WTL GDI extensions

wtlx.h

template<class T = HGDIOBJ>
  class COldObject {
  public:
    typedef T (WINAPI* restore)(HDC hdc, T old);

    COldObject(HDC dc, T old, restore func = SelectObject) : dc(dc), old(old), func(func) {}

    ~COldObject() {
      func(dc, (T)old);
    }

    operator T() const {
      return old;
    }

  private:
    T old;
    restore func;
    HDC dc;
  };
  typedef COldObject<HGDIOBJ> COldFont;
  typedef COldObject<HGDIOBJ> COldBitmap;
  typedef COldObject<HGDIOBJ> COldPen;
  typedef COldObject<HGDIOBJ> COldBrush;

  class COldBkMode : public COldObject<int> {
  public:
    COldBkMode(HDC hdc, int old) : COldObject<int>(hdc, old, SetBkMode) {}
  };

  class COldTextColor : public COldObject<COLORREF> {
  public:
    COldTextColor(HDC hdc, COLORREF old) : COldObject<COLORREF>(hdc, old, SetTextColor) {}
  };

  class COldBkColor : public COldObject<COLORREF> {
  public:
    COldBkColor(HDC hdc, COLORREF old) : COldObject<COLORREF>(hdc, old, SetBkColor) {}
  };

  /**
    Use this when you heavily manipulate a DC and want to restore its state quickly.

    @author_philk
  */
  class CSaveDC {
  public:
    CSaveDC(HDC hdc) : hdc(hdc), id(::SaveDC(hdc)) {}
    ~CSaveDC() {
      ATLVERIFY(::RestoreDC(hdc, id));
    }
  private:
    HDC hdc;
    const int id;
  };


// Usage
// WTL::COldFont oldFont(dc, dc.SelectFont(newFont));