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Count colors when loading True color pictures

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If the count is <= 256 there is no need to execute the expensive
color quantization process
This commit is contained in:
Thomas Bernard 2018-01-16 16:27:30 +01:00
parent 753aaf3422
commit ee11079b86
1 changed files with 41 additions and 3 deletions
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44
src/op_c.c
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@ -1368,6 +1368,41 @@ void Convert_24b_bitmap_to_256_nearest_neighbor(T_Bitmap256 dest,
}
// Count colors and convert if 256 colors or less are used
// return 0 for success
int Try_Convert_to_256_Without_Loss(T_Bitmap256 dest,T_Bitmap24B source,int width,int height,T_Components * palette)
{
int i;
int n = 0; // number of colors
long index;
T_Bitmap24B ptr;
for (index = width * height, ptr = source; index > 0; index--, ptr++)
{
// look for the color in the table
for (i = 0; i < n; i++) {
if(palette[i].R == ptr->R && palette[i].G == ptr->G && palette[i].B == ptr->B)
break; // found !
}
if (i >= n) {
if (n > 255) {
// there are more than 256 colors
return 1;
}
// need to add the color in the palette
palette[n].R = ptr->R;
palette[n].G = ptr->G;
palette[n].B = ptr->B;
n++;
}
*dest = (byte)i;
dest++;
}
// TODO : Sort the palette ?
return 0;
}
// These are the allowed precisions for all the tables.
// For some of them only the first one may work because of ugly optimizations
static const byte precision_24b[]=
@ -1389,13 +1424,16 @@ static const byte precision_24b[]=
// Give this one a 24b source, get back the 256c bitmap and its palette
int Convert_24b_bitmap_to_256(T_Bitmap256 dest,T_Bitmap24B source,int width,int height,T_Components * palette)
{
CT_Tree* table; // table de conversion
int ip; // index de précision pour la conversion
if (Try_Convert_to_256_Without_Loss(dest, source, width, height, palette) == 0)
return 0;
#if defined(__GP2X__) || defined(__gp2x__) || defined(__WIZ__) || defined(__CAANOO__)
return Convert_24b_bitmap_to_256_fast(dest, source, width, height, palette);
#else
CT_Tree* table; // table de conversion
int ip; // index de précision pour la conversion
// On essaye d'obtenir une table de conversion qui loge en mémoire, avec la
// meilleure précision possible
for (ip=0;ip<(10*3);ip+=3)