1// Copyright 2014 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef MouseEventHitRegion_h
6#define MouseEventHitRegion_h
7
8#include "core/events/MouseEvent.h"
9#include "core/html/HTMLCanvasElement.h"
10#include "core/html/canvas/CanvasRenderingContext.h"
11#include "core/html/canvas/CanvasRenderingContext2D.h"
12
13namespace blink {
14
15class MouseEventHitRegion {
16public:
17    static String region(MouseEvent& event)
18    {
19        if (!event.target() || !isHTMLCanvasElement(event.target()->toNode()))
20            return String();
21
22        HTMLCanvasElement* canvas = toHTMLCanvasElement(event.target()->toNode());
23        CanvasRenderingContext* context = canvas->renderingContext();
24        if (!context || !context->is2d())
25            return String();
26
27        HitRegion* hitRegion = toCanvasRenderingContext2D(context)->
28            hitRegionAtPoint(LayoutPoint(event.offsetX(), event.offsetY()));
29
30        if (!hitRegion)
31            return String();
32
33        String id = hitRegion->id();
34        if (id.isEmpty())
35            return String();
36
37        return id;
38    }
39};
40
41} // namespace blink
42
43#endif
44