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/colour.h"
  18 #include "wx/gdicmn.h"
  19
  20 class WXDLLIMPEXP_BASE wxInputStream;
  21 class WXDLLIMPEXP_CORE wxImage;
  22
  23 /*
  24
  25  Differences between a wxAnimationDecoder and a wxImageHandler:
  26
  27  1) wxImageHandlers always load an input stream directly into a given wxImage
  28     object converting from the format-specific data representation to the
  29     wxImage native format (RGB24).
  30     wxAnimationDecoders always load an input stream using some optimized format
  31     to store it which is format-depedent. This allows to store a (possibly big)
  32     animation using a format which is a good compromise between required memory
  33     and time required to blit in on the screen.
  34
  35  2) wxAnimationDecoders contain the animation data in some internal var.
  36     That's why they derive from wxObjectRefData: they are data which can be shared.
  37
  38  3) wxAnimationDecoders can be used by a wxImageHandler to retrieve a frame
  39     in wxImage format; the viceversa cannot be done.
  40
  41  4) wxAnimationDecoders are decoders only, thus do not support save features.
  42
  43  5) wxAnimationDecoders are directly used by wxAnimation (generic implementation)
  44     as wxObjectRefData while they need to be 'wrapped' by a wxImageHandler for
  45     wxImage uses.
  46
  47 */
  48
  49
  50 // --------------------------------------------------------------------------
  51 // Constants
  52 // --------------------------------------------------------------------------
  53
  54 // NB: the values of these enum items are not casual but coincide with the
  55 //     GIF disposal codes. Do not change them !!
  56 enum wxAnimationDisposal
  57 {
  58     // No disposal specified. The decoder is not required to take any action.
  59     wxANIM_UNSPECIFIED = -1,
  60
  61     // Do not dispose. The graphic is to be left in place.
  62     wxANIM_DONOTREMOVE = 0,
  63
  64     // Restore to background color. The area used by the graphic must be
  65     // restored to the background color.
  66     wxANIM_TOBACKGROUND = 1,
  67
  68     // Restore to previous. The decoder is required to restore the area
  69     // overwritten by the graphic with what was there prior to rendering the graphic.
  70     wxANIM_TOPREVIOUS = 2
  71 };
  72
  73 enum wxAnimationType
  74 {
  75     wxANIMATION_TYPE_INVALID,
  76     wxANIMATION_TYPE_GIF,
  77     wxANIMATION_TYPE_ANI,
  78
  79     wxANIMATION_TYPE_ANY
  80 };
  81
  82
  83 // --------------------------------------------------------------------------
  84 // wxAnimationDecoder class
  85 // --------------------------------------------------------------------------
  86
  87 class WXDLLEXPORT wxAnimationDecoder : public wxObjectRefData
  88 {
  89 protected:
  90     wxSize m_szAnimation;
  91     size_t m_nFrames;
  92
  93     // this is the colour to use for the wxANIM_TOBACKGROUND disposal.
  94     // if not specified by the animation, it's set to wxNullColour
  95     wxColour m_background;
  96
  97 public:     // frame specific data getters
  98
  99     // not all frames may be of the same size; e.g. GIF allows to
 100     // specify that between two frames only a smaller portion of the
 101     // entire animation has changed.
 102     virtual wxSize GetFrameSize(size_t frame) const = 0;
 103
 104     // the position of this frame in case it's not as big as m_szAnimation
 105     // or wxPoint(0,0) otherwise.
 106     virtual wxPoint GetFramePosition(size_t frame) const = 0;
 107
 108     // what should be done after displaying this frame.
 109     virtual wxAnimationDisposal GetDisposalMethod(size_t frame) const = 0;
 110
 111     // the number of milliseconds this frame should be displayed.
 112     // if returns -1 then the frame must be displayed forever.
 113     virtual long GetDelay(size_t frame) const = 0;
 114
 115     // the transparent colour for this frame if any or wxNullColour.
 116     virtual wxColour GetTransparentColour(size_t frame) const = 0;
 117
 118     // get global data
 119     wxSize GetAnimationSize() const { return m_szAnimation; }
 120     wxColour GetBackgroundColour() const { return m_background; }
 121     size_t GetFrameCount() const { return m_nFrames; }
 122
 123 public:
 124     wxAnimationDecoder()
 125     {
 126         m_background = wxNullColour;
 127         m_nFrames = 0;
 128     }
 129     ~wxAnimationDecoder() {}
 130
 131
 132     virtual bool Load( wxInputStream& stream ) = 0;
 133     virtual bool CanRead( wxInputStream& stream ) const = 0;
 134
 135     virtual wxAnimationDecoder *Clone() const = 0;
 136     virtual wxAnimationType GetType() const = 0;
 137
 138     // convert given frame to wxImage
 139     virtual bool ConvertToImage(size_t frame, wxImage *image) const = 0;
 140 };
 141
 142
 143 #endif  // wxUSE_STREAM && wxUSE_GIF
 144 #endif  // _WX_ANIMDECOD_H
 145