Restore SkImageDecoder_libjpeg, which may still be used by the Android build.

git-svn-id: http://skia.googlecode.com/svn/trunk@3304 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 642 insertions, 0 deletions

diff --git a/src/images/SkImageDecoder_libjpeg.cpp b/src/images/SkImageDecoder_libjpeg.cpp
new file mode 100644
index 0000000000..77d383af97
--- /dev/null
+++ b/src/images/SkImageDecoder_libjpeg.cpp
@@ -0,0 +1,642 @@
+
+/*
+ * 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 "SkUtils.h"
+
+#include <stdio.h>
+extern "C" {
+    #include "jpeglib.h"
+    #include "jerror.h"
+}
+
+#ifdef SK_BUILD_FOR_ANDROID
+#include <cutils/properties.h>
+
+// Key to lookup the size of memory buffer set in system property
+static const char KEY_MEM_CAP[] = "ro.media.dec.jpeg.memcap";
+#endif
+
+// this enables timing code to report milliseconds for an encode
+//#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
+
+//////////////////////////////////////////////////////////////////////////
+//////////////////////////////////////////////////////////////////////////
+
+class SkJPEGImageDecoder : public SkImageDecoder {
+public:
+    virtual Format getFormat() const {
+        return kJPEG_Format;
+    }
+
+protected:
+    virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode);
+};
+
+//////////////////////////////////////////////////////////////////////////
+
+#include "SkTime.h"
+
+class AutoTimeMillis {
+public:
+    AutoTimeMillis(const char label[]) : fLabel(label) {
+        if (!fLabel) {
+            fLabel = "";
+        }
+        fNow = SkTime::GetMSecs();
+    }
+    ~AutoTimeMillis() {
+        SkDebugf("---- Time (ms): %s %d\n", fLabel, SkTime::GetMSecs() - fNow);
+    }
+private:
+    const char* fLabel;
+    SkMSec      fNow;
+};
+
+/* Automatically clean up after throwing an exception */
+class JPEGAutoClean {
+public:
+    JPEGAutoClean(): cinfo_ptr(NULL) {}
+    ~JPEGAutoClean() {
+        if (cinfo_ptr) {
+            jpeg_destroy_decompress(cinfo_ptr);
+        }
+    }
+    void set(jpeg_decompress_struct* info) {
+        cinfo_ptr = info;
+    }
+private:
+    jpeg_decompress_struct* cinfo_ptr;
+};
+
+#ifdef SK_BUILD_FOR_ANDROID
+/* Check if the memory cap property is set.
+   If so, use the memory size for jpeg decode.
+*/
+static void overwrite_mem_buffer_size(j_decompress_ptr cinfo) {
+#ifdef ANDROID_LARGE_MEMORY_DEVICE
+    cinfo->mem->max_memory_to_use = 30 * 1024 * 1024;
+#else
+    cinfo->mem->max_memory_to_use = 5 * 1024 * 1024;
+#endif
+}
+#endif
+
+
+///////////////////////////////////////////////////////////////////////////////
+
+/*  If we need to better match the request, we might examine the image and
+     output dimensions, and determine if the downsampling jpeg provided is
+     not sufficient. If so, we can recompute a modified sampleSize value to
+     make up the difference.
+
+     To skip this additional scaling, just set sampleSize = 1; below.
+ */
+static int recompute_sampleSize(int sampleSize,
+                                const jpeg_decompress_struct& cinfo) {
+    return sampleSize * cinfo.output_width / cinfo.image_width;
+}
+
+static bool valid_output_dimensions(const jpeg_decompress_struct& cinfo) {
+    /* These are initialized to 0, so if they have non-zero values, we assume
+       they are "valid" (i.e. have been computed by libjpeg)
+     */
+    return cinfo.output_width != 0 && cinfo.output_height != 0;
+}
+
+static bool skip_src_rows(jpeg_decompress_struct* cinfo, void* buffer,
+                          int count) {
+    for (int i = 0; i < count; i++) {
+        JSAMPLE* rowptr = (JSAMPLE*)buffer;
+        int row_count = jpeg_read_scanlines(cinfo, &rowptr, 1);
+        if (row_count != 1) {
+            return false;
+        }
+    }
+    return true;
+}
+
+// This guy exists just to aid in debugging, as it allows debuggers to just
+// set a break-point in one place to see all error exists.
+static bool return_false(const jpeg_decompress_struct& cinfo,
+                         const SkBitmap& bm, const char msg[]) {
+#if 0
+    SkDebugf("libjpeg error %d <%s> from %s [%d %d]", cinfo.err->msg_code,
+             cinfo.err->jpeg_message_table[cinfo.err->msg_code], msg,
+             bm.width(), bm.height());
+#endif
+    return false;   // must always return false
+}
+
+bool SkJPEGImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
+#ifdef TIME_DECODE
+    AutoTimeMillis atm("JPEG Decode");
+#endif
+
+    SkAutoMalloc  srcStorage;
+    JPEGAutoClean autoClean;
+
+    jpeg_decompress_struct  cinfo;
+    skjpeg_error_mgr        sk_err;
+    skjpeg_source_mgr       sk_stream(stream, this);
+
+    cinfo.err = jpeg_std_error(&sk_err);
+    sk_err.error_exit = skjpeg_error_exit;
+
+    // All objects need to be instantiated before this setjmp call so that
+    // they will be cleaned up properly if an error occurs.
+    if (setjmp(sk_err.fJmpBuf)) {
+        return return_false(cinfo, *bm, "setjmp");
+    }
+
+    jpeg_create_decompress(&cinfo);
+    autoClean.set(&cinfo);
+
+#ifdef SK_BUILD_FOR_ANDROID
+    overwrite_mem_buffer_size(&cinfo);
+#endif
+
+    //jpeg_stdio_src(&cinfo, file);
+    cinfo.src = &sk_stream;
+
+    int status = jpeg_read_header(&cinfo, true);
+    if (status != JPEG_HEADER_OK) {
+        return return_false(cinfo, *bm, "read_header");
+    }
+
+    /*  Try to fulfill the requested sampleSize. Since jpeg can do it (when it
+        can) much faster that we, just use their num/denom api to approximate
+        the size.
+    */
+    int sampleSize = this->getSampleSize();
+
+    cinfo.dct_method = JDCT_IFAST;
+    cinfo.scale_num = 1;
+    cinfo.scale_denom = sampleSize;
+
+    /* this gives about 30% performance improvement. In theory it may
+       reduce the visual quality, in practice I'm not seeing a difference
+     */
+    cinfo.do_fancy_upsampling = 0;
+
+    /* this gives another few percents */
+    cinfo.do_block_smoothing = 0;
+
+    /* default format is RGB */
+    cinfo.out_color_space = JCS_RGB;
+
+    SkBitmap::Config config = this->getPrefConfig(k32Bit_SrcDepth, false);
+    // only these make sense for jpegs
+    if (config != SkBitmap::kARGB_8888_Config &&
+        config != SkBitmap::kARGB_4444_Config &&
+        config != SkBitmap::kRGB_565_Config) {
+        config = SkBitmap::kARGB_8888_Config;
+    }
+
+#ifdef ANDROID_RGB
+    cinfo.dither_mode = JDITHER_NONE;
+    if (config == SkBitmap::kARGB_8888_Config) {
+        cinfo.out_color_space = JCS_RGBA_8888;
+    } else if (config == SkBitmap::kRGB_565_Config) {
+        cinfo.out_color_space = JCS_RGB_565;
+        if (this->getDitherImage()) {
+            cinfo.dither_mode = JDITHER_ORDERED;
+        }
+    }
+#endif
+
+    if (sampleSize == 1 && mode == SkImageDecoder::kDecodeBounds_Mode) {
+        bm->setConfig(config, cinfo.image_width, cinfo.image_height);
+        bm->setIsOpaque(true);
+        return true;
+    }
+
+    /*  image_width and image_height are the original dimensions, available
+        after jpeg_read_header(). To see the scaled dimensions, we have to call
+        jpeg_start_decompress(), and then read output_width and output_height.
+    */
+    if (!jpeg_start_decompress(&cinfo)) {
+        /*  If we failed here, we may still have enough information to return
+            to the caller if they just wanted (subsampled bounds). If sampleSize
+            was 1, then we would have already returned. Thus we just check if
+            we're in kDecodeBounds_Mode, and that we have valid output sizes.
+
+            One reason to fail here is that we have insufficient stream data
+            to complete the setup. However, output dimensions seem to get
+            computed very early, which is why this special check can pay off.
+         */
+        if (SkImageDecoder::kDecodeBounds_Mode == mode &&
+                valid_output_dimensions(cinfo)) {
+            SkScaledBitmapSampler smpl(cinfo.output_width, cinfo.output_height,
+                                       recompute_sampleSize(sampleSize, cinfo));
+            bm->setConfig(config, smpl.scaledWidth(), smpl.scaledHeight());
+            bm->setIsOpaque(true);
+            return true;
+        } else {
+            return return_false(cinfo, *bm, "start_decompress");
+        }
+    }
+    sampleSize = recompute_sampleSize(sampleSize, cinfo);
+
+    // should we allow the Chooser (if present) to pick a config for us???
+    if (!this->chooseFromOneChoice(config, cinfo.output_width,
+                                   cinfo.output_height)) {
+        return return_false(cinfo, *bm, "chooseFromOneChoice");
+    }
+
+#ifdef ANDROID_RGB
+    /* short-circuit the SkScaledBitmapSampler when possible, as this gives
+       a significant performance boost.
+    */
+    if (sampleSize == 1 &&
+        ((config == SkBitmap::kARGB_8888_Config && 
+                cinfo.out_color_space == JCS_RGBA_8888) ||
+        (config == SkBitmap::kRGB_565_Config && 
+                cinfo.out_color_space == JCS_RGB_565)))
+    {
+        bm->setConfig(config, cinfo.output_width, cinfo.output_height);
+        bm->setIsOpaque(true);
+        if (SkImageDecoder::kDecodeBounds_Mode == mode) {
+            return true;
+        }
+        if (!this->allocPixelRef(bm, NULL)) {
+            return return_false(cinfo, *bm, "allocPixelRef");
+        }
+        SkAutoLockPixels alp(*bm);
+        JSAMPLE* rowptr = (JSAMPLE*)bm->getPixels();
+        INT32 const bpr =  bm->rowBytes();
+        
+        while (cinfo.output_scanline < cinfo.output_height) {
+            int row_count = jpeg_read_scanlines(&cinfo, &rowptr, 1);
+            // if row_count == 0, then we didn't get a scanline, so abort.
+            // if we supported partial images, we might return true in this case
+            if (0 == row_count) {
+                return return_false(cinfo, *bm, "read_scanlines");
+            }
+            if (this->shouldCancelDecode()) {
+                return return_false(cinfo, *bm, "shouldCancelDecode");
+            }
+            rowptr += bpr;
+        }
+        jpeg_finish_decompress(&cinfo);
+        return true;
+    }
+#endif
+    
+    // check for supported formats
+    SkScaledBitmapSampler::SrcConfig sc;
+    if (3 == cinfo.out_color_components && JCS_RGB == cinfo.out_color_space) {
+        sc = SkScaledBitmapSampler::kRGB;
+#ifdef ANDROID_RGB
+    } else if (JCS_RGBA_8888 == cinfo.out_color_space) {
+        sc = SkScaledBitmapSampler::kRGBX;
+    } else if (JCS_RGB_565 == cinfo.out_color_space) {
+        sc = SkScaledBitmapSampler::kRGB_565;
+#endif
+    } else if (1 == cinfo.out_color_components &&
+               JCS_GRAYSCALE == cinfo.out_color_space) {
+        sc = SkScaledBitmapSampler::kGray;
+    } else {
+        return return_false(cinfo, *bm, "jpeg colorspace");
+    }
+
+    SkScaledBitmapSampler sampler(cinfo.output_width, cinfo.output_height,
+                                  sampleSize);
+
+    bm->setConfig(config, sampler.scaledWidth(), sampler.scaledHeight());
+    // jpegs are always opauqe (i.e. have no per-pixel alpha)
+    bm->setIsOpaque(true);
+
+    if (SkImageDecoder::kDecodeBounds_Mode == mode) {
+        return true;
+    }
+    if (!this->allocPixelRef(bm, NULL)) {
+        return return_false(cinfo, *bm, "allocPixelRef");
+    }
+
+    SkAutoLockPixels alp(*bm);                          
+    if (!sampler.begin(bm, sc, this->getDitherImage())) {
+        return return_false(cinfo, *bm, "sampler.begin");
+    }
+
+    uint8_t* srcRow = (uint8_t*)srcStorage.alloc(cinfo.output_width * 4);
+
+    //  Possibly skip initial rows [sampler.srcY0]
+    if (!skip_src_rows(&cinfo, srcRow, sampler.srcY0())) {
+        return return_false(cinfo, *bm, "skip rows");
+    }
+
+    // now loop through scanlines until y == bm->height() - 1
+    for (int y = 0;; y++) {
+        JSAMPLE* rowptr = (JSAMPLE*)srcRow;
+        int row_count = jpeg_read_scanlines(&cinfo, &rowptr, 1);
+        if (0 == row_count) {
+            return return_false(cinfo, *bm, "read_scanlines");
+        }
+        if (this->shouldCancelDecode()) {
+            return return_false(cinfo, *bm, "shouldCancelDecode");
+        }
+        
+        sampler.next(srcRow);
+        if (bm->height() - 1 == y) {
+            // we're done
+            break;
+        }
+
+        if (!skip_src_rows(&cinfo, srcRow, sampler.srcDY() - 1)) {
+            return return_false(cinfo, *bm, "skip rows");
+        }
+    }
+
+    // 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);
+
+//    SkDebugf("------------------- bm2 size %d [%d %d] %d\n", bm->getSize(), bm->width(), bm->height(), bm->config());
+    return true;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+#include "SkColorPriv.h"
+
+// taken from jcolor.c in libjpeg
+#if 0   // 16bit - precise but slow
+    #define CYR     19595   // 0.299
+    #define CYG     38470   // 0.587
+    #define CYB      7471   // 0.114
+
+    #define CUR    -11059   // -0.16874
+    #define CUG    -21709   // -0.33126
+    #define CUB     32768   // 0.5
+
+    #define CVR     32768   // 0.5
+    #define CVG    -27439   // -0.41869
+    #define CVB     -5329   // -0.08131
+
+    #define CSHIFT  16
+#else      // 8bit - fast, slightly less precise
+    #define CYR     77    // 0.299
+    #define CYG     150    // 0.587
+    #define CYB      29    // 0.114
+
+    #define CUR     -43    // -0.16874
+    #define CUG    -85    // -0.33126
+    #define CUB     128    // 0.5
+
+    #define CVR      128   // 0.5
+    #define CVG     -107   // -0.41869
+    #define CVB      -21   // -0.08131
+
+    #define CSHIFT  8
+#endif
+
+static void rgb2yuv_32(uint8_t dst[], SkPMColor c) {
+    int r = SkGetPackedR32(c);
+    int g = SkGetPackedG32(c);
+    int b = SkGetPackedB32(c);
+
+    int  y = ( CYR*r + CYG*g + CYB*b ) >> CSHIFT;
+    int  u = ( CUR*r + CUG*g + CUB*b ) >> CSHIFT;
+    int  v = ( CVR*r + CVG*g + CVB*b ) >> CSHIFT;
+
+    dst[0] = SkToU8(y);
+    dst[1] = SkToU8(u + 128);
+    dst[2] = SkToU8(v + 128);
+}
+
+static void rgb2yuv_4444(uint8_t dst[], U16CPU c) {
+    int r = SkGetPackedR4444(c);
+    int g = SkGetPackedG4444(c);
+    int b = SkGetPackedB4444(c);
+
+    int  y = ( CYR*r + CYG*g + CYB*b ) >> (CSHIFT - 4);
+    int  u = ( CUR*r + CUG*g + CUB*b ) >> (CSHIFT - 4);
+    int  v = ( CVR*r + CVG*g + CVB*b ) >> (CSHIFT - 4);
+
+    dst[0] = SkToU8(y);
+    dst[1] = SkToU8(u + 128);
+    dst[2] = SkToU8(v + 128);
+}
+
+static void rgb2yuv_16(uint8_t dst[], U16CPU c) {
+    int r = SkGetPackedR16(c);
+    int g = SkGetPackedG16(c);
+    int b = SkGetPackedB16(c);
+
+    int  y = ( 2*CYR*r + CYG*g + 2*CYB*b ) >> (CSHIFT - 2);
+    int  u = ( 2*CUR*r + CUG*g + 2*CUB*b ) >> (CSHIFT - 2);
+    int  v = ( 2*CVR*r + CVG*g + 2*CVB*b ) >> (CSHIFT - 2);
+
+    dst[0] = SkToU8(y);
+    dst[1] = SkToU8(u + 128);
+    dst[2] = SkToU8(v + 128);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+typedef void (*WriteScanline)(uint8_t* SK_RESTRICT dst,
+                              const void* SK_RESTRICT src, int width,
+                              const SkPMColor* SK_RESTRICT ctable);
+
+static void Write_32_YUV(uint8_t* SK_RESTRICT dst,
+                         const void* SK_RESTRICT srcRow, int width,
+                         const SkPMColor*) {
+    const uint32_t* SK_RESTRICT src = (const uint32_t*)srcRow;
+    while (--width >= 0) {
+#ifdef WE_CONVERT_TO_YUV
+        rgb2yuv_32(dst, *src++);
+#else
+        uint32_t c = *src++;
+        dst[0] = SkGetPackedR32(c);
+        dst[1] = SkGetPackedG32(c);
+        dst[2] = SkGetPackedB32(c);
+#endif
+        dst += 3;
+    }
+}
+
+static void Write_4444_YUV(uint8_t* SK_RESTRICT dst,
+                           const void* SK_RESTRICT srcRow, int width,
+                           const SkPMColor*) {
+    const SkPMColor16* SK_RESTRICT src = (const SkPMColor16*)srcRow;
+    while (--width >= 0) {
+#ifdef WE_CONVERT_TO_YUV
+        rgb2yuv_4444(dst, *src++);
+#else
+        SkPMColor16 c = *src++;
+        dst[0] = SkPacked4444ToR32(c);
+        dst[1] = SkPacked4444ToG32(c);
+        dst[2] = SkPacked4444ToB32(c);
+#endif
+        dst += 3;
+    }
+}
+
+static void Write_16_YUV(uint8_t* SK_RESTRICT dst,
+                         const void* SK_RESTRICT srcRow, int width,
+                         const SkPMColor*) {
+    const uint16_t* SK_RESTRICT src = (const uint16_t*)srcRow;
+    while (--width >= 0) {
+#ifdef WE_CONVERT_TO_YUV
+        rgb2yuv_16(dst, *src++);
+#else
+        uint16_t c = *src++;
+        dst[0] = SkPacked16ToR32(c);
+        dst[1] = SkPacked16ToG32(c);
+        dst[2] = SkPacked16ToB32(c);
+#endif
+        dst += 3;
+    }
+}
+
+static void Write_Index_YUV(uint8_t* SK_RESTRICT dst,
+                            const void* SK_RESTRICT srcRow, int width,
+                            const SkPMColor* SK_RESTRICT ctable) {
+    const uint8_t* SK_RESTRICT src = (const uint8_t*)srcRow;
+    while (--width >= 0) {
+#ifdef WE_CONVERT_TO_YUV
+        rgb2yuv_32(dst, ctable[*src++]);
+#else
+        uint32_t c = ctable[*src++];
+        dst[0] = SkGetPackedR32(c);
+        dst[1] = SkGetPackedG32(c);
+        dst[2] = SkGetPackedB32(c);
+#endif
+        dst += 3;
+    }
+}
+
+static WriteScanline ChooseWriter(const SkBitmap& bm) {
+    switch (bm.config()) {
+        case SkBitmap::kARGB_8888_Config:
+            return Write_32_YUV;
+        case SkBitmap::kRGB_565_Config:
+            return Write_16_YUV;
+        case SkBitmap::kARGB_4444_Config:
+            return Write_4444_YUV;
+        case SkBitmap::kIndex8_Config:
+            return Write_Index_YUV;
+        default:
+            return NULL;
+    }
+}
+
+class SkJPEGImageEncoder : public SkImageEncoder {
+protected:
+    virtual bool onEncode(SkWStream* stream, const SkBitmap& bm, int quality) {
+#ifdef TIME_ENCODE
+        AutoTimeMillis atm("JPEG Encode");
+#endif
+
+        const WriteScanline writer = ChooseWriter(bm);
+        if (NULL == writer) {
+            return false;
+        }
+
+        SkAutoLockPixels alp(bm);
+        if (NULL == bm.getPixels()) {
+            return false;
+        }
+
+        jpeg_compress_struct    cinfo;
+        skjpeg_error_mgr        sk_err;
+        skjpeg_destination_mgr  sk_wstream(stream);
+
+        // allocate these before set call setjmp
+        SkAutoMalloc    oneRow;
+        SkAutoLockColors ctLocker;
+
+        cinfo.err = jpeg_std_error(&sk_err);
+        sk_err.error_exit = skjpeg_error_exit;
+        if (setjmp(sk_err.fJmpBuf)) {
+            return false;
+        }
+        jpeg_create_compress(&cinfo);
+
+        cinfo.dest = &sk_wstream;
+        cinfo.image_width = bm.width();
+        cinfo.image_height = bm.height();
+        cinfo.input_components = 3;
+#ifdef WE_CONVERT_TO_YUV
+        cinfo.in_color_space = JCS_YCbCr;
+#else
+        cinfo.in_color_space = JCS_RGB;
+#endif
+        cinfo.input_gamma = 1;
+
+        jpeg_set_defaults(&cinfo);
+        jpeg_set_quality(&cinfo, quality, TRUE /* limit to baseline-JPEG values */);
+        cinfo.dct_method = JDCT_IFAST;
+
+        jpeg_start_compress(&cinfo, TRUE);
+
+        const int       width = bm.width();
+        uint8_t*        oneRowP = (uint8_t*)oneRow.alloc(width * 3);
+
+        const SkPMColor* colors = ctLocker.lockColors(bm);
+        const void*      srcRow = bm.getPixels();
+
+        while (cinfo.next_scanline < cinfo.image_height) {
+            JSAMPROW row_pointer[1];    /* pointer to JSAMPLE row[s] */
+
+            writer(oneRowP, srcRow, width, colors);
+            row_pointer[0] = oneRowP;
+            (void) jpeg_write_scanlines(&cinfo, row_pointer, 1);
+            srcRow = (const void*)((const char*)srcRow + bm.rowBytes());
+        }
+
+        jpeg_finish_compress(&cinfo);
+        jpeg_destroy_compress(&cinfo);
+
+        return true;
+    }
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+#include "SkTRegistry.h"
+
+static SkImageDecoder* DFactory(SkStream* stream) {
+    static const char gHeader[] = { 0xFF, 0xD8, 0xFF };
+    static const size_t HEADER_SIZE = sizeof(gHeader);
+
+    char buffer[HEADER_SIZE];
+    size_t len = stream->read(buffer, HEADER_SIZE);
+
+    if (len != HEADER_SIZE) {
+        return NULL;   // can't read enough
+    }
+    if (memcmp(buffer, gHeader, HEADER_SIZE)) {
+        return NULL;
+    }
+    return SkNEW(SkJPEGImageDecoder);
+}
+
+static SkImageEncoder* EFactory(SkImageEncoder::Type t) {
+    return (SkImageEncoder::kJPEG_Type == t) ? SkNEW(SkJPEGImageEncoder) : NULL;
+}
+
+static SkTRegistry<SkImageDecoder*, SkStream*> gDReg(DFactory);
+static SkTRegistry<SkImageEncoder*, SkImageEncoder::Type> gEReg(EFactory);