include/vcl/scopedbitmapaccess.hxx

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  19
  20 #ifndef INCLUDED_VCL_SCOPEDBITMAPACCESS_HXX
  21 #define INCLUDED_VCL_SCOPEDBITMAPACCESS_HXX
  22
  23 #include <sal/types.h>
  24
  25 namespace vcl
  26 {
  27
  28 /** This template handles BitmapAccess the RAII way.
  29
  30     Please don't use directly, but through the ready-made typedefs
  31     ScopedReadAccess and ScopedWriteAccess in classes Bitmap and
  32     AlphaMask.
  33
  34     Use as follows:
  35     Bitmap aBitmap;
  36     Bitmap::ScopedReadAccess pReadAccess( aBitmap );
  37     pReadAccess->SetPixel()...
  38
  39     Bitmap aBitmap2;
  40     BitmapScopedWriteAccess pWriteAccess( bCond ? aBitmap2.AcquireWriteAccess() : 0, aBitmap2 );
  41     if ( pWriteAccess )...
  42
  43     @attention for practical reasons, ScopedBitmapAccess stores a
  44     reference to the provided bitmap, thus, make sure that the bitmap
  45     specified at construction time lives at least as long as the
  46     ScopedBitmapAccess.
  47  */
  48 template < class Access, class Bitmap, Access* (Bitmap::* Acquire)() > class ScopedBitmapAccess
  49 {
  50 public:
  51     explicit ScopedBitmapAccess( Bitmap& rBitmap ) :
  52         mpAccess( nullptr ),
  53         mpBitmap( &rBitmap )
  54     {
  55         mpAccess = (mpBitmap->*Acquire)();
  56     }
  57
  58     ScopedBitmapAccess( Access* pAccess, Bitmap& rBitmap ) :
  59         mpAccess( pAccess ),
  60         mpBitmap( &rBitmap )
  61     {
  62     }
  63
  64     ScopedBitmapAccess( ) :
  65         mpAccess( nullptr ),
  66         mpBitmap( nullptr )
  67     {
  68     }
  69
  70     // Move semantics
  71     ScopedBitmapAccess &operator=(ScopedBitmapAccess&&other)
  72     {
  73         mpAccess=other.mpAccess;
  74         mpBitmap=other.mpBitmap;
  75         other.mpAccess = nullptr;
  76         other.mpBitmap = nullptr;
  77         return *this;
  78      }
  79
  80     // Disable copy from lvalue.
  81     ScopedBitmapAccess(const ScopedBitmapAccess&) = delete;
  82     ScopedBitmapAccess &operator=(const ScopedBitmapAccess&) = delete;
  83
  84     ~ScopedBitmapAccess() COVERITY_NOEXCEPT_FALSE
  85     {
  86         if (mpAccess)
  87            mpBitmap->ReleaseAccess( mpAccess );
  88     }
  89
  90     void reset()
  91     {
  92         if (mpAccess)
  93         {
  94            mpBitmap->ReleaseAccess( mpAccess );
  95            mpAccess = nullptr;
  96         }
  97     }
  98
  99     bool operator!() const { return !mpAccess; }
 100     explicit operator bool() const
 101     {
 102         return mpAccess;
 103     }
 104
 105     Access*         get() { return mpAccess; }
 106     const Access*   get() const { return mpAccess; }
 107
 108     Access*         operator->() { return mpAccess; }
 109     const Access*   operator->() const { return mpAccess; }
 110
 111     Access&         operator*() { return *mpAccess; }
 112     const Access&   operator*() const { return *mpAccess; }
 113
 114 private:
 115     Access*     mpAccess;
 116     Bitmap*     mpBitmap;
 117 };
 118
 119 }
 120
 121 #endif // INCLUDED_VCL_SCOPEDBITMAPACCESS_HXX
 122
 123 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */