Optimize SkColorSpaceXformCanvas for GPU-acceleration

This change ensures that SkImages are uploaded to the GPU before
applying the xform when the destination canvas is on the GPU. This
makes it possible to get hits in the texture cache and it ensures
that transforms get computed on the GPU.

This fixes a severe performance regression in Chrome that happened
when color correction was enabled.

Associated chromium patch for layout test rebaselines:
https://chromium-review.googlesource.com/c/chromium/src/+/655483

Merge dependency: Merging this change to the M-62 and M-61
branches also requires merging the following change, otherwise
there will be rendering errors:
https://skia-review.googlesource.com/c/skia/+/43562

BUG=chromium:760738

Change-Id: I49fd5ef7968272d311249c3824fe15bee4648b73
Reviewed-on: https://skia-review.googlesource.com/43183
Commit-Queue: Justin Novosad <junov@chromium.org>
Reviewed-by: Brian Osman <brianosman@google.com>

1 files changed, 21 insertions, 5 deletions

diff --git a/src/core/SkColorSpaceXformCanvas.cpp b/src/core/SkColorSpaceXformCanvas.cpp
index 6d6d27b399..dc36d36716 100644
--- a/src/core/SkColorSpaceXformCanvas.cpp
+++ b/src/core/SkColorSpaceXformCanvas.cpp
@@ -139,25 +139,25 @@ public:
     void onDrawImage(const SkImage* img,
                      SkScalar l, SkScalar t,
                      const SkPaint* paint) override {
-        fTarget->drawImage(fXformer->apply(img).get(), l, t, MaybePaint(paint, fXformer.get()));
+        fTarget->drawImage(prepareImage(img).get(), l, t, MaybePaint(paint, fXformer.get()));
     }
     void onDrawImageRect(const SkImage* img,
                          const SkRect* src, const SkRect& dst,
                          const SkPaint* paint, SrcRectConstraint constraint) override {
-        fTarget->drawImageRect(fXformer->apply(img).get(),
+        fTarget->drawImageRect(prepareImage(img).get(),
                                src ? *src : SkRect::MakeIWH(img->width(), img->height()), dst,
                                MaybePaint(paint, fXformer.get()), constraint);
     }
     void onDrawImageNine(const SkImage* img,
                          const SkIRect& center, const SkRect& dst,
                          const SkPaint* paint) override {
-        fTarget->drawImageNine(fXformer->apply(img).get(), center, dst,
+        fTarget->drawImageNine(prepareImage(img).get(), center, dst,
                                MaybePaint(paint, fXformer.get()));
     }
     void onDrawImageLattice(const SkImage* img,
                             const Lattice& lattice, const SkRect& dst,
                             const SkPaint* paint) override {
-        fTarget->drawImageLattice(fXformer->apply(img).get(), lattice, dst,
+        fTarget->drawImageLattice(prepareImage(img).get(), lattice, dst,
                                   MaybePaint(paint, fXformer.get()));
     }
     void onDrawAtlas(const SkImage* atlas, const SkRSXform* xforms, const SkRect* tex,
@@ -169,7 +169,7 @@ public:
             fXformer->apply(xformed.begin(), colors, count);
             colors = xformed.begin();
         }
-        fTarget->drawAtlas(fXformer->apply(atlas).get(), xforms, tex, colors, count, mode, cull,
+        fTarget->drawAtlas(prepareImage(atlas).get(), xforms, tex, colors, count, mode, cull,
                            MaybePaint(paint, fXformer.get()));
     }
 
@@ -308,6 +308,22 @@ public:
     void onFlush() override { return fTarget->flush(); }
 
 private:
+    sk_sp<SkImage> prepareImage(const SkImage* image) {
+        GrContext* gr = fTarget->getGrContext();
+        if (gr) {
+            // If fTarget is GPU-accelerated, we want to upload to a texture
+            // before applying the transform. This way, we can get cache hits
+            // in the texture cache and the transform gets applied on the GPU.
+            sk_sp<SkImage> textureImage = image->makeTextureImage(gr, nullptr);
+            if (textureImage)
+                return fXformer->apply(textureImage.get());
+        }
+        // TODO: Extract a sub image corresponding to the src rect in order
+        // to xform only the useful part of the image. Sub image could be reduced
+        // even further by taking into account dst_rect+ctm+clip
+        return fXformer->apply(image);
+    }
+
     bool skipXform(const SkBitmap& bitmap) {
         return (!bitmap.colorSpace() && fTargetCS->isSRGB()) ||
                (SkColorSpace::Equals(bitmap.colorSpace(), fTargetCS.get())) ||