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      1 /*
      2  * Copyright (C) 2012 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #ifndef HWndDC_h
     27 #define HWndDC_h
     28 
     29 #include <windows.h>
     30 #include "wtf/NonCopyable.h"
     31 
     32 namespace blink {
     33 
     34 class HWndDC {
     35     WTF_MAKE_NONCOPYABLE(HWndDC);
     36 public:
     37     HWndDC()
     38         : m_hwnd(0)
     39         , m_hdc(0)
     40     {
     41     }
     42 
     43     explicit HWndDC(HWND hwnd)
     44         : m_hwnd(hwnd)
     45         , m_hdc(::GetDC(hwnd))
     46     {
     47     }
     48 
     49     HWndDC(HWND hwnd, HRGN hrgnClip, DWORD flags)
     50         : m_hwnd(hwnd)
     51         , m_hdc(::GetDCEx(hwnd, hrgnClip, flags))
     52     {
     53     }
     54 
     55     ~HWndDC()
     56     {
     57         clear();
     58     }
     59 
     60     HDC setHWnd(HWND hwnd)
     61     {
     62         clear();
     63         m_hwnd = hwnd;
     64         m_hdc = ::GetDC(hwnd);
     65         return m_hdc;
     66     }
     67 
     68     void clear()
     69     {
     70         if (!m_hdc)
     71             return;
     72         ::ReleaseDC(m_hwnd, m_hdc);
     73         m_hwnd = 0;
     74         m_hdc = 0;
     75     }
     76 
     77     operator HDC()
     78     {
     79         return m_hdc;
     80     }
     81 
     82 private:
     83     HWND m_hwnd;
     84     HDC m_hdc;
     85 };
     86 
     87 } // namespace blink
     88 
     89 #endif // HWndDC_h
     90