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 #if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
  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 // 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. the
  35 //
  36 enum
  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 // Disposal method
  45 //  Experimental; subject to change.
  46 //
  47 enum
  48 {
  49     wxGIF_D_UNSPECIFIED = -1,       /* not specified */
  50     wxGIF_D_DONOTDISPOSE = 0,       /* do not dispose */
  51     wxGIF_D_TOBACKGROUND = 1,       /* restore to background colour */
  52     wxGIF_D_TOPREVIOUS = 2          /* restore to previous image */
  53 };
  54
  55
  56 #define MAX_BLOCK_SIZE 256          /* max. block size */
  57
  58
  59 // --------------------------------------------------------------------------
  60 // wxGIFDecoder class
  61 // --------------------------------------------------------------------------
  62
  63 // internal class for storing GIF image data
  64 class GIFImage
  65 {
  66 public:
  67     // def ctor
  68     GIFImage();
  69
  70     unsigned int w;                 /* width */
  71     unsigned int h;                 /* height */
  72     unsigned int left;              /* x coord (in logical screen) */
  73     unsigned int top;               /* y coord (in logical screen) */
  74     int transparent;                /* transparent color (-1 = none) */
  75     int disposal;                   /* disposal method (-1 = unspecified) */
  76     long delay;                     /* delay in ms (-1 = unused) */
  77     unsigned char *p;               /* bitmap */
  78     unsigned char *pal;             /* palette */
  79     GIFImage *next;                 /* next image */
  80     GIFImage *prev;                 /* prev image */
  81
  82     DECLARE_NO_COPY_CLASS(GIFImage)
  83 };
  84
  85
  86 class WXDLLEXPORT wxGIFDecoder
  87 {
  88 private:
  89     // logical screen
  90     unsigned int  m_screenw;        /* logical screen width */
  91     unsigned int  m_screenh;        /* logical screen height */
  92     int           m_background;     /* background color (-1 = none) */
  93
  94     // image data
  95     bool          m_anim;           /* animated GIF */
  96     int           m_nimages;        /* number of images */
  97     int           m_image;          /* current image */
  98     GIFImage      *m_pimage;        /* pointer to current image */
  99     GIFImage      *m_pfirst;        /* pointer to first image */
 100     GIFImage      *m_plast;         /* pointer to last image */
 101
 102     // decoder state vars
 103     int           m_restbits;       /* remaining valid bits */
 104     unsigned int  m_restbyte;       /* remaining bytes in this block */
 105     unsigned int  m_lastbyte;       /* last byte read */
 106     unsigned char m_buffer[MAX_BLOCK_SIZE];     /* buffer for reading */
 107     unsigned char *m_bufp;          /* pointer to next byte in buffer */
 108
 109     // input stream
 110     wxInputStream *m_f;             /* input stream */
 111
 112 private:
 113     int getcode(int bits, int abfin);
 114     int dgif(GIFImage *img, int interl, int bits);
 115
 116 public:
 117     // get data of current frame
 118     int GetFrameIndex() const;
 119     unsigned char* GetData() const;
 120     unsigned char* GetPalette() const;
 121     unsigned int GetWidth() const;
 122     unsigned int GetHeight() const;
 123     unsigned int GetLeft() const;
 124     unsigned int GetTop() const;
 125     int GetDisposalMethod() const;
 126     int GetTransparentColour() const;
 127     long GetDelay() const;
 128
 129     // get global data
 130     unsigned int GetLogicalScreenWidth() const;
 131     unsigned int GetLogicalScreenHeight() const;
 132     int GetBackgroundColour() const;
 133     int GetNumberOfFrames() const;
 134     bool IsAnimation() const;
 135
 136     // move through the animation
 137     bool GoFirstFrame();
 138     bool GoLastFrame();
 139     bool GoNextFrame(bool cyclic = FALSE);
 140     bool GoPrevFrame(bool cyclic = FALSE);
 141     bool GoFrame(int which);
 142
 143 public:
 144     // constructor, destructor, etc.
 145     wxGIFDecoder(wxInputStream *s, bool anim = FALSE);
 146     ~wxGIFDecoder();
 147     bool CanRead();
 148     int ReadGIF();
 149     void Destroy();
 150
 151     // convert current frame to wxImage
 152     bool ConvertToImage(wxImage *image) const;
 153
 154     DECLARE_NO_COPY_CLASS(wxGIFDecoder)
 155 };
 156
 157
 158 #endif  // wxUSE_STREAM && wxUSE_GIF
 159 #endif  // _WX_GIFDECOD_H
 160