Support decoding subsets from JPG on Android.

src/images/SkImageDecoder_libjpeg.cpp

-
 /*
  * Copyright 2007 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkImageDecoder.h"
 #include "SkImageEncoder.h"
 #include "SkJpegUtility.h"
 #include "SkColorPriv.h"
 #include "SkDither.h"
 #include "SkScaledBitmapSampler.h"
 #include "SkStream.h"
 #include "SkTemplates.h"
 #include "SkTime.h"
 #include "SkUtils.h"
 #include "SkRect.h"
 #include "SkCanvas.h"
 
 #include <stdio.h>
 extern "C" {
     #include "jpeglib.h"
     #include "jerror.h"
 }
 
-// Uncomment to enable the code path used by the Android framework with their
-// custom image decoders.
-//#if defined(SK_BUILD_FOR_ANDROID) && defined(SK_DEBUG)
-//  #define SK_BUILD_FOR_ANDROID_FRAMEWORK
-//#endif
-
 // These enable timing code that report milliseconds for an encoding/decoding
 //#define TIME_ENCODE
 //#define TIME_DECODE
 
 // this enables our rgb->yuv code, which is faster than libjpeg on ARM
 // disable for the moment, as we have some glitches when width != multiple of 4
 #define WE_CONVERT_TO_YUV
 
 // If ANDROID_RGB is defined by in the jpeg headers it indicates that jpeg offers
 // support for two additional formats (1) JCS_RGBA_8888 and (2) JCS_RGB_565.
@@ skipping 16 matching lines @@
 
 //////////////////////////////////////////////////////////////////////////
 //////////////////////////////////////////////////////////////////////////
 
 class SkJPEGImageIndex {
 public:
     SkJPEGImageIndex(SkStream* stream, SkImageDecoder* decoder)
         : fSrcMgr(stream, decoder) {}
 
     ~SkJPEGImageIndex() {
-#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
+#ifdef SK_BUILD_FOR_ANDROID
         jpeg_destroy_huffman_index(&fHuffmanIndex);
 #endif
         jpeg_finish_decompress(&fCInfo);
         jpeg_destroy_decompress(&fCInfo);
     }
 
     /**
      * Init the cinfo struct using libjpeg and apply any necessary
      * customizations.
      */
     void initializeInfo() {
         jpeg_create_decompress(&fCInfo);
         overwrite_mem_buffer_size(&fCInfo);
         fCInfo.src = &fSrcMgr;
     }
 
     jpeg_decompress_struct* cinfo() { return &fCInfo; }
 
-#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
+#ifdef SK_BUILD_FOR_ANDROID
     huffman_index* huffmanIndex() { return &fHuffmanIndex; }
 #endif
 
 private:
     skjpeg_source_mgr  fSrcMgr;
     jpeg_decompress_struct fCInfo;
-#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
+#ifdef SK_BUILD_FOR_ANDROID
     huffman_index fHuffmanIndex;
 #endif
 };
 
 class SkJPEGImageDecoder : public SkImageDecoder {
 public:
     SkJPEGImageDecoder() {
         fImageIndex = NULL;
         fImageWidth = 0;
         fImageHeight = 0;
     }
 
     virtual ~SkJPEGImageDecoder() {
         SkDELETE(fImageIndex);
     }
 
     virtual Format getFormat() const {
         return kJPEG_Format;
     }
 
 protected:
-#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
+#ifdef SK_BUILD_FOR_ANDROID
     virtual bool onBuildTileIndex(SkStream *stream, int *width, int *height) SK_OVERRIDE;
     virtual bool onDecodeSubset(SkBitmap* bitmap, const SkIRect& rect) SK_OVERRIDE;
 #endif
     virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode) SK_OVERRIDE;
 
 private:
     SkJPEGImageIndex* fImageIndex;
     int fImageWidth;
     int fImageHeight;
 
@@ skipping 43 matching lines @@
     for (int i = 0; i < count; i++) {
         JSAMPLE* rowptr = (JSAMPLE*)buffer;
         int row_count = jpeg_read_scanlines(cinfo, &rowptr, 1);
         if (1 != row_count) {
             return false;
         }
     }
     return true;
 }
 
-#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
+#ifdef SK_BUILD_FOR_ANDROID
 static bool skip_src_rows_tile(jpeg_decompress_struct* cinfo,
                                huffman_index *index, void* buffer, int count) {
     for (int i = 0; i < count; i++) {
         JSAMPLE* rowptr = (JSAMPLE*)buffer;
         int row_count = jpeg_read_tile_scanline(cinfo, index, &rowptr);
         if (1 != row_count) {
             return false;
         }
     }
     return true;
@@ skipping 278 matching lines @@
     // we formally skip the rest, so we don't get a complaint from libjpeg
     if (!skip_src_rows(&cinfo, srcRow,
                        cinfo.output_height - cinfo.output_scanline)) {
         return return_false(cinfo, *bm, "skip rows");
     }
     jpeg_finish_decompress(&cinfo);
 
     return true;
 }
 
-#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
+#ifdef SK_BUILD_FOR_ANDROID
 bool SkJPEGImageDecoder::onBuildTileIndex(SkStream* stream, int *width, int *height) {
 
     SkJPEGImageIndex* imageIndex = SkNEW_ARGS(SkJPEGImageIndex, (stream, this));
     jpeg_decompress_struct* cinfo = imageIndex->cinfo();
     huffman_index* huffmanIndex = imageIndex->huffmanIndex();
 
     skjpeg_error_mgr sk_err;
     cinfo->err = jpeg_std_error(&sk_err);
     sk_err.error_exit = skjpeg_error_exit;
 
@@ skipping 529 matching lines @@
 }
 
 static SkImageEncoder* sk_libjpeg_efactory(SkImageEncoder::Type t) {
     return (SkImageEncoder::kJPEG_Type == t) ? SkNEW(SkJPEGImageEncoder) : NULL;
 }
 
 
 static SkTRegistry<SkImageDecoder*, SkStream*> gDReg(sk_libjpeg_dfactory);
 static SkTRegistry<SkImageDecoder::Format, SkStream*> gFormatReg(get_format_jpeg);
 static SkTRegistry<SkImageEncoder*, SkImageEncoder::Type> gEReg(sk_libjpeg_efactory);