canvas/source/vcl/bitmapbackbuffer.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
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  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #ifndef INCLUDED_CANVAS_SOURCE_VCL_BITMAPBACKBUFFER_HXX
  21 #define INCLUDED_CANVAS_SOURCE_VCL_BITMAPBACKBUFFER_HXX
  22
  23 #include <vcl/virdev.hxx>
  24 #include <vcl/bitmapex.hxx>
  25
  26 #include <canvas/vclwrapper.hxx>
  27 #include "outdevprovider.hxx"
  28
  29 #include <boost/shared_ptr.hpp>
  30
  31
  32 namespace vclcanvas
  33 {
  34     /** Backbuffer implementation for canvas bitmap.
  35
  36         This class abstracts away the renderable bitmap for the bitmap
  37         canvas. The actual VirtualDevice is only created when
  38         necessary, which makes read-only bitmaps a lot smaller.
  39     */
  40     class BitmapBackBuffer : public OutDevProvider
  41     {
  42     public:
  43         /** Create a backbuffer for given reference device
  44          */
  45         BitmapBackBuffer( const BitmapEx&       rBitmap,
  46                           const OutputDevice&   rRefDevice );
  47
  48         virtual ~BitmapBackBuffer();
  49
  50         virtual OutputDevice&       getOutDev() SAL_OVERRIDE;
  51         virtual const OutputDevice& getOutDev() const SAL_OVERRIDE;
  52
  53         /// Clear the underlying bitmap to white, all transparent
  54         void clear();
  55
  56         /** Exposing our internal bitmap. Only to be used from
  57             CanvasBitmapHelper
  58
  59             @internal
  60         */
  61         BitmapEx&                   getBitmapReference();
  62         Size                        getBitmapSizePixel() const;
  63
  64     private:
  65         void createVDev() const;
  66         void updateVDev() const;
  67
  68         ::canvas::vcltools::VCLObject<BitmapEx> maBitmap;
  69         mutable VclPtr<VirtualDevice>           mpVDev; // created only on demand
  70
  71         const OutputDevice&                     mrRefDevice;
  72
  73         /** When true, the bitmap contains the last valid
  74             content. When false, and mbVDevContentIsCurrent is true,
  75             the VDev contains the last valid content (which must be
  76             copied back to the bitmap, when getBitmapReference() is
  77             called). When both are false, this object is just
  78             initialized.
  79          */
  80         mutable bool                            mbBitmapContentIsCurrent;
  81
  82         /** When true, and mpVDev is non-NULL, the VDev contains the
  83             last valid content. When false, and
  84             mbBitmapContentIsCurrent is true, the bitmap contains the
  85             last valid content. When both are false, this object is
  86             just initialized.
  87          */
  88         mutable bool                            mbVDevContentIsCurrent;
  89     };
  90
  91     typedef ::boost::shared_ptr< BitmapBackBuffer > BitmapBackBufferSharedPtr;
  92
  93 }
  94
  95 #endif // INCLUDED_CANVAS_SOURCE_VCL_BITMAPBACKBUFFER_HXX
  96
  97 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */