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 #ifdef __GNUG__
  15 #pragma interface "gifdecod.h"
  16 #endif
  17
  18 #include "wx/setup.h"
  19
  20 #if wxUSE_STREAMS && wxUSE_GIF
  21
  22 #include "wx/stream.h"
  23 #include "wx/image.h"
  24
  25
  26 // --------------------------------------------------------------------------
  27 // constants
  28 // --------------------------------------------------------------------------
  29
  30 // disposal method
  31 enum
  32 {
  33     wxGIF_D_UNSPECIFIED = -1,       /* not specified */
  34     wxGIF_D_DONOTDISPOSE = 0,       /* do not dispose */
  35     wxGIF_D_TOBACKGROUND = 1,       /* restore to background colour */
  36     wxGIF_D_TOPREVIOUS = 2          /* restore to previous image */
  37 };
  38
  39 // error codes
  40 enum
  41 {
  42     wxGIF_OK = 0,                   /* everything was OK */
  43     wxGIF_INVFORMAT = 1,            /* error in gif header */
  44     wxGIF_MEMERR = 2                /* error allocating memory */
  45 };
  46
  47 #define MAX_BLOCK_SIZE 256          /* max. block size */
  48
  49
  50 // --------------------------------------------------------------------------
  51 // wxGIFDecoder class
  52 // --------------------------------------------------------------------------
  53
  54 // internal class for storing GIF image data
  55 class GIFImage
  56 {
  57 public:
  58     unsigned int w;                 /* width */
  59     unsigned int h;                 /* height */
  60     unsigned int left;              /* x coord (in logical screen) */
  61     unsigned int top;               /* y coord (in logical screen) */
  62     int transparent;                /* transparent color (-1 = none) */
  63     int disposal;                   /* disposal method (-1 = unspecified) */
  64     long delay;                     /* delay in ms (-1 = unused) */
  65     unsigned char *p;               /* bitmap */
  66     unsigned char *pal;             /* palette */
  67     GIFImage *next;                 /* next image */
  68     GIFImage *prev;                 /* prev image */
  69 };
  70
  71
  72 class WXDLLEXPORT wxGIFDecoder
  73 {
  74 private:
  75     // logical screen
  76     unsigned int  m_screenw;        /* logical screen width */
  77     unsigned int  m_screenh;        /* logical screen height */
  78     int           m_background;     /* background color (-1 = none) */
  79
  80     // image data
  81     bool          m_anim;           /* animated GIF */
  82     int           m_nimages;        /* number of images */
  83     int           m_image;          /* current image */
  84     GIFImage      *m_pimage;        /* pointer to current image */
  85     GIFImage      *m_pfirst;        /* pointer to first image */
  86     GIFImage      *m_plast;         /* pointer to last image */
  87
  88     // decoder state vars
  89     int           m_restbits;       /* remaining valid bits */
  90     unsigned int  m_restbyte;       /* remaining bytes in this block */
  91     unsigned int  m_lastbyte;       /* last byte read */
  92     unsigned char m_buffer[MAX_BLOCK_SIZE];     /* buffer for reading */
  93     unsigned char *m_bufp;          /* pointer to next byte in buffer */
  94
  95     // input stream
  96     wxInputStream *m_f;             /* input stream */
  97
  98 private:
  99     int getcode(int bits, int abfin);
 100     int dgif(GIFImage *img, int interl, int bits);
 101
 102 protected:
 103     // get data of current frame
 104     int GetFrameIndex() const;
 105     unsigned char* GetData() const;
 106     unsigned char* GetPalette() const;
 107     unsigned int GetWidth() const;
 108     unsigned int GetHeight() const;
 109     unsigned int GetLeft() const;
 110     unsigned int GetTop() const;
 111     int GetDisposalMethod() const;
 112     int GetTransparentColour() const;
 113     long GetDelay() const;
 114
 115     // get global data
 116     unsigned int GetLogicalScreenWidth() const;
 117     unsigned int GetLogicalScreenHeight() const;
 118     int GetBackgroundColour() const;
 119     int GetNumberOfFrames() const;
 120     bool IsAnimation() const;
 121
 122     // move through the animation
 123     bool GoFirstFrame();
 124     bool GoLastFrame();
 125     bool GoNextFrame(bool cyclic = FALSE);
 126     bool GoPrevFrame(bool cyclic = FALSE);
 127     bool GoFrame(int which);
 128
 129 public:
 130     // constructor, destructor, etc.
 131     wxGIFDecoder(wxInputStream *s, bool anim = FALSE);
 132     ~wxGIFDecoder();
 133     bool CanRead();
 134     int ReadGIF();
 135     void Destroy();
 136
 137     // convert current frame to wxImage
 138     bool ConvertToImage(wxImage *image) const;
 139 };
 140
 141
 142 #endif  // wxUSE_STREAM && wxUSE_GIF
 143 #endif  // _WX_GIFDECOD_H
 144