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 #include "wx/dynarray.h"
  22
  23 // internal utility used to store a frame in 8bit-per-pixel format
  24 class 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 //
  37 enum 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
  49 class WXDLLIMPEXP_CORE wxGIFDecoder : public wxAnimationDecoder
  50 {
  51 public:
  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
  90 private:
  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     wxDECLARE_NO_COPY_CLASS(wxGIFDecoder);
 106 };
 107
 108 #endif // wxUSE_STREAMS && wxUSE_GIF
 109
 110 #endif // _WX_GIFDECOD_H_