/* extract a portion of an image creating a new image */
static t_tgaimg * area2img(t_tgaimg *src, int x, int y, int width, int height, t_tgaimgtype type) {
t_tgaimg *dst;
int pixelsize;
unsigned char *datap;
unsigned char *destp;
int i;
if (src == NULL) return NULL;
if ((x+width)>src->width) return NULL;
if ((y+height)>src->height) return NULL;
pixelsize = getpixelsize(src);
if (pixelsize == 0) return NULL;
dst = new_tgaimg(width,height,src->bpp,type);
dst->data = malloc(width*height*pixelsize);
datap = src->data;
datap += y*src->width*pixelsize;
destp = dst->data;
for (i = 0; i < height; i++) {
datap += x*pixelsize;
memcpy(destp,datap,width*pixelsize);
destp += width*pixelsize;
datap += (src->width-x)*pixelsize;
}
return dst;
}
int RLE_compress(std::FILE *f, t_tgaimg const *img) {
int pixelsize;
unsigned char const *datap;
unsigned char *pktdata;
unsigned int pktlen;
t_tgapkttype pkttype;
unsigned char *pktdatap;
unsigned int actual=0,perceived=0;
int i;
pkttype = RAW;
pktdatap = NULL;
if (img == NULL) return -1;
if (img->data == NULL) return -1;
pixelsize = getpixelsize(img);
if (pixelsize == 0) return -1;
datap = img->data;
pktdata = (unsigned char*)xmalloc(img->width*img->height*pixelsize);
pktlen = 0;
for (i=0; i<img->width*img->height; ) {
if (pktlen == 0) {
pktdatap = pktdata;
std::memcpy(pktdatap,datap,pixelsize);
pktlen++;
i++;
pktdatap += pixelsize;
datap += pixelsize;
pkttype = RAW;
continue;
}
if (pktlen == 1) {
if (std::memcmp(datap-pixelsize,datap,pixelsize)==0) {
pkttype = RLE;
}
}
if (pkttype == RLE) {
if (std::memcmp(datap-pixelsize,datap,pixelsize)!=0 || pktlen>=128) {
RLE_write_pkt(f,pkttype,pktlen,pktdata,pixelsize);
actual += 1+pixelsize;
perceived += pixelsize*pktlen;
pktlen = 0;
} else {
pktlen++;
i++;
datap += pixelsize;
}
} else {
if (std::memcmp(datap-pixelsize,datap,pixelsize)==0 || pktlen>=129) {
datap -= pixelsize; /* push back last pixel */
i--;
if (i<0) std::fprintf(stderr,"BUG!\n");
pktlen--;
RLE_write_pkt(f,pkttype,pktlen,pktdata,pixelsize);
actual += 1+pixelsize*pktlen;
perceived += pixelsize*pktlen;
pktlen = 0;
} else {
std::memcpy(pktdatap,datap,pixelsize);
pktlen++;
i++;
pktdatap += pixelsize;
datap += pixelsize;
}
}
}
if (pktlen) {
RLE_write_pkt(f,pkttype,pktlen,pktdata,pixelsize);
if (pkttype==RLE) {
actual += 1+pixelsize;
perceived += pixelsize*pktlen;
} else {
actual += 1+pixelsize*pktlen;
perceived += pixelsize*pktlen;
}
pktlen = 0;
}
std::fprintf(stderr,"RLE_compress: wrote %u bytes (%u uncompressed)\n",actual,perceived);
return 0;
}
