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// Copyright 2014 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.
#ifndef UI_VIEWS_VIEW_TARGETER_DELEGATE_H_
#define UI_VIEWS_VIEW_TARGETER_DELEGATE_H_
#include "base/macros.h"
#include "ui/views/views_export.h"
namespace gfx {
class Rect;
}
namespace views {
class View;
// Defines the default behaviour for hit-testing and event-targeting against a
// View using a rectangular region representing an event's location (i.e., the
// bounding box of a gesture or a 1x1 rect in the case of a mouse event). Views
// wishing to define custom hit-testing or event-targeting behaviour do so by
// extending ViewTargeterDelegate and then installing a ViewTargeter on
// themselves.
class VIEWS_EXPORT ViewTargeterDelegate {
public:
ViewTargeterDelegate() {}
virtual ~ViewTargeterDelegate() {}
// Returns true if |target| should be considered as a candidate target for
// an event having |rect| as its location, where |rect| is in the local
// coordinate space of |target|. Overrides of this method by a View subclass
// should enforce DCHECK_EQ(this, target).
// TODO(tdanderson): Consider changing the name of this method to better
// reflect its purpose.
virtual bool DoesIntersectRect(const View* target,
const gfx::Rect& rect) const;
// If point-based targeting should be used, return the deepest visible
// descendant of |root| that contains the center point of |rect|.
// If rect-based targeting (i.e., fuzzing) should be used, return the
// closest visible descendant of |root| having at least kRectTargetOverlap of
// its area covered by |rect|. If no such descendant exists, return the
// deepest visible descendant of |root| that contains the center point of
// |rect|. See http://goo.gl/3Jp2BD for more information about rect-based
// targeting.
virtual View* TargetForRect(View* root, const gfx::Rect& rect);
private:
DISALLOW_COPY_AND_ASSIGN(ViewTargeterDelegate);
};
} // namespace views
#endif // UI_VIEWS_VIEW_TARGETER_DELEGATE_H_
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