Canvas2d: Implement rerouting event by hit region's control.

third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  * Copyright (C) 2012, 2013 Intel Corporation. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
@@ skipping 24 matching lines @@
 #include "bindings/core/v8/ExceptionMessages.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ExceptionStatePlaceholder.h"
 #include "core/CSSPropertyNames.h"
 #include "core/css/StylePropertySet.h"
 #include "core/css/parser/CSSParser.h"
 #include "core/css/resolver/StyleResolver.h"
 #include "core/dom/AXObjectCache.h"
 #include "core/dom/StyleEngine.h"
 #include "core/events/Event.h"
+#include "core/events/MouseEvent.h"
 #include "core/frame/ImageBitmap.h"
 #include "core/frame/Settings.h"
 #include "core/html/HTMLVideoElement.h"
 #include "core/html/ImageData.h"
 #include "core/html/TextMetrics.h"
 #include "core/html/canvas/CanvasFontCache.h"
 #include "core/layout/LayoutBox.h"
 #include "core/layout/LayoutTheme.h"
 #include "modules/canvas2d/CanvasGradient.h"
 #include "modules/canvas2d/CanvasPattern.h"
@@ skipping 1734 matching lines @@
     }
 }
 
 void CanvasRenderingContext2D::styleDidChange(const ComputedStyle* oldStyle, const ComputedStyle& newStyle)
 {
     if (oldStyle && oldStyle->font() == newStyle.font())
         return;
     pruneLocalFontCache(0);
 }
 
+Node* CanvasRenderingContext2D::getControlAndUpdateEvent(Event& event)
+{
+    if (!event.isMouseEvent())
+        return nullptr;
+
+    MouseEvent& e = toMouseEvent(event);

[philipj_slow, 2016/02/01 04:05:20]

https://www.chromium.org/blink/coding-style#TOC-Names asks for full names in
general.

[zino, 2016/02/05 06:59:48]

Done.

+
+    Document& document = canvas()->document();
+    document.updateLayoutTreeForNodeIfNeeded(canvas());

[Justin Novosad, 2016/02/01 16:51:43]

Don't forget write a test that requires this update.

+
+    LayoutBox* box = canvas()->layoutBox();
+    FloatPoint localPos = box->absoluteToLocal(FloatPoint(e.absoluteLocation()), UseTransforms);
+    if (box->hasBorderOrPadding())
+        localPos.move(-box->contentBoxOffset());
+    localPos.scale(canvas()->width() / box->contentWidth(), canvas()->height() / box->contentHeight());

[Justin Novosad, 2016/02/01 16:51:42]

don't forget test cases that cover CSS zooming and hidpi (use
testRunner.setBackingScaleFactor)

+
+    HitRegion* hitRegion = hitRegionAtPoint(localPos);
+    if (hitRegion) {
+        e.setRegion(hitRegion->id());
+        if (hitRegion->control()) {
+            e.preventDefault();
+            e.setCancelBubble(true);
+            return hitRegion->control();
+        }
+    }
+    return nullptr;
+}
+
 String CanvasRenderingContext2D::textAlign() const
 {
     return textAlignName(state().textAlign());
 }
 
 void CanvasRenderingContext2D::setTextAlign(const String& s)
 {
     TextAlign align;
     if (!parseTextAlign(s, align))
         return;
@@ skipping 519 matching lines @@
         if (imageType == CanvasRenderingContext2DState::NonOpaqueImage)
             return;
         if (alpha < 0xFF)
             return;
     }
 
     canvas()->buffer()->willOverwriteCanvas();
 }
 
 } // namespace blink