base/win/scoped_select_object.h

   1 // Copyright (c) 2011 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 BASE_WIN_SCOPED_SELECT_OBJECT_H_
   6 #define BASE_WIN_SCOPED_SELECT_OBJECT_H_
   7
   8 #include <windows.h>
   9
  10 #include "base/basictypes.h"
  11 #include "base/logging.h"
  12
  13 namespace base {
  14 namespace win {
  15
  16 // Helper class for deselecting object from DC.
  17 class ScopedSelectObject {
  18  public:
  19   ScopedSelectObject(HDC hdc, HGDIOBJ object)
  20       : hdc_(hdc),
  21         oldobj_(SelectObject(hdc, object)) {
  22     DCHECK(hdc_);
  23     DCHECK(object);
  24     DCHECK(oldobj_ != NULL && oldobj_ != HGDI_ERROR);
  25   }
  26
  27   ~ScopedSelectObject() {
  28     HGDIOBJ object = SelectObject(hdc_, oldobj_);
  29     DCHECK((GetObjectType(oldobj_) != OBJ_REGION && object != NULL) ||
  30            (GetObjectType(oldobj_) == OBJ_REGION && object != HGDI_ERROR));
  31   }
  32
  33  private:
  34   HDC hdc_;
  35   HGDIOBJ oldobj_;
  36
  37   DISALLOW_COPY_AND_ASSIGN(ScopedSelectObject);
  38 };
  39
  40 }  // namespace win
  41 }  // namespace base
  42
  43 #endif  // BASE_WIN_SCOPED_SELECT_OBJECT_H_