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
  16
  17 #include "wx/colour.h"
  18 #include "wx/gdicmn.h"
  19
  20 class WXDLLIMPEXP_FWD_BASE wxInputStream;
  21 class WXDLLIMPEXP_FWD_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 WXDLLIMPEXP_CORE wxAnimationDecoder : public wxObjectRefData
  88 {
  89 public:
  90     wxAnimationDecoder()
  91     {
  92         m_nFrames = 0;
  93     }
  94
  95     virtual bool Load( wxInputStream& stream ) = 0;
  96     virtual bool CanRead( wxInputStream& stream ) const = 0;
  97
  98     virtual wxAnimationDecoder *Clone() const = 0;
  99     virtual wxAnimationType GetType() const = 0;
 100
 101     // convert given frame to wxImage
 102     virtual bool ConvertToImage(unsigned int frame, wxImage *image) const = 0;
 103
 104
 105     // frame specific data getters
 106
 107     // not all frames may be of the same size; e.g. GIF allows to
 108     // specify that between two frames only a smaller portion of the
 109     // entire animation has changed.
 110     virtual wxSize GetFrameSize(unsigned int frame) const = 0;
 111
 112     // the position of this frame in case it's not as big as m_szAnimation
 113     // or wxPoint(0,0) otherwise.
 114     virtual wxPoint GetFramePosition(unsigned int frame) const = 0;
 115
 116     // what should be done after displaying this frame.
 117     virtual wxAnimationDisposal GetDisposalMethod(unsigned int frame) const = 0;
 118
 119     // the number of milliseconds this frame should be displayed.
 120     // if returns -1 then the frame must be displayed forever.
 121     virtual long GetDelay(unsigned int frame) const = 0;
 122
 123     // the transparent colour for this frame if any or wxNullColour.
 124     virtual wxColour GetTransparentColour(unsigned int frame) const = 0;
 125
 126     // get global data
 127     wxSize GetAnimationSize() const { return m_szAnimation; }
 128     wxColour GetBackgroundColour() const { return m_background; }
 129     unsigned int GetFrameCount() const { return m_nFrames; }
 130
 131 protected:
 132     wxSize m_szAnimation;
 133     unsigned int m_nFrames;
 134
 135     // this is the colour to use for the wxANIM_TOBACKGROUND disposal.
 136     // if not specified by the animation, it's set to wxNullColour
 137     wxColour m_background;
 138 };
 139
 140 #endif  // wxUSE_STREAMS
 141
 142 #endif  // _WX_ANIMDECOD_H
 143