include/wx/animdecod.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/animdecod.h
   3 // Purpose:     wxAnimationDecoder
   4 // Author:      Francesco Montorsi
   5 // CVS-ID:      $Id$
   6 // Copyright:   (c) 2006 Francesco Montorsi
   7 // Licence:     wxWindows licence
   8 /////////////////////////////////////////////////////////////////////////////
   9
  10 #ifndef _WX_ANIMDECOD_H
  11 #define _WX_ANIMDECOD_H
  12
  13 #include "wx/defs.h"
  14
  15 #if wxUSE_STREAMS && wxUSE_GIF
  16
  17 #include "wx/stream.h"
  18 #include "wx/image.h"
  19
  20 /*
  21
  22  Differences between a wxAnimationDecoder and a wxImageHandler:
  23
  24  1) wxImageHandlers always load an input stream directly into a given wxImage
  25     object converting from the format-specific data representation to the
  26     wxImage native format (RGB24).
  27     wxAnimationDecoders always load an input stream using some optimized format
  28     to store it which is format-depedent. This allows to store a (possibly big)
  29     animation using a format which is a good compromise between required memory
  30     and time required to blit in on the screen.
  31
  32  2) wxAnimationDecoders contain the animation data in some internal var.
  33     That's why they derive from wxObjectRefData: they are data which can be shared.
  34
  35  3) wxAnimationDecoders can be used by a wxImageHandler to retrieve a frame
  36     in wxImage format; the viceversa cannot be done.
  37
  38  4) wxAnimationDecoders are decoders only, thus do not support save features.
  39
  40  5) wxAnimationDecoders are directly used by wxAnimation (generic implementation)
  41     as wxObjectRefData while they need to be 'wrapped' by a wxImageHandler for
  42     wxImage uses.
  43
  44 */
  45
  46
  47 // --------------------------------------------------------------------------
  48 // Constants
  49 // --------------------------------------------------------------------------
  50
  51 // NB: the values of these enum items are not casual but coincide with the
  52 //     GIF disposal codes. Do not change them !!
  53 enum wxAnimationDisposal
  54 {
  55     // No disposal specified. The decoder is not required to take any action.
  56     wxANIM_UNSPECIFIED = -1,
  57
  58     // Do not dispose. The graphic is to be left in place.
  59     wxANIM_DONOTREMOVE = 0,
  60
  61     // Restore to background color. The area used by the graphic must be
  62     // restored to the background color.
  63     wxANIM_TOBACKGROUND = 1,
  64
  65     // Restore to previous. The decoder is required to restore the area
  66     // overwritten by the graphic with what was there prior to rendering the graphic.
  67     wxANIM_TOPREVIOUS = 2
  68 };
  69
  70 enum wxAnimationType
  71 {
  72     wxANIMATION_TYPE_INVALID,
  73     wxANIMATION_TYPE_GIF,
  74     wxANIMATION_TYPE_ANI,
  75
  76     wxANIMATION_TYPE_ANY
  77 };
  78
  79
  80 // --------------------------------------------------------------------------
  81 // wxAnimationDecoder class
  82 // --------------------------------------------------------------------------
  83
  84 class WXDLLEXPORT wxAnimationDecoder : public wxObjectRefData
  85 {
  86 protected:
  87     wxSize m_szAnimation;
  88     size_t m_nFrames;
  89
  90     // this is the colour to use for the wxANIM_TOBACKGROUND disposal.
  91     // if not specified by the animation, it's set to wxNullColour
  92     wxColour m_background;
  93
  94 public:     // frame specific data getters
  95
  96     // not all frames may be of the same size; e.g. GIF allows to
  97     // specify that between two frames only a smaller portion of the
  98     // entire animation has changed.
  99     virtual wxSize GetFrameSize(size_t frame) const = 0;
 100
 101     // the position of this frame in case it's not as big as m_szAnimation
 102     // or wxPoint(0,0) otherwise.
 103     virtual wxPoint GetFramePosition(size_t frame) const = 0;
 104
 105     // what should be done after displaying this frame.
 106     virtual wxAnimationDisposal GetDisposalMethod(size_t frame) const = 0;
 107
 108     // the number of milliseconds this frame should be displayed.
 109     // if returns -1 then the frame must be displayed forever.
 110     virtual long GetDelay(size_t frame) const = 0;
 111
 112     // get global data
 113     wxSize GetAnimationSize() const { return m_szAnimation; }
 114     wxColour GetBackgroundColour() const { return m_background; }
 115     size_t GetFrameCount() const { return m_nFrames; }
 116
 117 public:
 118     wxAnimationDecoder()
 119     {
 120         m_background = wxNullColour;
 121         m_nFrames = 0;
 122     }
 123     ~wxAnimationDecoder() {}
 124
 125
 126     virtual bool Load( wxInputStream& stream ) = 0;
 127     virtual bool CanRead( wxInputStream& stream ) const = 0;
 128
 129     virtual wxAnimationDecoder *Clone() const = 0;
 130     virtual wxAnimationType GetType() const = 0;
 131
 132     // convert given frame to wxImage
 133     virtual bool ConvertToImage(size_t frame, wxImage *image) const = 0;
 134 };
 135
 136
 137 #endif  // wxUSE_STREAM && wxUSE_GIF
 138 #endif  // _WX_ANIMDECOD_H
 139