-#include <wx/wx.h>
-
-#include <wx/image.h>
-#include <wx/wfstream.h>
-#include <wx/module.h>
-
-#include <wx/imaggif.h>
-
-/*
-
-FOLLOWING CODE IS BY G.R.G. :
-(except wxInputStream stuff)
-
-*/
-
-/************************************************************************
- READGIF.H - Reads a GIF file
- ------------------------------------------------------------------------
- Guillermo Rodriguez Garcia
- <guille@iies.es>
-
- Version: 2.1
-*************************************************************************/
-
-
-typedef struct
-{
- int w; /* width */
- int h; /* height */
- int transparent; /* transparent color (-1 = none) */
- unsigned char *p; /* bitmap */
- unsigned char *pal; /* palette */
-} IMAGEN;
-
-
-
-/************************************************************************
- READGIF.C - Reads a GIF file
- ------------------------------------------------------------------------
- Guillermo Rodriguez Garcia
- <guille@iies.es>
-
- Version: 2.1
-*************************************************************************/
-
-
-#include <stdlib.h>
-#include <string.h>
-
-
-/* error codes */
-#define E_OK 0 /* everything was OK */
-#define E_ARCHIVO -1 /* error opening file */
-#define E_FORMATO -2 /* error in gif header */
-#define E_MEMORIA -3 /* error allocating memory */
-
-
-/* This class binding is by VS, so all bugs in it are mine ;-) */
-
-class gifDecoder
-{
- private:
- /* globals */
- int restbits; /* remaining valid bits */
- unsigned int restbyte; /* remaining bytes in this block */
- unsigned int lastbyte; /* last byte read */
-
- wxInputStream *f; /* input file */
-
- public:
- gifDecoder(wxInputStream *s) { f = s; }
- int getcode(int bits);
- int dgif(IMAGEN *img, int interl, int bits);
- int readgif(IMAGEN *img);
-};
-
-
-
-/* getcode:
- * Reads the next code from the file, with size 'bits'
- */
-int gifDecoder::getcode(int bits)
-{
- unsigned int mask; /* bit mask */
- unsigned int code; /* code (result) */
-
-
- /* get remaining bits from last byte read */
- mask = (1 << bits) - 1;
- code = (lastbyte >> (8 - restbits)) & mask;
-
- /* keep reading new bytes while needed */
- while (bits > restbits)
- {
- /* if no bytes left in this block, read the next block */
- if (restbyte == 0)
- restbyte = (unsigned char)f->GetC();
-
- /* read next byte and isolate the bits we need */
- lastbyte = (unsigned char)f->GetC();
- mask = (1 << (bits - restbits)) - 1;
- code = code + ((lastbyte & mask) << restbits);
- restbyte--;
-
- /* adjust total number of bits extracted from the buffer */
- restbits = restbits + 8;
- }
-
- /* find number of bits reamining for next code */
- restbits = (restbits - bits);
-
- return code;
-}
-
-
-
-/* dgif:
- * GIF decoding function. The initial code size (aka root size)
- * is 'bits'. Supports interlaced images (interl == 1).
- */
-int gifDecoder::dgif(IMAGEN *img, int interl, int bits)
-{
- int ab_prefix[4096]; /* alphabet (prefixes) */
- int ab_tail[4096]; /* alphabet (tails) */
- int stack[4096]; /* decompression stack */
-
- int ab_clr; /* clear code */
- int ab_fin; /* end of info code */
- int ab_bits; /* actual symbol width, in bits */
- int ab_free; /* first free position in alphabet */
- int ab_max; /* last possible character in alphabet */
- int pass; /* pass number in interlaced images */
- int pos; /* index into decompresion stack */
- int x, y; /* position in image buffer */
-
- int code, readcode, lastcode, abcabca;
-
- /* these won't change */
- ab_clr = (1 << bits);
- ab_fin = (1 << bits) + 1;
-
- /* these will change through the decompression proccess */
- ab_bits = bits + 1;
- ab_free = (1 << bits) + 2;
- ab_max = (1 << ab_bits) - 1;
- lastcode = -1;
- abcabca = -1;
- pass = 1;
- pos = x = y = 0;
-
- /* reset static globals */
- restbits = 0;
- restbyte = 0;
- lastbyte = 0;
-
- do
- {
- /* get next code */
- readcode = code = getcode(ab_bits);
-
- /* end of image? */
- if (code == ab_fin) break;
-
- /* reset alphabet? */
- if (code == ab_clr)
- {
- /* reset main variables */
- ab_bits = bits + 1;
- ab_free = (1 << bits) + 2;
- ab_max = (1 << ab_bits) - 1;
- lastcode = -1;
- abcabca = -1;
-
- /* skip to next code */
- continue;
- }
-
- /* unknown code: special case (like in ABCABCA) */
- if (code >= ab_free)
- {
- code = lastcode; /* take last string */
- stack[pos++] = abcabca; /* add first character */
- }
-
- /* build the string for this code in the stack */
- while (code > ab_clr)
- {
- stack[pos++] = ab_tail[code];
- code = ab_prefix[code];
- }
- stack[pos] = code; /* push last code into the stack */
- abcabca = code; /* save for special case */
-
- /* make new entry in alphabet (only if NOT just cleared) */
- if (lastcode != -1)
- {
- ab_prefix[ab_free] = lastcode;
- ab_tail[ab_free] = code;
- ab_free++;
-
- if ((ab_free > ab_max) && (ab_bits < 12))
- {
- ab_bits++;
- ab_max = (1 << ab_bits) - 1;
- }
- }
-
- /* dump stack data to the buffer */
- while (pos >= 0)
- {
- (img->p)[x + (y * (img->w))] = (char)stack[pos--];
-
- if (++x >= (img->w))
- {
- x = 0;
-
- if (interl)
- {
- /* support for interlaced images */
- switch (pass)
- {
- case 1: y += 8; break;
- case 2: y += 8; break;
- case 3: y += 4; break;
- case 4: y += 2; break;
- }
- if (y >= (img->h))
- {
- switch (++pass)
- {
- case 2: y = 4; break;
- case 3: y = 2; break;
- case 4: y = 1; break;
- }
- }
- }
- else
- {
- /* non-interlaced */
- y++;
- }
- }
- }
-
- pos = 0;
- lastcode = readcode;
- }
- while (code != ab_fin);
-
- return 0;
-}
-
-
-
-/* readgif:
- * Reads a GIF image from the file with filename 'nombre' in the
- * IMAGEN structure pointed by 'img'. Can read GIFs with any bit
- * size (color depth), but the output image is always expanded
- * to 8 bits per pixel. Also, the image palette always contains
- * 256 colors, although some of them may be unused. Returns E_OK
- * (== 0) on success, or an error code if something fails. Error
- * codes are E_ARCHIVO, E_FORMATO, E_MEMORIA (see above).
- */
-int gifDecoder::readgif(IMAGEN *img)
-{
- int size, ncolors, bits, interl, i;
- unsigned char pal[768];
- unsigned char buf[16];
-
-
- /* read header and logical screen descriptor block (LSDB) */
- f->Read(buf, 13);
-
- /* check GIF signature */
- if (memcmp(buf, "GIF", 3) != 0) return E_FORMATO;
-
- /* load global color map if available */
- if ((buf[10] & 0x80) == 0x80)
- {
- ncolors = 2 << (buf[10] & 0x07);
- f->Read(pal, 3 * ncolors);
- }
-
- /* assume no transparent color */
- img->transparent = -1;
-
- /* skip most extensions */
- while (((unsigned char)f->GetC()) == 0x21) /* separator */
- {
- if (((unsigned char)f->GetC()) == 0xF9) /* graphic control ext. */
- {
- f->Read(buf, 6);
- if (buf[1] & 0x01)
- img->transparent = buf[4];
- }
- else
- while ((i = (unsigned char)f->GetC()) != 0) /* byte count */
- f->SeekI(i, wxFromCurrent);
- }
-
- /* read image descriptor block (IDB) */
- f->Read(buf, 9);
- img->w = buf[4] + 256 * buf[5];
- img->h = buf[6] + 256 * buf[7];
- size = img->w * img->h;
- interl = ((buf[8] & 0x40)? 1 : 0);
-
- /* load local color map if available */
- if ((buf[8] & 0x80) == 0x80)
- {
- ncolors = 2 << (buf[8] & 0x07);
- f->Read(pal, 3 * ncolors);
- }
-
- /* get initial code size from first byte in raster data */
- bits = (unsigned char)f->GetC();
-
- /* allocate memory for image and palette */
- if ((img->p = (unsigned char*) malloc(size)) == NULL) return E_MEMORIA;
- if ((img->pal = (unsigned char*) malloc(768)) == NULL) return E_MEMORIA;
-
- /* shift palette to fit VGA 6-bit format */
- for (i = 0; i < 768; i++)
- (img->pal)[i] = (unsigned char)pal[i]; /* >> 2 not in wxWin */
-
- /* decode GIF */
- dgif(img, interl, bits);
-
- /* finish successfully :-) */
- return E_OK;
-}
-
-
projects / wxWidgets.git / blobdiff