wxWidgets/include/wx/gifdecod.h
2003-01-02 23:38:11 +00:00

161 lines
5.0 KiB
C++

/////////////////////////////////////////////////////////////////////////////
// Name: gifdecod.h
// Purpose: wxGIFDecoder, GIF reader for wxImage and wxAnimation
// Author: Guillermo Rodriguez Garcia <guille@iies.es>
// Version: 3.02
// CVS-ID: $Id$
// Copyright: (c) 1999 Guillermo Rodriguez Garcia
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
#ifndef _WX_GIFDECOD_H
#define _WX_GIFDECOD_H
#if defined(__GNUG__) && !defined(__APPLE__)
#pragma interface "gifdecod.h"
#endif
#include "wx/setup.h"
#if wxUSE_STREAMS && wxUSE_GIF
#include "wx/stream.h"
#include "wx/image.h"
// --------------------------------------------------------------------------
// Constants
// --------------------------------------------------------------------------
// Error codes:
// Note that the error code wxGIF_TRUNCATED means that the image itself
// is most probably OK, but the decoder didn't reach the end of the data
// stream; this means that if it was not reading directly from file,
// the stream will not be correctly positioned. the
//
enum
{
wxGIF_OK = 0, /* everything was OK */
wxGIF_INVFORMAT, /* error in gif header */
wxGIF_MEMERR, /* error allocating memory */
wxGIF_TRUNCATED /* file appears to be truncated */
};
// Disposal method
// Experimental; subject to change.
//
enum
{
wxGIF_D_UNSPECIFIED = -1, /* not specified */
wxGIF_D_DONOTDISPOSE = 0, /* do not dispose */
wxGIF_D_TOBACKGROUND = 1, /* restore to background colour */
wxGIF_D_TOPREVIOUS = 2 /* restore to previous image */
};
#define MAX_BLOCK_SIZE 256 /* max. block size */
// --------------------------------------------------------------------------
// wxGIFDecoder class
// --------------------------------------------------------------------------
// internal class for storing GIF image data
class GIFImage
{
public:
// def ctor
GIFImage();
unsigned int w; /* width */
unsigned int h; /* height */
unsigned int left; /* x coord (in logical screen) */
unsigned int top; /* y coord (in logical screen) */
int transparent; /* transparent color (-1 = none) */
int disposal; /* disposal method (-1 = unspecified) */
long delay; /* delay in ms (-1 = unused) */
unsigned char *p; /* bitmap */
unsigned char *pal; /* palette */
GIFImage *next; /* next image */
GIFImage *prev; /* prev image */
DECLARE_NO_COPY_CLASS(GIFImage)
};
class WXDLLEXPORT wxGIFDecoder
{
private:
// logical screen
unsigned int m_screenw; /* logical screen width */
unsigned int m_screenh; /* logical screen height */
int m_background; /* background color (-1 = none) */
// image data
bool m_anim; /* animated GIF */
int m_nimages; /* number of images */
int m_image; /* current image */
GIFImage *m_pimage; /* pointer to current image */
GIFImage *m_pfirst; /* pointer to first image */
GIFImage *m_plast; /* pointer to last image */
// decoder state vars
int m_restbits; /* remaining valid bits */
unsigned int m_restbyte; /* remaining bytes in this block */
unsigned int m_lastbyte; /* last byte read */
unsigned char m_buffer[MAX_BLOCK_SIZE]; /* buffer for reading */
unsigned char *m_bufp; /* pointer to next byte in buffer */
// input stream
wxInputStream *m_f; /* input stream */
private:
int getcode(int bits, int abfin);
int dgif(GIFImage *img, int interl, int bits);
public:
// get data of current frame
int GetFrameIndex() const;
unsigned char* GetData() const;
unsigned char* GetPalette() const;
unsigned int GetWidth() const;
unsigned int GetHeight() const;
unsigned int GetLeft() const;
unsigned int GetTop() const;
int GetDisposalMethod() const;
int GetTransparentColour() const;
long GetDelay() const;
// get global data
unsigned int GetLogicalScreenWidth() const;
unsigned int GetLogicalScreenHeight() const;
int GetBackgroundColour() const;
int GetNumberOfFrames() const;
bool IsAnimation() const;
// move through the animation
bool GoFirstFrame();
bool GoLastFrame();
bool GoNextFrame(bool cyclic = FALSE);
bool GoPrevFrame(bool cyclic = FALSE);
bool GoFrame(int which);
public:
// constructor, destructor, etc.
wxGIFDecoder(wxInputStream *s, bool anim = FALSE);
~wxGIFDecoder();
bool CanRead();
int ReadGIF();
void Destroy();
// convert current frame to wxImage
bool ConvertToImage(wxImage *image) const;
DECLARE_NO_COPY_CLASS(wxGIFDecoder)
};
#endif // wxUSE_STREAM && wxUSE_GIF
#endif // _WX_GIFDECOD_H