*/
/************************************************************************
- READGIF.H - Leer un archivo GIF de 8 bits
- ------------------------------------------------------------------------
- Tratamiento Digital de la Imagen
+ READGIF.H - Reads a GIF file
------------------------------------------------------------------------
Guillermo Rodriguez Garcia
<guille@iies.es>
- Version: 2.0
+ 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 - Lee un archivo GIF de 256 colores
- ------------------------------------------------------------------------
- Tratamiento Digital de la Imagen
+ READGIF.C - Reads a GIF file
------------------------------------------------------------------------
Guillermo Rodriguez Garcia
<guille@iies.es>
- Version: 2.0
+ Version: 2.1
*************************************************************************/
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);
-
- private:
- int mygetc() {return (unsigned char)f -> GetC();}
- // This is NEEDED! GetC is char (signed) why we need unsigned value
- // from here
+ 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'
- * v2.0 - changed to support 'bits' values < 8
*/
int gifDecoder::getcode(int bits)
{
mask = (1 << bits) - 1;
code = (lastbyte >> (8 - restbits)) & mask;
- /* keep reading new bytes until needed */
+ /* keep reading new bytes while needed */
while (bits > restbits)
{
/* if no bytes left in this block, read the next block */
if (restbyte == 0)
- restbyte = mygetc();
+ restbyte = (unsigned char)f->GetC();
/* read next byte and isolate the bits we need */
- lastbyte = mygetc();
+ 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);
}
+
/* dgif:
* GIF decoding function. The initial code size (aka root size)
* is 'bits'. Supports interlaced images (interl == 1).
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
unsigned char pal[768];
unsigned char buf[16];
+
/* read header and logical screen descriptor block (LSDB) */
- f -> Read(buf, 13);
+ f->Read(buf, 13);
/* check GIF signature */
if (memcmp(buf, "GIF", 3) != 0) return E_FORMATO;
if ((buf[10] & 0x80) == 0x80)
{
ncolors = 2 << (buf[10] & 0x07);
- f -> Read(pal, 3 * ncolors);
+ f->Read(pal, 3 * ncolors);
}
- /* skip extensions */
- while (mygetc() == 0x21) /* separator */
- {
- mygetc(); /* function code */
+ /* assume no transparent color */
+ img->transparent = -1;
- while ((i = mygetc()) != 0) /* byte count */
- f -> SeekI(i, wxFromCurrent);
+ /* 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);
+ 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);
if ((buf[8] & 0x80) == 0x80)
{
ncolors = 2 << (buf[8] & 0x07);
- f -> Read(pal, 3 * ncolors);
+ f->Read(pal, 3 * ncolors);
}
/* get initial code size from first byte in raster data */
- bits = mygetc();
+ bits = (unsigned char)f->GetC();
/* allocate memory for image and palette */
if ((img->p = (unsigned char*) malloc(size)) == 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 needed under wxWin */;
+ (img->pal)[i] = (unsigned char)pal[i]; /* >> 2 not in wxWin */
/* decode GIF */
dgif(img, interl, bits);
return E_OK;
}
+
+
/*
FOLLOWING CODE IS BY V.S. :
decod = new gifDecoder(&stream);
- if (decod -> readgif(&igif) != E_OK) {
- wxLogDebug("Error reading GIF");
+ if (decod->readgif(&igif) != E_OK) {
+ wxLogDebug(_T("Error reading GIF"));
delete decod;
return FALSE;
}
free(igif.p);
return FALSE;
}
- image->SetMask(FALSE);
ptr = image->GetData();
src = igif.p;
pal = igif.pal;
+
+ if (igif.transparent != -1) {
+ for (i = 0; i < 256; i++)
+ if ((pal[3 * i + 0] == 255) && (pal[3 * i + 1] == 0) && (pal[3 * i + 2] == 255)) pal[3 * i + 2] = 254;
+ pal[3 * (igif.transparent) + 0] = 255,
+ pal[3 * (igif.transparent) + 1] = 0,
+ pal[3 * (igif.transparent) + 2] = 255;
+ image->SetMaskColour(255, 0, 255);
+ }
+ else image->SetMask(FALSE);
+
for (i = 0; i < igif.w * igif.h; i++, src++) {
*(ptr++) = pal[3 * (*src) + 0];
*(ptr++) = pal[3 * (*src) + 1];
bool wxGIFHandler::SaveFile( wxImage *image, wxOutputStream& stream )
{
- wxLogDebug("wxGIFHandler is read-only!!");
+ wxLogDebug(_T("wxGIFHandler is read-only!!"));
return FALSE;
}
+
+
+
+
projects / wxWidgets.git / blobdiff