ui/views/cull_set.h

   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_CULL_SET_H_
   6 #define UI_VIEWS_CULL_SET_H_
   7
   8 #include "base/containers/hash_tables.h"
   9 #include "base/macros.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "ui/views/views_export.h"
  12
  13 namespace views {
  14
  15 class View;
  16
  17 // A CullSet defines a set of View pointers which have been possibly culled
  18 // from painting or other bounds-checking operations. It wraps a set of
  19 // pointers to views, or NULL if no such set is available.
  20 class VIEWS_EXPORT CullSet {
  21  public:
  22   // Default constructor builds a CullSet that will always return true for
  23   // ShouldPaint().
  24   CullSet();
  25   ~CullSet();
  26
  27   // Wraps a set of pointers to Views, as might be provided by
  28   // gfx::RTree::Query(), that intersect the damage rect and therefore need
  29   // to be painted. CullSet takes ownership of the provided pointer.
  30   CullSet(scoped_ptr<base::hash_set<intptr_t> > cull_set);
  31
  32   // Returns true if |view| needs to be painted.
  33   bool ShouldPaint(const View* view) const;
  34
  35  private:
  36   friend class BoundsTreeTestView;
  37
  38   // The set of Views that collided with the query rectangle provided to the
  39   // RTree data structure, or NULL if one is not available.
  40   scoped_ptr<base::hash_set<intptr_t> > cull_set_;
  41
  42   DISALLOW_COPY_AND_ASSIGN(CullSet);
  43 };
  44
  45 }  // namespace views
  46
  47 #endif  // UI_VIEWS_CULL_SET_H_