gfx/2d/AutoHelpersWin.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_gfx_AutoHelpersWin_h
   8 #define mozilla_gfx_AutoHelpersWin_h
   9
  10 #include <windows.h>
  11
  12 namespace mozilla {
  13 namespace gfx {
  14
  15 // Get the global device context, and auto-release it on destruction.
  16 class AutoDC {
  17  public:
  18   AutoDC() { mDC = ::GetDC(nullptr); }
  19
  20   ~AutoDC() { ::ReleaseDC(nullptr, mDC); }
  21
  22   HDC GetDC() { return mDC; }
  23
  24  private:
  25   HDC mDC;
  26 };
  27
  28 // Select a font into the given DC, and auto-restore.
  29 class AutoSelectFont {
  30  public:
  31   AutoSelectFont(HDC aDC, LOGFONTW* aLogFont) : mOwnsFont(false) {
  32     mFont = ::CreateFontIndirectW(aLogFont);
  33     if (mFont) {
  34       mOwnsFont = true;
  35       mDC = aDC;
  36       mOldFont = (HFONT)::SelectObject(aDC, mFont);
  37     } else {
  38       mOldFont = nullptr;
  39     }
  40   }
  41
  42   AutoSelectFont(HDC aDC, HFONT aFont) : mOwnsFont(false) {
  43     mDC = aDC;
  44     mFont = aFont;
  45     mOldFont = (HFONT)::SelectObject(aDC, aFont);
  46   }
  47
  48   ~AutoSelectFont() {
  49     if (mOldFont) {
  50       ::SelectObject(mDC, mOldFont);
  51       if (mOwnsFont) {
  52         ::DeleteObject(mFont);
  53       }
  54     }
  55   }
  56
  57   bool IsValid() const { return mFont != nullptr; }
  58
  59   HFONT GetFont() const { return mFont; }
  60
  61  private:
  62   HDC mDC;
  63   HFONT mFont;
  64   HFONT mOldFont;
  65   bool mOwnsFont;
  66 };
  67
  68 }  // namespace gfx
  69 }  // namespace mozilla
  70
  71 #endif  // mozilla_gfx_AutoHelpersWin_h