Use visual rects in DisplayItemList::AreaOfDrawText()

Bug: 1126582
Change-Id: Ie1c29eda2f7c05a96eef708041b15eed9de4d098
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2404398
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Tao Bai <michaelbai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#806064}

cc/paint/display_item_list.cc

@@ -119,22 +119,26 @@ void DisplayItemList::CaptureContent(const gfx::Rect& rect,
 }
 
 double DisplayItemList::AreaOfDrawText(const gfx::Rect& rect) const {
-  double area = 0;
   if (!paint_op_buffer_.has_draw_text_ops())
-    return area;
+    return 0;
   std::vector<size_t> offsets;
   std::vector<gfx::Rect> rects;
   rtree_.Search(rect, &offsets, &rects);
-  IterateTextContentByOffsets(
-      paint_op_buffer_, offsets, rects,
-      [&area](const DrawTextBlobOp* op, const gfx::Rect& rect) {
-        // TODO(wangxianzhu) : crbug.com/1126582 use the visual_rect from
-        // callback.
-        // This is not fully accurate, e.g. when there is transform operations,
-        // but is good for statistics purpose.
-        SkRect bounds = op->blob->bounds();
-        area += static_cast<double>(bounds.width()) * bounds.height();
-      });
+  DCHECK_EQ(offsets.size(), rects.size());
+
+  double area = 0;
+  size_t index = 0;
+  for (auto* op : PaintOpBuffer::OffsetIterator(&paint_op_buffer_, &offsets)) {
+    if (op->GetType() == PaintOpType::DrawTextBlob ||
+        // Don't walk into the record because the visual rect is already the
+        // bounding box of the sub paint operations. This works for most paint
+        // results for text generated by blink.
+        (op->GetType() == PaintOpType::DrawRecord &&
+         static_cast<DrawRecordOp*>(op)->record->has_draw_text_ops())) {
+      area += static_cast<double>(rects[index].width()) * rects[index].height();
+    }
+    ++index;
+  }
   return area;
 }
 

cc/paint/display_item_list_unittest.cc

@@ -1138,14 +1138,15 @@ TEST_F(DisplayItemListTest, AreaOfDrawText) {
   auto sub_list = base::MakeRefCounted<DisplayItemList>();
 
   auto text_blob1 = SkTextBlob::MakeFromString("ABCD", SkFont());
-  auto text_blob1_bounds = text_blob1->bounds();
-  auto text_blob1_area = text_blob1_bounds.width() * text_blob1_bounds.height();
+  gfx::Size text_blob1_size(ceilf(text_blob1->bounds().width()),
+                            ceilf(text_blob1->bounds().height()));
+  auto text_blob1_area = text_blob1_size.width() * text_blob1_size.height();
   auto text_blob2 = SkTextBlob::MakeFromString("EFG", SkFont());
-  auto text_blob2_bounds = text_blob2->bounds();
-  auto text_blob2_area = text_blob2_bounds.width() * text_blob2_bounds.height();
+  gfx::Size text_blob2_size(ceilf(text_blob2->bounds().width()),
+                            ceilf(text_blob2->bounds().height()));
+  auto text_blob2_area = text_blob2_size.width() * text_blob2_size.height();
 
   sub_list->StartPaint();
-  sub_list->push<DrawRectOp>(SkRect::MakeWH(100, 200), PaintFlags());
   sub_list->push<DrawTextBlobOp>(text_blob1, 0, 0, PaintFlags());
   sub_list->EndPaintOfUnpaired(gfx::Rect());
   auto record = sub_list->ReleaseAsRecord();
@@ -1155,22 +1156,24 @@ TEST_F(DisplayItemListTest, AreaOfDrawText) {
   list->push<TranslateOp>(100, 100);
   list->push<DrawRecordOp>(record);
   list->push<RestoreOp>();
-  list->EndPaintOfUnpaired(gfx::Rect(100, 100, 100, 200));
+  list->EndPaintOfUnpaired(gfx::Rect(gfx::Point(100, 100), text_blob1_size));
 
   list->StartPaint();
   list->push<SaveOp>();
   list->push<TranslateOp>(100, 400);
   list->push<DrawRecordOp>(record);
   list->push<RestoreOp>();
-  list->EndPaintOfUnpaired(gfx::Rect(100, 400, 100, 200));
+  list->EndPaintOfUnpaired(gfx::Rect(gfx::Point(100, 400), text_blob1_size));
 
   list->StartPaint();
-  list->push<DrawRectOp>(SkRect::MakeWH(100, 100), PaintFlags());
   list->push<DrawTextBlobOp>(text_blob2, 10, 20, PaintFlags());
-  list->EndPaintOfUnpaired(gfx::Rect(0, 0, 100, 100));
+  list->EndPaintOfUnpaired(gfx::Rect(text_blob2_size));
 
   list->StartPaint();
   list->push<DrawTextBlobOp>(text_blob2, 400, 100, PaintFlags());
+  list->EndPaintOfUnpaired(gfx::Rect(gfx::Point(400, 100), text_blob2_size));
+
+  list->StartPaint();
   list->push<DrawRectOp>(SkRect::MakeXYWH(400, 100, 100, 100), PaintFlags());
   list->EndPaintOfUnpaired(gfx::Rect(400, 100, 100, 100));
 
@@ -1178,10 +1181,10 @@ TEST_F(DisplayItemListTest, AreaOfDrawText) {
   // This includes the DrawTextBlobOp in the first DrawRecordOp the the first
   // direct DrawTextBlobOp.
   EXPECT_EQ(static_cast<int>(text_blob1_area + text_blob2_area),
-            static_cast<int>(list->AreaOfDrawText(gfx::Rect(0, 0, 200, 200))));
+            static_cast<int>(list->AreaOfDrawText(gfx::Rect(200, 200))));
   // This includes all DrawTextBlobOps.
   EXPECT_EQ(static_cast<int>(text_blob1_area * 2 + text_blob2_area * 2),
-            static_cast<int>(list->AreaOfDrawText(gfx::Rect(0, 0, 500, 500))));
+            static_cast<int>(list->AreaOfDrawText(gfx::Rect(500, 500))));
 }
 
 }  // namespace cc