include/wx/gifdecod.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        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
  21
  22 // --------------------------------------------------------------------------
  23 // Constants
  24 // --------------------------------------------------------------------------
  25
  26 // Error codes:
  27 //  Note that the error code wxGIF_TRUNCATED means that the image itself
  28 //  is most probably OK, but the decoder didn't reach the end of the data
  29 //  stream; this means that if it was not reading directly from file,
  30 //  the stream will not be correctly positioned. the
  31 //
  32 enum
  33 {
  34     wxGIF_OK = 0,                   /* everything was OK */
  35     wxGIF_INVFORMAT,                /* error in gif header */
  36     wxGIF_MEMERR,                   /* error allocating memory */
  37     wxGIF_TRUNCATED                 /* file appears to be truncated */
  38 };
  39
  40 // Disposal method
  41 //  Experimental; subject to change.
  42 //
  43 enum
  44 {
  45     wxGIF_D_UNSPECIFIED = -1,       /* not specified */
  46     wxGIF_D_DONOTDISPOSE = 0,       /* do not dispose */
  47     wxGIF_D_TOBACKGROUND = 1,       /* restore to background colour */
  48     wxGIF_D_TOPREVIOUS = 2          /* restore to previous image */
  49 };
  50
  51
  52 #define MAX_BLOCK_SIZE 256          /* max. block size */
  53
  54
  55 // --------------------------------------------------------------------------
  56 // wxGIFDecoder class
  57 // --------------------------------------------------------------------------
  58
  59 // internal class for storing GIF image data
  60 class GIFImage
  61 {
  62 public:
  63     // def ctor
  64     GIFImage();
  65
  66     unsigned int w;                 /* width */
  67     unsigned int h;                 /* height */
  68     unsigned int left;              /* x coord (in logical screen) */
  69     unsigned int top;               /* y coord (in logical screen) */
  70     int transparent;                /* transparent color (-1 = none) */
  71     int disposal;                   /* disposal method (-1 = unspecified) */
  72     long delay;                     /* delay in ms (-1 = unused) */
  73     unsigned char *p;               /* bitmap */
  74     unsigned char *pal;             /* palette */
  75     unsigned int ncolours;          /* number of colours */
  76     GIFImage *next;                 /* next image */
  77     GIFImage *prev;                 /* prev image */
  78
  79     DECLARE_NO_COPY_CLASS(GIFImage)
  80 };
  81
  82
  83 class WXDLLEXPORT wxGIFDecoder
  84 {
  85 private:
  86     // logical screen
  87     unsigned int  m_screenw;        /* logical screen width */
  88     unsigned int  m_screenh;        /* logical screen height */
  89     int           m_background;     /* background color (-1 = none) */
  90
  91     // image data
  92     bool          m_anim;           /* animated GIF */
  93     int           m_nimages;        /* number of images */
  94     int           m_image;          /* current image */
  95     GIFImage      *m_pimage;        /* pointer to current image */
  96     GIFImage      *m_pfirst;        /* pointer to first image */
  97     GIFImage      *m_plast;         /* pointer to last image */
  98
  99     // decoder state vars
 100     int           m_restbits;       /* remaining valid bits */
 101     unsigned int  m_restbyte;       /* remaining bytes in this block */
 102     unsigned int  m_lastbyte;       /* last byte read */
 103     unsigned char m_buffer[MAX_BLOCK_SIZE];     /* buffer for reading */
 104     unsigned char *m_bufp;          /* pointer to next byte in buffer */
 105
 106     // input stream
 107     wxInputStream *m_f;             /* input stream */
 108
 109 private:
 110     int getcode(int bits, int abfin);
 111     int dgif(GIFImage *img, int interl, int bits);
 112
 113 public:
 114     // get data of current frame
 115     int GetFrameIndex() const;
 116     unsigned char* GetData() const;
 117     unsigned char* GetPalette() const;
 118     unsigned int GetNcolours() const;
 119     unsigned int GetWidth() const;
 120     unsigned int GetHeight() const;
 121     unsigned int GetLeft() const;
 122     unsigned int GetTop() const;
 123     int GetDisposalMethod() const;
 124     int GetTransparentColour() const;
 125     long GetDelay() const;
 126
 127     // get global data
 128     unsigned int GetLogicalScreenWidth() const;
 129     unsigned int GetLogicalScreenHeight() const;
 130     int GetBackgroundColour() const;
 131     int GetNumberOfFrames() const;
 132     bool IsAnimation() const;
 133
 134     // move through the animation
 135     bool GoFirstFrame();
 136     bool GoLastFrame();
 137     bool GoNextFrame(bool cyclic = false);
 138     bool GoPrevFrame(bool cyclic = false);
 139     bool GoFrame(int which);
 140
 141 public:
 142     // constructor, destructor, etc.
 143     wxGIFDecoder(wxInputStream *s, bool anim = false);
 144     ~wxGIFDecoder();
 145     bool CanRead();
 146     int ReadGIF();
 147     void Destroy();
 148
 149     // convert current frame to wxImage
 150     bool ConvertToImage(wxImage *image) const;
 151
 152     DECLARE_NO_COPY_CLASS(wxGIFDecoder)
 153 };
 154
 155
 156 #endif  // wxUSE_STREAM && wxUSE_GIF
 157 #endif  // _WX_GIFDECOD_H
 158