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 UI_VIEWS_VIEW_TARGETER_DELEGATE_H_ 6 #define UI_VIEWS_VIEW_TARGETER_DELEGATE_H_ 7 8 #include "base/macros.h" 9 #include "ui/views/views_export.h" 10 11 namespace gfx { 12 class Rect; 13 } 14 15 namespace views { 16 class View; 17 18 // Defines the default behaviour for hit-testing and event-targeting against a 19 // View using a rectangular region representing an event's location. Views 20 // wishing to define custom hit-testing or event-targeting behaviour do so by 21 // extending ViewTargeterDelegate and then installing a ViewTargeter on 22 // themselves. 23 class VIEWS_EXPORT ViewTargeterDelegate { 24 public: ViewTargeterDelegate()25 ViewTargeterDelegate() {} ~ViewTargeterDelegate()26 virtual ~ViewTargeterDelegate() {} 27 28 // Returns true if the bounds of |target| intersects |rect|, where |rect| 29 // is in the local coodinate space of |target|. Overrides of this method by 30 // a View subclass should enforce DCHECK_EQ(this, target). 31 virtual bool DoesIntersectRect(const View* target, 32 const gfx::Rect& rect) const; 33 34 // If point-based targeting should be used, return the deepest visible 35 // descendant of |root| that contains the center point of |rect|. 36 // If rect-based targeting (i.e., fuzzing) should be used, return the 37 // closest visible descendant of |root| having at least kRectTargetOverlap of 38 // its area covered by |rect|. If no such descendant exists, return the 39 // deepest visible descendant of |root| that contains the center point of 40 // |rect|. See http://goo.gl/3Jp2BD for more information about rect-based 41 // targeting. 42 virtual View* TargetForRect(View* root, const gfx::Rect& rect); 43 44 private: 45 DISALLOW_COPY_AND_ASSIGN(ViewTargeterDelegate); 46 }; 47 48 } // namespace views 49 50 #endif // UI_VIEWS_VIEW_TARGETER_DELEGATE_H_ 51