1 /////////////////////////////////////////////////////////////////////////////
2 // Name:        wx/animdecod.h
3 // Purpose:     wxAnimationDecoder
4 // Author:      Francesco Montorsi
5 // CVS-ID:      $Id: animdecod.h 49563 2007-10-31 20:46:21Z VZ $
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 WXDLLEXPORT wxAnimationDecoder : public wxObjectRefData
88 {
89 public:
wxAnimationDecoder()90     wxAnimationDecoder()
91     {
92         m_background = wxNullColour;
93         m_nFrames = 0;
94     }
~wxAnimationDecoder()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
GetAnimationSize()130     wxSize GetAnimationSize() const { return m_szAnimation; }
GetBackgroundColour()131     wxColour GetBackgroundColour() const { return m_background; }
GetFrameCount()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 
147