p_img->dst_y < i_y || p_img->dst_y + p_img->h > i_y + i_height )
continue;
- const int r = (p_img->color >> 24)&0xff;
- const int g = (p_img->color >> 16)&0xff;
- const int b = (p_img->color >> 8)&0xff;
- const int a = (p_img->color )&0xff;
+ const unsigned r = (p_img->color >> 24)&0xff;
+ const unsigned g = (p_img->color >> 16)&0xff;
+ const unsigned b = (p_img->color >> 8)&0xff;
+ const unsigned a = (p_img->color )&0xff;
int x, y;
for( y = 0; y < p_img->h; y++ )
{
for( x = 0; x < p_img->w; x++ )
{
- const int alpha = p_img->bitmap[y*p_img->stride+x];
- const int an = (255 - a) * alpha / 255;
+ const unsigned alpha = p_img->bitmap[y*p_img->stride+x];
+ const unsigned an = (255 - a) * alpha / 255;
uint8_t *p_rgba = &p->p_pixels[(y+p_img->dst_y-i_y) * p->i_pitch + 4 * (x+p_img->dst_x-i_x)];
+ const unsigned ao = p_rgba[3];
/* Native endianness, but RGBA ordering */
- p_rgba[0] = ( p_rgba[0] * (255-an) + r * an ) / 255;
- p_rgba[1] = ( p_rgba[1] * (255-an) + g * an ) / 255;
- p_rgba[2] = ( p_rgba[2] * (255-an) + b * an ) / 255;
- p_rgba[3] = 255 - ( 255 - p_rgba[3] ) * ( 255 - an ) / 255;
+ if( ao == 0 )
+ {
+ /* Optimized but the else{} will produce the same result */
+ p_rgba[0] = r;
+ p_rgba[1] = g;
+ p_rgba[2] = b;
+ p_rgba[3] = an;
+ }
+ else
+ {
+ p_rgba[3] = 255 - ( 255 - p_rgba[3] ) * ( 255 - an ) / 255;
+ if( p_rgba[3] != 0 )
+ {
+ p_rgba[0] = ( p_rgba[0] * ao * (255-an) / 255 + r * an ) / p_rgba[3];
+ p_rgba[1] = ( p_rgba[1] * ao * (255-an) / 255 + g * an ) / p_rgba[3];
+ p_rgba[2] = ( p_rgba[2] * ao * (255-an) / 255 + b * an ) / p_rgba[3];
+ }
+ }
}
}
}