WIP: <canvas> hit regions

Source/core/html/canvas/CanvasRenderingContext2D.cpp

Index: Source/core/html/canvas/CanvasRenderingContext2D.cpp
diff --git a/Source/core/html/canvas/CanvasRenderingContext2D.cpp b/Source/core/html/canvas/CanvasRenderingContext2D.cpp
index 8456aba1db2b4de549857a809bf166dec4e1618a..19a827eaa1f77788a8b4b23128a3d546d2f060b3 100644
--- a/Source/core/html/canvas/CanvasRenderingContext2D.cpp
+++ b/Source/core/html/canvas/CanvasRenderingContext2D.cpp
@@ -52,6 +52,7 @@
 #include "core/html/ImageData.h"
 #include "core/html/TextMetrics.h"
 #include "core/html/canvas/CanvasGradient.h"
+#include "core/html/canvas/CanvasHitRegion.h"
 #include "core/html/canvas/CanvasPattern.h"
 #include "core/html/canvas/CanvasStyle.h"
 #include "core/html/canvas/Path2D.h"
@@ -86,6 +87,7 @@ static bool contextLostRestoredEventsEnabled()
 
 CanvasRenderingContext2D::CanvasRenderingContext2D(HTMLCanvasElement* canvas, const Canvas2DContextAttributes* attrs, bool usesCSSCompatibilityParseMode)
     : CanvasRenderingContext(canvas)
+    , m_hitRegionManager(CanvasHitRegionManager::create())
     , m_usesCSSCompatibilityParseMode(usesCSSCompatibilityParseMode)
     , m_hasAlpha(!attrs || attrs->alpha())
     , m_isContextLost(false)
@@ -166,6 +168,7 @@ void CanvasRenderingContext2D::trace(Visitor* visitor)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_stateStack);
+    visitor->trace(m_hitRegionManager);
     visitor->trace(m_fetchedFonts);
 #endif
     CanvasRenderingContext::trace(visitor);
@@ -230,6 +233,7 @@ void CanvasRenderingContext2D::reset()
     m_stateStack.resize(1);
     m_stateStack.first() = adoptPtrWillBeNoop(new State());
     m_path.clear();
+    m_hitRegionManager->clear();
 }
 
 // Important: Several of these properties are also stored in GraphicsContext's
@@ -1216,6 +1220,8 @@ void CanvasRenderingContext2D::clearRect(float x, float y, float width, float he
     if (!computeDirtyRect(rect, &dirtyRect))
         return;
 
+    m_hitRegionManager->removeEnclosed(rect, state().m_transform);
+
     bool saved = false;
     if (shouldDrawShadows()) {
         context->save();
@@ -2266,6 +2272,45 @@ PassRefPtr<Canvas2DContextAttributes> CanvasRenderingContext2D::getContextAttrib
     return attributes.release();
 }
 
+void CanvasRenderingContext2D::addHitRegion(ExceptionState& exceptionState)
+{
+    DecodedHitRegionOptions decodedOptions;
+    decodedOptions.resolvePath(m_path, state().m_transform);
+    // parentId / id will be null here, so no need to resolve them.
+
+    addHitRegionInternal(decodedOptions, exceptionState);
+}
+
+void CanvasRenderingContext2D::addHitRegion(const Dictionary& options, ExceptionState& exceptionState)
+{
+    DecodedHitRegionOptions decodedOptions(options);
+    decodedOptions.resolvePath(m_path, state().m_transform);
+    decodedOptions.resolveIds(m_hitRegionManager.get());
+
+    addHitRegionInternal(decodedOptions, exceptionState);
+}
+
+void CanvasRenderingContext2D::removeHitRegion(const String& id)
+{
+    if (CanvasHitRegion* hitRegion = m_hitRegionManager->getHitRegionById(id))
+        m_hitRegionManager->remove(hitRegion);
+}
+
+CanvasHitRegion* CanvasRenderingContext2D::hitRegionAtPoint(const LayoutPoint& point)
+{
+    return m_hitRegionManager->getHitRegionAtPoint(point);
+}
+
+void CanvasRenderingContext2D::addHitRegionInternal(const DecodedHitRegionOptions& options, ExceptionState& exceptionState)
+{
+    if (!options.validate(exceptionState))
+        return;
+
+    RefPtrWillBeRawPtr<CanvasHitRegion> hitRegion = CanvasHitRegion::create(options);
+    m_hitRegionManager->remove(options.previousHitRegion.get());
+    m_hitRegionManager->add(hitRegion.release());
+}
+
 void CanvasRenderingContext2D::drawFocusIfNeeded(Element* element)
 {
     drawFocusIfNeededInternal(m_path, element);