cc: Add image decode control in the compositor.

cc/playback/discardable_image_map.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/playback/discardable_image_map.h"
 
 #include <algorithm>
 #include <limits>
 
+#include "base/containers/adapters.h"
 #include "cc/base/math_util.h"
 #include "cc/playback/display_item_list.h"
 #include "third_party/skia/include/utils/SkNWayCanvas.h"
 #include "ui/gfx/geometry/rect_conversions.h"
 #include "ui/gfx/skia_util.h"
 
 namespace cc {
 
-namespace {
-
 SkRect MapRect(const SkMatrix& matrix, const SkRect& src) {
   SkRect dst;
   matrix.mapRect(&dst, src);
   return dst;
 }
 
-SkSize ExtractScale(const SkMatrix& matrix) {
-  SkSize scale = SkSize::Make(matrix.getScaleX(), matrix.getScaleY());
+bool ExtractScale(const SkMatrix& matrix, SkSize* scale) {
+  *scale = SkSize::Make(matrix.getScaleX(), matrix.getScaleY());
   if (matrix.getType() & SkMatrix::kAffine_Mask) {
-    if (!matrix.decomposeScale(&scale))
-      scale.set(1, 1);
+    if (!matrix.decomposeScale(scale)) {
+      scale->set(1, 1);
+      return false;
+    }
   }
-  return scale;
+  return true;
 }
 
+bool ComputeNewRectFromPaintBounds(
+    const SkRect& rect,
+    const SkPaint* paint,
+    const std::vector<const SkPaint*>& saved_paints,
+    SkRect* paint_bounds) {
+  *paint_bounds = rect;
+  if (paint) {
+    if (!paint->canComputeFastBounds())
+      return false;
+    *paint_bounds = paint->computeFastBounds(*paint_bounds, paint_bounds);
+  }
+
+  for (const auto* paint : base::Reversed(saved_paints)) {
+    if (!paint)
+      continue;
+    if (!paint->canComputeFastBounds())
+      return false;
+    *paint_bounds = paint->computeFastBounds(*paint_bounds, paint_bounds);
+  }
+  return true;
+}
+
+namespace {
+
 // We're using an NWay canvas with no added canvases, so in effect
 // non-overridden functions are no-ops.
 class DiscardableImagesMetadataCanvas : public SkNWayCanvas {
  public:
   DiscardableImagesMetadataCanvas(
       int width,
       int height,
       std::vector<std::pair<DrawImage, gfx::Rect>>* image_set)
       : SkNWayCanvas(width, height),
         image_set_(image_set),
         canvas_bounds_(SkRect::MakeIWH(width, height)) {}
 
  protected:
   // we need to "undo" the behavior of SkNWayCanvas, which will try to forward
   // it.
   void onDrawPicture(const SkPicture* picture,
                      const SkMatrix* matrix,
                      const SkPaint* paint) override {
     SkCanvas::onDrawPicture(picture, matrix, paint);
   }
 
   void onDrawImage(const SkImage* image,
                    SkScalar x,
                    SkScalar y,
                    const SkPaint* paint) override {
-    const SkMatrix& ctm = this->getTotalMatrix();
-    AddImage(image, MapRect(ctm, SkRect::MakeXYWH(x, y, image->width(),
-                                                  image->height())),
-             ctm, paint);
+    const SkMatrix& ctm = getTotalMatrix();
+    AddImage(
+        image, SkRect::MakeIWH(image->width(), image->height()),
+        MapRect(ctm, SkRect::MakeXYWH(x, y, image->width(), image->height())),
+        ctm, paint);
   }
 
   void onDrawImageRect(const SkImage* image,
                        const SkRect* src,
                        const SkRect& dst,
                        const SkPaint* paint,
                        SrcRectConstraint) override {
-    const SkMatrix& ctm = this->getTotalMatrix();
+    const SkMatrix& ctm = getTotalMatrix();
     SkRect src_storage;
     if (!src) {
       src_storage = SkRect::MakeIWH(image->width(), image->height());
       src = &src_storage;
     }
     SkMatrix matrix;
     matrix.setRectToRect(*src, dst, SkMatrix::kFill_ScaleToFit);
     matrix.postConcat(ctm);
-    AddImage(image, MapRect(ctm, dst), matrix, paint);
+    AddImage(image, *src, MapRect(ctm, dst), matrix, paint);
   }
 
   void onDrawImageNine(const SkImage* image,
                        const SkIRect& center,
                        const SkRect& dst,
                        const SkPaint* paint) override {
-    AddImage(image, dst, this->getTotalMatrix(), paint);
+    // TODO(vmpstr): This should be storing 9 different images here, probably to
+    // allow for sub-image scaling.
+    AddImage(image, SkRect::MakeIWH(image->width(), image->height()), dst,
+             getTotalMatrix(), paint);
+  }
+
+  SaveLayerStrategy willSaveLayer(const SkRect* rect,
+                                  const SkPaint* paint,
+                                  SaveFlags save_flags) override {
+    saved_paints_.push_back(paint);
+    return SkNWayCanvas::willSaveLayer(rect, paint, save_flags);
+  }
+
+  void willSave() override {
+    saved_paints_.push_back(nullptr);
+    return SkNWayCanvas::willSave();
+  }
+
+  void willRestore() override {
+    DCHECK_GT(saved_paints_.size(), 0u);
+    saved_paints_.pop_back();
+    SkNWayCanvas::willRestore();
   }
 
  private:
   void AddImage(const SkImage* image,
+                const SkRect& src_rect,
                 const SkRect& rect,
                 const SkMatrix& matrix,
                 const SkPaint* paint) {
-    if (rect.intersects(canvas_bounds_) && image->isLazyGenerated()) {
-      SkFilterQuality filter_quality = kNone_SkFilterQuality;
-      if (paint) {
-        filter_quality = paint->getFilterQuality();
-      }
-      image_set_->push_back(
-          std::make_pair(DrawImage(image, ExtractScale(matrix), filter_quality),
-                         gfx::ToEnclosingRect(gfx::SkRectToRectF(rect))));
+    if (!image->isLazyGenerated())
+      return;
+
+    SkRect paint_rect;
+    bool computed_paint_bounds = ComputePaintBounds(rect, paint, &paint_rect);
+    if (!computed_paint_bounds) {
+      // TODO(vmpstr): UMA this case.
+      paint_rect = canvas_bounds_;
     }
+
+    if (!paint_rect.intersects(canvas_bounds_))
+      return;
+
+    SkFilterQuality filter_quality = kNone_SkFilterQuality;
+    if (paint) {
+      filter_quality = paint->getFilterQuality();
+    }
+
+    SkIRect src_irect;
+    src_rect.roundOut(&src_irect);
+    SkSize scale;
+    bool is_decomposable = ExtractScale(matrix, &scale);
+    image_set_->push_back(
+        std::make_pair(DrawImage(image, src_irect, scale, filter_quality,
+                                 matrix.hasPerspective(), is_decomposable),
+                       gfx::ToEnclosingRect(gfx::SkRectToRectF(paint_rect))));
+  }
+
+  bool ComputePaintBounds(const SkRect& rect,
+                          const SkPaint* paint,
+                          SkRect* paint_bounds) {
+    return ComputeNewRectFromPaintBounds(rect, paint, saved_paints_,
+                                         paint_bounds);
   }
 
   std::vector<std::pair<DrawImage, gfx::Rect>>* image_set_;
   const SkRect canvas_bounds_;
+  std::vector<const SkPaint*> saved_paints_;
 };
 
 }  // namespace
 
 DiscardableImageMap::DiscardableImageMap() {}
 
 DiscardableImageMap::~DiscardableImageMap() {}
 
 scoped_ptr<SkCanvas> DiscardableImageMap::BeginGeneratingMetadata(
     const gfx::Size& bounds) {
@@ skipping 23 matching lines @@
     DiscardableImageMap* image_map,
     const gfx::Size& bounds)
     : image_map_(image_map),
       metadata_canvas_(image_map->BeginGeneratingMetadata(bounds)) {}
 
 DiscardableImageMap::ScopedMetadataGenerator::~ScopedMetadataGenerator() {
   image_map_->EndGeneratingMetadata();
 }
 
 }  // namespace cc