include/wx/gifdecod.h

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