Modify deferred texture image API's handling of gamma

This tries to match the behavior you would see if you rendered directly to
a canvas without going through this round-trip. Specifically, mips are
built in the same way that they would be according to the context's
internal logic. To make things clearer, the user passes in the color space
of the destination surface, not our (internal) enum.

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=3526

Change-Id: If8c61500d34ae712227da0284f3a80cacf84113a
Reviewed-on: https://skia-review.googlesource.com/3526
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

2 files changed, 11 insertions, 2 deletions

diff --git a/src/image/SkImage.cpp b/src/image/SkImage.cpp
index 67779ba146..6c75619744 100644
--- a/src/image/SkImage.cpp
+++ b/src/image/SkImage.cpp
@@ -399,7 +399,7 @@ sk_sp<SkImage> SkImage::MakeFromTexture(GrContext*, const GrBackendTextureDesc&,
 size_t SkImage::getDeferredTextureImageData(const GrContextThreadSafeProxy&,
                                             const DeferredTextureImageUsageParams[],
                                             int paramCnt, void* buffer,
-                                            SkSourceGammaTreatment treatment) const {
+                                            SkColorSpace* dstColorSpace) const {
     return 0;
 }
 
diff --git a/src/image/SkImage_Gpu.cpp b/src/image/SkImage_Gpu.cpp
index af16681933..c9315bb14d 100644
--- a/src/image/SkImage_Gpu.cpp
+++ b/src/image/SkImage_Gpu.cpp
@@ -430,7 +430,7 @@ private:
 size_t SkImage::getDeferredTextureImageData(const GrContextThreadSafeProxy& proxy,
                                             const DeferredTextureImageUsageParams params[],
                                             int paramCnt, void* buffer,
-                                            SkSourceGammaTreatment gammaTreatment) const {
+                                            SkColorSpace* dstColorSpace) const {
     // Extract relevant min/max values from the params array.
     int lowestPreScaleMipLevel = params[0].fPreScaleMipLevel;
     SkFilterQuality highestFilterQuality = params[0].fQuality;
@@ -565,6 +565,15 @@ size_t SkImage::getDeferredTextureImageData(const GrContextThreadSafeProxy& prox
         memcpy(ct, pixmap.ctable()->readColors(), ctSize);
     }
 
+    // If the context has sRGB support, and we're intending to render to a surface with an attached
+    // color space, and the image has an sRGB-like color space attached, then use our gamma (sRGB)
+    // aware mip-mapping.
+    SkSourceGammaTreatment gammaTreatment = SkSourceGammaTreatment::kIgnore;
+    if (proxy.fCaps->srgbSupport() && SkToBool(dstColorSpace) &&
+        info.colorSpace() && info.colorSpace()->gammaCloseToSRGB()) {
+        gammaTreatment = SkSourceGammaTreatment::kRespect;
+    }
+
     SkASSERT(info == pixmap.info());
     size_t rowBytes = pixmap.rowBytes();
     static_assert(std::is_standard_layout<DeferredTextureImage>::value,