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_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 public:
  90     wxAnimationDecoder()
  91     {
  92         m_background = wxNullColour;
  93         m_nFrames = 0;
  94     }
  95     virtual ~wxAnimationDecoder() { }
  96
  97
  98     virtual bool Load( wxInputStream& stream ) = 0;
  99     virtual bool CanRead( wxInputStream& stream ) const = 0;
 100
 101     virtual wxAnimationDecoder *Clone() const = 0;
 102     virtual wxAnimationType GetType() const = 0;
 103
 104     // convert given frame to wxImage
 105     virtual bool ConvertToImage(unsigned int frame, wxImage *image) const = 0;
 106
 107
 108     // frame specific data getters
 109
 110     // not all frames may be of the same size; e.g. GIF allows to
 111     // specify that between two frames only a smaller portion of the
 112     // entire animation has changed.
 113     virtual wxSize GetFrameSize(unsigned int frame) const = 0;
 114
 115     // the position of this frame in case it's not as big as m_szAnimation
 116     // or wxPoint(0,0) otherwise.
 117     virtual wxPoint GetFramePosition(unsigned int frame) const = 0;
 118
 119     // what should be done after displaying this frame.
 120     virtual wxAnimationDisposal GetDisposalMethod(unsigned int frame) const = 0;
 121
 122     // the number of milliseconds this frame should be displayed.
 123     // if returns -1 then the frame must be displayed forever.
 124     virtual long GetDelay(unsigned int frame) const = 0;
 125
 126     // the transparent colour for this frame if any or wxNullColour.
 127     virtual wxColour GetTransparentColour(unsigned int frame) const = 0;
 128
 129     // get global data
 130     wxSize GetAnimationSize() const { return m_szAnimation; }
 131     wxColour GetBackgroundColour() const { return m_background; }
 132     unsigned int GetFrameCount() const { return m_nFrames; }
 133
 134 protected:
 135     wxSize m_szAnimation;
 136     unsigned int m_nFrames;
 137
 138     // this is the colour to use for the wxANIM_TOBACKGROUND disposal.
 139     // if not specified by the animation, it's set to wxNullColour
 140     wxColour m_background;
 141 };
 142
 143
 144 #endif  // wxUSE_STREAM
 145 #endif  // _WX_ANIMDECOD_H
 146