Fix double CMYK->RGBA conversion on swizzled jpeg decodes

BUG=skia:

Change-Id: I4e8c4128f974cc491fcef0bbc1137b5d62b6f967
Reviewed-on: https://skia-review.googlesource.com/5933
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>

3 files changed, 15 insertions, 13 deletions

diff --git a/src/codec/SkJpegCodec.cpp b/src/codec/SkJpegCodec.cpp
index ad5ce5834d..8c2f5dc4e3 100644
--- a/src/codec/SkJpegCodec.cpp
+++ b/src/codec/SkJpegCodec.cpp
@@ -626,12 +626,14 @@ void SkJpegCodec::allocateStorage(const SkImageInfo& dstInfo) {
 }
 
 void SkJpegCodec::initializeSwizzler(const SkImageInfo& dstInfo, const Options& options) {
-    // libjpeg-turbo may have already performed color conversion.  We must indicate the
-    // appropriate format to the swizzler.
+    // libjpeg-turbo will handle format conversion from YUV to RGBA, BGRA, or 565.  fColorXform
+    // will handle format conversion from CMYK.  We only need the swizzler to perform format
+    // conversion when we have a CMYK image without a fColorXform.
+    bool skipFormatConversion = this->colorXform() ||
+                                (JCS_CMYK != fDecoderMgr->dinfo()->out_color_space);
+
     SkEncodedInfo swizzlerInfo = this->getEncodedInfo();
-    bool preSwizzled = true;
-    if (JCS_CMYK == fDecoderMgr->dinfo()->out_color_space) {
-        preSwizzled = false;
+    if (!skipFormatConversion) {
         swizzlerInfo = SkEncodedInfo::Make(SkEncodedInfo::kInvertedCMYK_Color,
                                            swizzlerInfo.alpha(),
                                            swizzlerInfo.bitsPerComponent());
@@ -647,7 +649,7 @@ void SkJpegCodec::initializeSwizzler(const SkImageInfo& dstInfo, const Options&
         swizzlerOptions.fSubset = &fSwizzlerSubset;
     }
     fSwizzler.reset(SkSwizzler::CreateSwizzler(swizzlerInfo, nullptr, dstInfo, swizzlerOptions,
-                                               nullptr, preSwizzled));
+                                               nullptr, skipFormatConversion));
     SkASSERT(fSwizzler);
 }
 
diff --git a/src/codec/SkSwizzler.cpp b/src/codec/SkSwizzler.cpp
index 0bbe824dc2..9cada7b39d 100644
--- a/src/codec/SkSwizzler.cpp
+++ b/src/codec/SkSwizzler.cpp
@@ -682,14 +682,14 @@ SkSwizzler* SkSwizzler::CreateSwizzler(const SkEncodedInfo& encodedInfo,
                                        const SkImageInfo& dstInfo,
                                        const SkCodec::Options& options,
                                        const SkIRect* frame,
-                                       bool preSwizzled) {
+                                       bool skipFormatConversion) {
     if (SkEncodedInfo::kPalette_Color == encodedInfo.color() && nullptr == ctable) {
         return nullptr;
     }
 
     RowProc fastProc = nullptr;
     RowProc proc = nullptr;
-    if (preSwizzled) {
+    if (skipFormatConversion) {
         switch (dstInfo.colorType()) {
             case kGray_8_SkColorType:
                 proc = &sample1;
@@ -1003,7 +1003,7 @@ SkSwizzler* SkSwizzler::CreateSwizzler(const SkEncodedInfo& encodedInfo,
 
     int srcBPP;
     const int dstBPP = SkColorTypeBytesPerPixel(dstInfo.colorType());
-    if (preSwizzled) {
+    if (skipFormatConversion) {
         srcBPP = dstBPP;
     } else {
         // Store bpp in bytes if it is an even multiple, otherwise use bits
diff --git a/src/codec/SkSwizzler.h b/src/codec/SkSwizzler.h
index 139ca4fd10..ebaed7ea33 100644
--- a/src/codec/SkSwizzler.h
+++ b/src/codec/SkSwizzler.h
@@ -27,9 +27,8 @@ public:
      *                 Contains partial scanline information.
      *  @param frame   Is non-NULL if the source pixels are part of an image
      *                 frame that is a subset of the full image.
-     *  @param preSwizzled Indicates that the codec has already swizzled to the
-     *                     destination format.  The swizzler only needs to sample
-     *                     and/or subset.
+     *  @param skipFormatConversion Indicates that we should skip format conversion.
+     *                              The swizzler only needs to sample and/or subset.
      *
      *  Note that a deeper discussion of partial scanline subsets and image frame
      *  subsets is below.  Currently, we do not support both simultaneously.  If
@@ -39,7 +38,8 @@ public:
      */
     static SkSwizzler* CreateSwizzler(const SkEncodedInfo& encodedInfo, const SkPMColor* ctable,
                                       const SkImageInfo& dstInfo, const SkCodec::Options&,
-                                      const SkIRect* frame = nullptr, bool preSwizzled = false);
+                                      const SkIRect* frame = nullptr,
+                                      bool skipFormatConversion = false);
 
     /**
      *  Swizzle a line. Generally this will be called height times, once