1 files changed, 42 insertions, 6 deletions

diff --git a/src/images/SkJpegEncoder.cpp b/src/images/SkJpegEncoder.cpp
index fd88a5c8f6..d87fed81bc 100644
--- a/src/images/SkJpegEncoder.cpp
+++ b/src/images/SkJpegEncoder.cpp
@@ -35,7 +35,7 @@ public:
         return std::unique_ptr<SkJpegEncoderMgr>(new SkJpegEncoderMgr(stream));
     }
 
-    bool setParams(const SkImageInfo& srcInfo);
+    bool setParams(const SkImageInfo& srcInfo, const SkJpegEncoder::Options& options);
 
     jpeg_compress_struct* cinfo() { return &fCInfo; }
 
@@ -65,15 +65,36 @@ private:
     transform_scanline_proc fProc;
 };
 
-bool SkJpegEncoderMgr::setParams(const SkImageInfo& srcInfo) {
+bool SkJpegEncoderMgr::setParams(const SkImageInfo& srcInfo, const SkJpegEncoder::Options& options)
+{
+    auto chooseProc8888 = [&]() {
+        if (kUnpremul_SkAlphaType != srcInfo.alphaType() ||
+            SkJpegEncoder::AlphaOption::kIgnore == options.fAlphaOption)
+        {
+            return (transform_scanline_proc) nullptr;
+        }
+
+        // Note that kRespect mode is only supported with sRGB or linear transfer functions.
+        // The legacy code path is incidentally correct when the transfer function is linear.
+        const bool isSRGBTransferFn = srcInfo.gammaCloseToSRGB() &&
+                (SkTransferFunctionBehavior::kRespect == options.fBlendBehavior);
+        if (isSRGBTransferFn) {
+            return transform_scanline_to_premul_linear;
+        } else {
+            return transform_scanline_to_premul_legacy;
+        }
+    };
+
     J_COLOR_SPACE jpegColorType = JCS_EXT_RGBA;
     int numComponents = 0;
     switch (srcInfo.colorType()) {
         case kRGBA_8888_SkColorType:
+            fProc = chooseProc8888();
             jpegColorType = JCS_EXT_RGBA;
             numComponents = 4;
             break;
         case kBGRA_8888_SkColorType:
+            fProc = chooseProc8888();
             jpegColorType = JCS_EXT_BGRA;
             numComponents = 4;
             break;
@@ -83,11 +104,19 @@ bool SkJpegEncoderMgr::setParams(const SkImageInfo& srcInfo) {
             numComponents = 3;
             break;
         case kARGB_4444_SkColorType:
+            if (SkJpegEncoder::AlphaOption::kBlendOnBlack == options.fAlphaOption) {
+                return false;
+            }
+
             fProc = transform_scanline_444;
             jpegColorType = JCS_RGB;
             numComponents = 3;
             break;
         case kIndex_8_SkColorType:
+            if (SkJpegEncoder::AlphaOption::kBlendOnBlack == options.fAlphaOption) {
+                return false;
+            }
+
             fProc = transform_scanline_index8_opaque;
             jpegColorType = JCS_RGB;
             numComponents = 3;
@@ -98,11 +127,18 @@ bool SkJpegEncoderMgr::setParams(const SkImageInfo& srcInfo) {
             numComponents = 1;
             break;
         case kRGBA_F16_SkColorType:
-            if (!srcInfo.colorSpace() || !srcInfo.colorSpace()->gammaIsLinear()) {
+            if (!srcInfo.colorSpace() || !srcInfo.colorSpace()->gammaIsLinear() ||
+                    SkTransferFunctionBehavior::kRespect != options.fBlendBehavior) {
                 return false;
             }
 
-            fProc = transform_scanline_F16_to_8888;
+            if (kUnpremul_SkAlphaType != srcInfo.alphaType() ||
+                SkJpegEncoder::AlphaOption::kIgnore == options.fAlphaOption)
+            {
+                fProc = transform_scanline_F16_to_8888;
+            } else {
+                fProc = transform_scanline_F16_to_premul_8888;
+            }
             jpegColorType = JCS_EXT_RGBA;
             numComponents = 4;
             break;
@@ -125,7 +161,7 @@ bool SkJpegEncoderMgr::setParams(const SkImageInfo& srcInfo) {
 
 std::unique_ptr<SkJpegEncoder> SkJpegEncoder::Make(SkWStream* dst, const SkPixmap& src,
                                                    const Options& options) {
-    if (!SkPixmapIsValid(src, SkTransferFunctionBehavior::kIgnore)) {
+    if (!SkPixmapIsValid(src, options.fBlendBehavior)) {
         return nullptr;
     }
 
@@ -134,7 +170,7 @@ std::unique_ptr<SkJpegEncoder> SkJpegEncoder::Make(SkWStream* dst, const SkPixma
         return nullptr;
     }
 
-    if (!encoderMgr->setParams(src.info())) {
+    if (!encoderMgr->setParams(src.info(), options)) {
         return nullptr;
     }