int FrameBufferRawPixel(struct FrameBuffer *ptr,int x,int y,int sze,
unsigned char r,unsigned char g,unsigned char b,
unsigned char a,unsigned char m,
struct FrameBufferClip *clip) {
/* lowest of the low - renders a pixel */
int off;
if (ptr==NULL) return -1;
if (ptr->wdt==0) return -1;
if (ptr->hgt==0) return -1;
if (ptr->img==NULL) return -1;
if (y<0) return 0;
if (x<0) return 0;
if (x>=ptr->wdt) return 0;
if (y>=ptr->hgt) return 0;
if (FrameBufferClip(clip,x,y)==0) return 0;
sze=ptr->wdt*ptr->hgt;
off=y*ptr->wdt+x;
if (ptr->user.pixel !=NULL)
return (ptr->user.pixel) (ptr->wdt,ptr->hgt,ptr->img,ptr->msk,
x,y,ptr->depth,
off,sze,r,g,b,a,ptr->user.data);
if (m & 0x04) ptr->img[off]=r;
if (m & 0x08) ptr->msk[off]=a;
if (ptr->depth !=8) {
if (m & 0x02) ptr->img[off+sze]=g;
if (m & 0x01) ptr->img[off+2*sze]=b;
}
return 0;
}
int FrameBufferRawPixel(struct FrameBuffer *ptr,int x,int y,int sze,
unsigned char r,unsigned char g,unsigned char b,
unsigned char a,unsigned char m,
struct FrameBufferClip *clip) {
/* lowest of the low - renders a pixel */
int off;
float c,ca,cb,t,ta,tb;
if (ptr==NULL) return -1;
if (ptr->wdt==0) return -1;
if (ptr->hgt==0) return -1;
if (ptr->img==NULL) return -1;
if (y<0) return 0;
if (x<0) return 0;
if (x>=ptr->wdt) return 0;
if (y>=ptr->hgt) return 0;
if (FrameBufferClip(clip,x,y)==0) return 0;
sze=ptr->wdt*ptr->hgt;
off=y*ptr->wdt+x;
if (ptr->user.pixel !=NULL)
return (ptr->user.pixel) (ptr->wdt,ptr->hgt,ptr->img,ptr->msk,
x,y,ptr->depth,
off,sze,r,g,b,a,ptr->user.data);
/* direct over painting */
if (m & 0x40) ptr->img[off]=r;
if (m & 0x80) ptr->msk[off]=a;
if (ptr->depth !=8) {
if (m & 0x20) ptr->img[off+sze]=g;
if (m & 0x10) ptr->img[off+2*sze]=b;
}
if ((m &0x0f)==0) return 0; /* nothing else to do */
/* alpha channel to max, so simple replace */
if (a==255) {
if (m & 0x04) ptr->img[off]=r;
if (m & 0x08) ptr->msk[off]=a;
if (ptr->depth !=8) {
if (m & 0x02) ptr->img[off+sze]=g;
if (m & 0x01) ptr->img[off+2*sze]=b;
}
return 0;
}
/* simple porter-duff over compositing */
tb=ptr->msk[off]/255.0;
ta=a/255.0;
t=ta+(tb-ta)*tb;
if (m & 0x08) ptr->msk[off]=(unsigned char) (255.0*t);
if (m & 0x04) {
cb=ptr->img[off]/255.0;
ca=r/255.0;
c=ca*ta+cb*tb*(1-ta);
ptr->img[off]= (unsigned char) (255.0*c);
}
if (ptr->depth==8) return 0;
if (m & 0x02) {
cb=ptr->img[off+sze]/255.0;
ca=g/255.0;
c=ca*ta+cb*tb*(1-ta);
ptr->img[off+sze]= (unsigned char) (255.0*c);
}
if (m & 0x01) {
cb=ptr->img[off+2*sze]/255.0;
ca=b/255.0;
c=ca*ta+cb*tb*(1-ta);
ptr->img[off+2*sze]=(unsigned char) (255.0*c);
}
return 0;
}
