canvas/source/vcl/bitmapbackbuffer.hxx

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  30
  31 #ifndef _VCLCANVAS_BITMAPBACKBUFFER_HXX_
  32 #define _VCLCANVAS_BITMAPBACKBUFFER_HXX_
  33
  34 #include <vcl/virdev.hxx>
  35 #include <vcl/bitmapex.hxx>
  36
  37 #include <canvas/vclwrapper.hxx>
  38 #include "outdevprovider.hxx"
  39
  40 #include <boost/shared_ptr.hpp>
  41
  42
  43 namespace vclcanvas
  44 {
  45     /** Backbuffer implementation for canvas bitmap.
  46
  47         This class abstracts away the renderable bitmap for the bitmap
  48         canvas. The actual VirtualDevice is only created when
  49         necessary, which makes read-only bitmaps a lot smaller.
  50     */
  51     class BitmapBackBuffer : public OutDevProvider
  52     {
  53     public:
  54         /** Create a backbuffer for given reference device
  55          */
  56         BitmapBackBuffer( const BitmapEx&               rBitmap,
  57                           const OutputDevice&   rRefDevice );
  58
  59         ~BitmapBackBuffer();
  60
  61         virtual OutputDevice&           getOutDev();
  62         virtual const OutputDevice& getOutDev() const;
  63
  64         /// Clear the underlying bitmap to white, all transparent
  65         void clear();
  66
  67         /** Exposing our internal bitmap. Only to be used from
  68             CanvasBitmapHelper
  69
  70             @internal
  71         */
  72         BitmapEx&                                       getBitmapReference();
  73         Size                                            getBitmapSizePixel() const;
  74
  75     private:
  76         void createVDev() const;
  77         void updateVDev() const;
  78
  79         ::canvas::vcltools::VCLObject<BitmapEx> maBitmap;
  80         mutable VirtualDevice*                                  mpVDev; // created only on demand
  81
  82         const OutputDevice&                                     mrRefDevice;
  83
  84         /** When true, the bitmap contains the last valid
  85             content. When false, and mbVDevContentIsCurrent is true,
  86             the VDev contains the last valid content (which must be
  87             copied back to the bitmap, when getBitmapReference() is
  88             called). When both are false, this object is just
  89             initialized.
  90          */
  91         mutable bool                                                    mbBitmapContentIsCurrent;
  92
  93         /** When true, and mpVDev is non-NULL, the VDev contains the
  94             last valid content. When false, and
  95             mbBitmapContentIsCurrent is true, the bitmap contains the
  96             last valid content. When both are false, this object is
  97             just initialized.
  98          */
  99         mutable bool                                                    mbVDevContentIsCurrent;
 100     };
 101
 102     typedef ::boost::shared_ptr< BitmapBackBuffer > BitmapBackBufferSharedPtr;
 103
 104 }
 105
 106 #endif /* #ifndef _VCLCANVAS_BITMAPBACKBUFFER_HXX_ */
 107