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sixel: kill mask, factor out RGBSIZE

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nick black 2021-03-13 12:16:00 -05:00
parent b533d74889
commit b58b091e81
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GPG Key ID: 5F43400C21CBFACC
1 changed files with 31 additions and 29 deletions
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60
src/lib/sixel.c
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@ -1,17 +1,18 @@
#include "internal.h"
#define RGBSIZE 3
static inline void
break_sixel_comps(unsigned char comps[static 3], uint32_t rgba, unsigned char mask){
comps[0] = (ncpixel_r(rgba) & mask) * 100 / 255;
comps[1] = (ncpixel_g(rgba) & mask) * 100 / 255;
comps[2] = (ncpixel_b(rgba) & mask) * 100 / 255;
break_sixel_comps(unsigned char comps[static RGBSIZE], uint32_t rgba){
comps[0] = ncpixel_r(rgba) * 100 / 255;
comps[1] = ncpixel_g(rgba) * 100 / 255;
comps[2] = ncpixel_b(rgba) * 100 / 255;
//fprintf(stderr, "%u %u %u\n", comps[0], comps[1], comps[2]);
}
// FIXME you can have more (or fewer) than 256 registers...detect?
// if we expand this, we'll need another byte per color for dtable lookup
#define MAXCOLORS 256
#define CENTSIZE 4
#define CENTSIZE (4 + (MAXCOLORS > 256))
// first pass: extract up to 256 sixelspace colors over arbitrarily many sixels
// sixelspace is 0..100 corresponding to 0..255, lame =[
@ -29,20 +30,28 @@ typedef struct sixeltable {
static inline int
ctable_to_dtable(const unsigned char* ctable){
return ctable[3];
if(MAXCOLORS > 256){
return ctable[RGBSIZE] * 256 + ctable[RGBSIZE + 1];
}else{
return ctable[RGBSIZE];
}
}
static inline void
dtable_to_ctable(int dtable, unsigned char* ctable){
ctable[3] = dtable % 256;
if(MAXCOLORS > 256){
ctable[RGBSIZE] = dtable / 256;
ctable[RGBSIZE + 1] = dtable % 256;
}else{
ctable[RGBSIZE] = dtable;
}
}
// returns the index at which the provided color can be found *in the
// dtable*, possibly inserting it into the ctable. returns -1 if the
// color is not in the table and the table is full.
// FIXME replace all these 3s
static int
find_color(colortable* ctab, unsigned char comps[static 3]){
find_color(colortable* ctab, unsigned char comps[static RGBSIZE]){
int i;
if(ctab->colors){
int l, r;
@ -51,7 +60,7 @@ find_color(colortable* ctab, unsigned char comps[static 3]){
do{
i = l + (r - l) / 2;
//fprintf(stderr, "%02x%02x%02x L %d R %d m %d\n", comps[0], comps[1], comps[2], l, r, i);
int cmp = memcmp(ctab->table + i * CENTSIZE, comps, 3);
int cmp = memcmp(ctab->table + i * CENTSIZE, comps, RGBSIZE);
if(cmp == 0){
return ctable_to_dtable(ctab->table + i * CENTSIZE);
}
@ -79,7 +88,7 @@ find_color(colortable* ctab, unsigned char comps[static 3]){
}else{
i = 0;
}
memcpy(ctab->table + i * CENTSIZE, comps, 3);
memcpy(ctab->table + i * CENTSIZE, comps, RGBSIZE);
dtable_to_ctable(ctab->colors, ctab->table + i * CENTSIZE);
++ctab->colors;
return ctab->colors - 1;
@ -90,7 +99,7 @@ find_color(colortable* ctab, unsigned char comps[static 3]){
// 100x100x100 sixel colorspace, and built into a table.
static int
extract_ctable_inner(const uint32_t* data, int linesize, int begy, int begx,
int leny, int lenx, sixeltable* stab, unsigned char mask){
int leny, int lenx, sixeltable* stab){
int pos = 0;
for(int visy = begy ; visy < (begy + leny) ; visy += 6){
for(int visx = begx ; visx < (begx + lenx) ; visx += 1){
@ -99,11 +108,11 @@ extract_ctable_inner(const uint32_t* data, int linesize, int begy, int begx,
if(rgba_trans_p(ncpixel_a(*rgb))){
continue;
}
unsigned char comps[3];
break_sixel_comps(comps, *rgb, mask);
unsigned char comps[RGBSIZE];
break_sixel_comps(comps, *rgb);
int c = find_color(stab->ctab, comps);
if(c < 0){
//fprintf(stderr, "FAILED FINDING COLOR AUGH 0x%02x\n", mask);
//fprintf(stderr, "FAILED FINDING COLOR AUGH\n");
return -1;
}
stab->data[c * stab->ctab->sixelcount + pos] |= (1u << (sy - visy));
@ -123,19 +132,13 @@ initialize_stable(sixeltable* stab){
// Use as many of the original colors as we can, but not more than will fit
// into the set of color registers. We're already losing some precision by the
// RGB -> sixelspace conversion (256->100); try with the complete colors, and
// progressively mask more out until they all fit.
// RGB -> sixelspace conversion (256->100); try with the complete colors.
static int
extract_color_table(const uint32_t* data, int linesize, int begy, int begx,
int leny, int lenx, sixeltable* stab, unsigned char* mask){
*mask = 0xff;
while(mask){
initialize_stable(stab);
if(extract_ctable_inner(data, linesize, begy, begx, leny, lenx, stab, *mask) == 0){
return 0;
}
*mask <<= 1;
*mask &= 0xff;
int leny, int lenx, sixeltable* stab){
initialize_stable(stab);
if(extract_ctable_inner(data, linesize, begy, begx, leny, lenx, stab) == 0){
return 0;
}
return -1;
}
@ -274,8 +277,7 @@ int sixel_blit(ncplane* nc, int placey, int placex, int linesize,
free(ctab);
return -1;
}
unsigned char mask;
if(extract_color_table(data, linesize, begy, begx, leny, lenx, &stable, &mask)){
if(extract_color_table(data, linesize, begy, begx, leny, lenx, &stable)){
free(ctab);
free(stable.data);
return -1;