer
     33  */
     34 public class TJTransformer extends TJDecompressor {
     35 
     36   /**
     37    * Create a TurboJPEG lossless transformer instance.
     38    */
     39   public TJTransformer() throws Exception {
     40     init();
     41   }
     42 
     43   /**
     44    * Create a TurboJPEG lossless transformer instance and associate the JPEG
     45    * image stored in <code>jpegImage</code> with the newly created instance.
     46    *
     47    * @param jpegImage JPEG image buffer (size of the JPEG image is assumed to
     48    * be the length of the array.)  This buffer is not modified.
     49    */
     50   public TJTransformer(byte[] jpegImage) throws Exception {
     51     init();
     52     setSourceImage(jpegImage, jpegImage.length);
     53   }
     54 
     55   /**
     56    * Create a TurboJPEG lossless transformer instance and associate the JPEG
     57    * image of length <code>imageSize</code> bytes stored in
     58    * <code>jpegImage</code> with the newly created instance.
     59    *
     60    * @param jpegImage JPEG image buffer.  This buffer is not modified.
     61    *
     62    * @param imageSize size of the JPEG image (in bytes)
     63    */
     64   public TJTransformer(byte[] jpegImage, int imageSize) throws Exception {
     65     init();
     66     setSourceImage(jpegImage, imageSize);
     67   }
     68 
     69   /**
     70    * Losslessly transform the JPEG image associated with this transformer
     71    * instance into one or more JPEG images stored in the given destination
     72    * buffers.  Lossless transforms work by moving the raw coefficients from one
     73    * JPEG image structure to another without altering the values of the
     74    * coefficients.  While this is typically faster than decompressing the
     75    * image, transforming it, and re-compressing it, lossless transforms are not
     76    * free.  Each lossless transform requires reading and performing Huffman
     77    * decoding on all of the coefficients in the source image, regardless of the
     78    * size of the destination image.  Thus, this method provides a means of
     79    * generating multiple transformed images from the same source or of applying
     80    * multiple transformations simultaneously, in order to eliminate the need to
     81    * read the source coefficients multiple times.
     82    *
     83    * @param dstBufs an array of image buffers.  <code>dstbufs[i]</code> will
     84    * receive a JPEG image that has been transformed using the parameters in
     85    * <code>transforms[i]</code>.  Use {@link TJ#bufSize} to determine the
     86    * maximum size for each buffer based on the transformed or cropped width and
     87    * height and the level of subsampling used in the source image.
     88    *
     89    * @param transforms an array of {@link TJTransform} instances, each of
     90    * which specifies the transform parameters and/or cropping region for the
     91    * corresponding transformed output image
     92    *
     93    * @param flags the bitwise OR of one or more of
     94    * {@link TJ#FLAG_BOTTOMUP TJ.FLAG_*}
     95    */
     96   public void transform(byte[][] dstBufs, TJTransform[] transforms,
     97                         int flags) throws Exception {
     98     if (jpegBuf == null)
     99       throw new Exception("JPEG buffer not initialized");
    100     transformedSizes = transform(jpegBuf, jpegBufSize, dstBufs, transforms,
    101                                  flags);
    102   }
    103 
    104   /**
    105    * Losslessly transform the JPEG image associated with this transformer
    106    * instance and return an array of {@link TJDecompressor} instances, each of
    107    * which has a transformed JPEG image associated with it.
    108    *
    109    * @param transforms an array of {@link TJTransform} instances, each of
    110    * which specifies the transform parameters and/or cropping region for the
    111    * corresponding transformed output image
    112    *
    113    * @return an array of {@link TJDecompressor} instances, each of
    114    * which has a transformed JPEG image associated with it.
    115    *
    116    * @param flags the bitwise OR of one or more of
    117    * {@link TJ#FLAG_BOTTOMUP TJ.FLAG_*}
    118    */
    119   public TJDecompressor[] transform(TJTransform[] transforms, int flags)
    120     throws Exception {
    121     byte[][] dstBufs = new byte[transforms.length][];
    122     if (jpegWidth < 1 || jpegHeight < 1)
    123       throw new Exception("JPEG buffer not initialized");
    124     for (int i = 0; i < transforms.length; i++) {
    125       int w = jpegWidth, h = jpegHeight;
    126       if ((transforms[i].options & TJTransform.OPT_CROP) != 0) {
    127         if (transforms[i].width != 0) w = transforms[i].width;
    128         if (transforms[i].height != 0) h = transforms[i].height;
    129       }
    130       dstBufs[i] = new byte[TJ.bufSize(w, h, jpegSubsamp)];
    131     }
    132     TJDecompressor[] tjd = new TJDecompressor[transforms.length];
    133     transform(dstBufs, transforms, flags);
    134     for (int i = 0; i < transforms.length; i++)
    135       tjd[i] = new TJDecompressor(dstBufs[i], transformedSizes[i]);
    136     return tjd;
    137   }
    138 
    139   /**
    140    * Returns an array containing the sizes of the transformed JPEG images
    141    * generated by the most recent transform operation.
    142    *
    143    * @return an array containing the sizes of the transformed JPEG images
    144    * generated by the most recent transform operation.
    145    */
    146   public int[] getTransformedSizes() throws Exception {
    147     if (transformedSizes == null)
    148       throw new Exception("No image has been transformed yet");
    149     return transformedSizes;
    150   }
    151 
    152   private native void init() throws Exception;
    153 
    154   private native int[] transform(byte[] srcBuf, int srcSize, byte[][] dstBufs,
    155     TJTransform[] transforms, int flags) throws Exception;
    156 
    157   static {
    158     TJLoader.load();
    159   }
    160 
    161   private int[] transformedSizes = null;
    162 };
    163