1/////////////////////////////////////////////////////////////////////////////
2// Name:        wx/gifdecod.h
3// Purpose:     wxGIFDecoder, GIF reader for wxImage and wxAnimation
4// Author:      Guillermo Rodriguez Garcia <guille@iies.es>
5// Version:     3.02
6// CVS-ID:      $Id: gifdecod.h 45563 2007-04-21 18:17:50Z VZ $
7// Copyright:   (c) 1999 Guillermo Rodriguez Garcia
8// Licence:     wxWindows licence
9/////////////////////////////////////////////////////////////////////////////
10
11#ifndef _WX_GIFDECOD_H_
12#define _WX_GIFDECOD_H_
13
14#include "wx/defs.h"
15
16#if wxUSE_STREAMS && wxUSE_GIF
17
18#include "wx/stream.h"
19#include "wx/image.h"
20#include "wx/animdecod.h"
21#include "wx/dynarray.h"
22
23// internal utility used to store a frame in 8bit-per-pixel format
24class GIFImage;
25
26
27// --------------------------------------------------------------------------
28// Constants
29// --------------------------------------------------------------------------
30
31// Error codes:
32//  Note that the error code wxGIF_TRUNCATED means that the image itself
33//  is most probably OK, but the decoder didn't reach the end of the data
34//  stream; this means that if it was not reading directly from file,
35//  the stream will not be correctly positioned.
36//
37enum wxGIFErrorCode
38{
39    wxGIF_OK = 0,                   // everything was OK
40    wxGIF_INVFORMAT,                // error in GIF header
41    wxGIF_MEMERR,                   // error allocating memory
42    wxGIF_TRUNCATED                 // file appears to be truncated
43};
44
45// --------------------------------------------------------------------------
46// wxGIFDecoder class
47// --------------------------------------------------------------------------
48
49class WXDLLEXPORT wxGIFDecoder : public wxAnimationDecoder
50{
51public:
52    // constructor, destructor, etc.
53    wxGIFDecoder();
54    ~wxGIFDecoder();
55
56    // get data of current frame
57    unsigned char* GetData(unsigned int frame) const;
58    unsigned char* GetPalette(unsigned int frame) const;
59    unsigned int GetNcolours(unsigned int frame) const;
60    int GetTransparentColourIndex(unsigned int frame) const;
61    wxColour GetTransparentColour(unsigned int frame) const;
62
63    virtual wxSize GetFrameSize(unsigned int frame) const;
64    virtual wxPoint GetFramePosition(unsigned int frame) const;
65    virtual wxAnimationDisposal GetDisposalMethod(unsigned int frame) const;
66    virtual long GetDelay(unsigned int frame) const;
67
68    // GIFs can contain both static images and animations
69    bool IsAnimation() const
70        { return m_nFrames > 1; }
71
72    // load function which returns more info than just Load():
73    wxGIFErrorCode LoadGIF( wxInputStream& stream );
74
75    // free all internal frames
76    void Destroy();
77
78    // implementation of wxAnimationDecoder's pure virtuals
79    virtual bool CanRead( wxInputStream& stream ) const;
80    virtual bool Load( wxInputStream& stream )
81        { return LoadGIF(stream) == wxGIF_OK; }
82
83    bool ConvertToImage(unsigned int frame, wxImage *image) const;
84
85    wxAnimationDecoder *Clone() const
86        { return new wxGIFDecoder; }
87    wxAnimationType GetType() const
88        { return wxANIMATION_TYPE_GIF; }
89
90private:
91    // array of all frames
92    wxArrayPtrVoid m_frames;
93
94    // decoder state vars
95    int           m_restbits;       // remaining valid bits
96    unsigned int  m_restbyte;       // remaining bytes in this block
97    unsigned int  m_lastbyte;       // last byte read
98    unsigned char m_buffer[256];    // buffer for reading
99    unsigned char *m_bufp;          // pointer to next byte in buffer
100
101    int getcode(wxInputStream& stream, int bits, int abfin);
102    wxGIFErrorCode dgif(wxInputStream& stream,
103                        GIFImage *img, int interl, int bits);
104
105    DECLARE_NO_COPY_CLASS(wxGIFDecoder)
106};
107
108#endif // wxUSE_STREAM && wxUSE_GIF
109
110#endif // _WX_GIFDECOD_H_
111