Calculate correct cull rect for SVG inline text boxes.

third_party/WebKit/Source/core/paint/SVGInlineTextBoxPainterTest.cpp

Index: third_party/WebKit/Source/core/paint/SVGInlineTextBoxPainterTest.cpp
diff --git a/third_party/WebKit/Source/core/paint/SVGInlineTextBoxPainterTest.cpp b/third_party/WebKit/Source/core/paint/SVGInlineTextBoxPainterTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..7e2448528aef82efafe64ab26bc3b563dcf87121
--- /dev/null
+++ b/third_party/WebKit/Source/core/paint/SVGInlineTextBoxPainterTest.cpp
@@ -0,0 +1,110 @@
+// Copyright 2016 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 "core/paint/SVGInlineTextBoxPainter.h"
+
+#include "core/dom/Document.h"
+#include "core/dom/Range.h"
+#include "core/editing/DOMSelection.h"
+#include "core/frame/LocalDOMWindow.h"
+#include "core/layout/LayoutTestHelper.h"
+#include "core/layout/line/InlineTextBox.h"
+#include "core/paint/PaintLayer.h"
+#include "platform/graphics/GraphicsLayer.h"
+#include "platform/graphics/paint/DisplayItemList.h"
+#include "platform/graphics/paint/DrawingDisplayItem.h"
+#include "platform/graphics/paint/PaintController.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace blink {
+namespace {
+
+class SVGInlineTextBoxPainterTest : public RenderingTest {
+public:
+    SVGInlineTextBoxPainterTest() { }
+
+    const DrawingDisplayItem* getDrawingDisplayItem(int index)
+    {
+        const DisplayItemList& displayItemList = rootPaintController().getDisplayItemList();
+        return static_cast<const DrawingDisplayItem*>(&displayItemList[index]);
+    }
+
+    void selectAllText()
+    {
+        Range* range = document().createRange();
+        range->selectNode(document().documentElement());
+        LocalDOMWindow* window = document().domWindow();
+        DOMSelection* selection = window->getSelection();
+        selection->removeAllRanges();
+        selection->addRange(range);
+    }
+
+private:
+    PaintController& rootPaintController()
+    {
+        return document().view()->layoutView()->layer()->graphicsLayerBacking()->getPaintController();
+    }
+
+    void SetUp() override
+    {
+        RenderingTest::SetUp();
+        enableCompositing();
+    }
+};
+
+static void assertTextDrawingEquals(const DrawingDisplayItem* drawingDisplayItem, const char* str)
+{
+    ASSERT_EQ(str, static_cast<const InlineTextBox*>(&drawingDisplayItem->client())->text());
+}
+
+static void assertCullRectEquals(const DrawingDisplayItem* drawingDisplayItem, const IntRect& expectedRect)
+{
+    ASSERT_EQ(expectedRect, IntRect(drawingDisplayItem->picture()->cullRect()));
+}
+
+TEST_F(SVGInlineTextBoxPainterTest, TextCullRect_DefaultWritingMode)
+{
+    setBodyInnerHTML(
+        "<svg width='400px' height='400px' font-family='Arial' font-size='30'>"
+        "<text x='50' y='30'>x</text>"
+        "</svg>");
+    document().view()->updateAllLifecyclePhases();
+
+    const DrawingDisplayItem* drawingDisplayItem = getDrawingDisplayItem(4);
+    assertTextDrawingEquals(drawingDisplayItem, "x");
+    assertCullRectEquals(drawingDisplayItem, IntRect(50, 3, 15, 33));
+
+    selectAllText();
+    document().view()->updateAllLifecyclePhases();
+
+    drawingDisplayItem = getDrawingDisplayItem(5);
+    assertTextDrawingEquals(drawingDisplayItem, "x");
+    assertCullRectEquals(drawingDisplayItem, IntRect(50, 3, 15, 33));
+}
+
+TEST_F(SVGInlineTextBoxPainterTest, TextCullRect_WritingModeTopToBottom)
+{
+    setBodyInnerHTML(
+        "<svg width='400px' height='400px' font-family='Arial' font-size='30'>"
+        "<text x='50' y='30' writing-mode='tb'>x</text>"
+        "</svg>");
+    document().view()->updateAllLifecyclePhases();
+
+    const DrawingDisplayItem* drawingDisplayItem = getDrawingDisplayItem(4);
+    assertTextDrawingEquals(drawingDisplayItem, "x");
+    assertCullRectEquals(drawingDisplayItem, IntRect(33, 30, 34, 15));
+
+    selectAllText();
+    document().view()->updateAllLifecyclePhases();
+
+    // The selection rect is one pixel taller due to sub-pixel difference

[pdr., 2016/07/12 22:51:41]

This may be a bug.

[wkorman, 2016/07/12 23:33:20]

Yeah, let's discuss in person soon separately. I think it just means the cull
rect could be one pixel bigger than it needs to be when selected. But it could
also be correct to be so given anti-aliasing.

+    // between the text bounds and selection bounds in combination with use of
+    // enclosingIntRect() in SVGInlineTextBox::localSelectionRect().
+    drawingDisplayItem = getDrawingDisplayItem(5);
+    assertTextDrawingEquals(drawingDisplayItem, "x");
+    assertCullRectEquals(drawingDisplayItem, IntRect(33, 30, 34, 16));
+}
+
+} // namespace
+} // namespace blink