Add color space xform support to SkJpegCodec (includes F16!)

src/codec/SkJpegCodec.h

Index: src/codec/SkJpegCodec.h
diff --git a/src/codec/SkJpegCodec.h b/src/codec/SkJpegCodec.h
index 7aa275ce4efd6028b69eb48d10de69e8a03a6f9b..7eb5100a8fadcfbd811aad5386c13426b56f20cf 100644
--- a/src/codec/SkJpegCodec.h
+++ b/src/codec/SkJpegCodec.h
@@ -10,6 +10,7 @@
 
 #include "SkCodec.h"
 #include "SkColorSpace.h"
+#include "SkColorSpaceXform.h"
 #include "SkImageInfo.h"
 #include "SkSwizzler.h"
 #include "SkStream.h"
@@ -99,34 +100,46 @@ private:
 
     /*
      * Checks if the conversion between the input image and the requested output
-     * image has been implemented
-     * Sets the output color space
+     * image has been implemented.
+     *
+     * Sets the output color space.
      */
-    bool setOutputColorSpace(const SkImageInfo& dst);
+    bool setOutputColorSpace(const SkImageInfo& dst, bool needsColorXform);
 
-    // scanline decoding
     void initializeSwizzler(const SkImageInfo& dstInfo, const Options& options);
+    bool initializeColorXform(const SkImageInfo& dstInfo, bool needsColorXform);
+    void allocateStorage(const SkImageInfo& dstInfo);
+    int readRows(const SkImageInfo& dstInfo, void* dst, size_t rowBytes, int count);
+
+    /*
+     * Scanline decoding.
+     */
     SkSampler* getSampler(bool createIfNecessary) override;
     Result onStartScanlineDecode(const SkImageInfo& dstInfo, const Options& options,
             SkPMColor ctable[], int* ctableCount) override;
     int onGetScanlines(void* dst, int count, size_t rowBytes) override;
     bool onSkipScanlines(int count) override;
 
-    SkAutoTDelete<JpegDecoderMgr> fDecoderMgr;
+    SkAutoTDelete<JpegDecoderMgr>      fDecoderMgr;
+
     // We will save the state of the decompress struct after reading the header.
     // This allows us to safely call onGetScaledDimensions() at any time.
-    const int                     fReadyState;
+    const int                          fReadyState;
+
+
+    SkAutoTMalloc<uint8_t>             fStorage;
+    uint8_t*                           fSwizzleSrcRow;
+    uint32_t*                          fColorXformSrcRow;

[mtklein, 2016/07/28 19:45:26]

Do we make sure the uint32_t* is 4 byte aligned into fStorage?

[msarett, 2016/07/28 20:09:45]

Should be fine because we always decode to RGBA (multiple of 4) when we do a
color xform.  But this result was more by luck than on purpose.  I've added an
SkASSERT.

 
-    // scanline decoding
-    SkAutoTMalloc<uint8_t>     fStorage;    // Only used if sampling is needed
-    uint8_t*                   fSrcRow;     // Only used if sampling is needed
     // libjpeg-turbo provides some subsetting.  In the case that libjpeg-turbo
     // cannot take the exact the subset that we need, we will use the swizzler
     // to further subset the output from libjpeg-turbo.
-    SkIRect                    fSwizzlerSubset;
-    SkAutoTDelete<SkSwizzler>  fSwizzler;
+    SkIRect                            fSwizzlerSubset;
+
+    SkAutoTDelete<SkSwizzler>          fSwizzler;
+    std::unique_ptr<SkColorSpaceXform> fColorXform;
     
-    sk_sp<SkData>              fICCData;
+    sk_sp<SkData>                      fICCData;
 
     typedef SkCodec INHERITED;
 };