277 lines
11 KiB
C
277 lines
11 KiB
C
/* pam.c - pam (portable alpha map) utility library
|
|
**
|
|
** Copyright (C) 1989, 1991 by Jef Poskanzer.
|
|
** Copyright (C) 1997, 2000, 2002 by Greg Roelofs; based on an idea by
|
|
** Stefan Schneider.
|
|
** © 2009-2016 by Kornel Lesinski.
|
|
**
|
|
** Permission to use, copy, modify, and distribute this software and its
|
|
** documentation for any purpose and without fee is hereby granted, provided
|
|
** that the above copyright notice appear in all copies and that both that
|
|
** copyright notice and this permission notice appear in supporting
|
|
** documentation. This software is provided "as is" without express or
|
|
** implied warranty.
|
|
*/
|
|
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
|
|
#include "libimagequant.h"
|
|
#include "pam.h"
|
|
#include "mempool.h"
|
|
|
|
LIQ_PRIVATE bool pam_computeacolorhash(struct acolorhash_table *acht, const rgba_pixel *const pixels[], unsigned int cols, unsigned int rows, const unsigned char *importance_map)
|
|
{
|
|
const unsigned int ignorebits = acht->ignorebits;
|
|
const unsigned int channel_mask = 255U>>ignorebits<<ignorebits;
|
|
const unsigned int channel_hmask = (255U>>ignorebits) ^ 0xFFU;
|
|
const unsigned int posterize_mask = channel_mask << 24 | channel_mask << 16 | channel_mask << 8 | channel_mask;
|
|
const unsigned int posterize_high_mask = channel_hmask << 24 | channel_hmask << 16 | channel_hmask << 8 | channel_hmask;
|
|
|
|
const unsigned int hash_size = acht->hash_size;
|
|
|
|
/* Go through the entire image, building a hash table of colors. */
|
|
for(unsigned int row = 0; row < rows; ++row) {
|
|
|
|
float boost=1.0;
|
|
for(unsigned int col = 0; col < cols; ++col) {
|
|
if (importance_map) {
|
|
boost = 0.5f+ (double)*importance_map++/255.f;
|
|
}
|
|
|
|
// RGBA color is casted to long for easier hasing/comparisons
|
|
union rgba_as_int px = {pixels[row][col]};
|
|
unsigned int hash;
|
|
if (!px.rgba.a) {
|
|
// "dirty alpha" has different RGBA values that end up being the same fully transparent color
|
|
px.l=0; hash=0;
|
|
boost = 10;
|
|
} else {
|
|
// mask posterizes all 4 channels in one go
|
|
px.l = (px.l & posterize_mask) | ((px.l & posterize_high_mask) >> (8-ignorebits));
|
|
// fancier hashing algorithms didn't improve much
|
|
hash = px.l % hash_size;
|
|
}
|
|
|
|
if (!pam_add_to_hash(acht, hash, boost, px, row, rows)) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
}
|
|
acht->cols = cols;
|
|
acht->rows += rows;
|
|
return true;
|
|
}
|
|
|
|
LIQ_PRIVATE bool pam_add_to_hash(struct acolorhash_table *acht, unsigned int hash, float boost, union rgba_as_int px, unsigned int row, unsigned int rows)
|
|
{
|
|
/* head of the hash function stores first 2 colors inline (achl->used = 1..2),
|
|
to reduce number of allocations of achl->other_items.
|
|
*/
|
|
struct acolorhist_arr_head *achl = &acht->buckets[hash];
|
|
if (achl->inline1.color.l == px.l && achl->used) {
|
|
achl->inline1.perceptual_weight += boost;
|
|
return true;
|
|
}
|
|
if (achl->used) {
|
|
if (achl->used > 1) {
|
|
if (achl->inline2.color.l == px.l) {
|
|
achl->inline2.perceptual_weight += boost;
|
|
return true;
|
|
}
|
|
// other items are stored as an array (which gets reallocated if needed)
|
|
struct acolorhist_arr_item *other_items = achl->other_items;
|
|
unsigned int i = 0;
|
|
for (; i < achl->used-2; i++) {
|
|
if (other_items[i].color.l == px.l) {
|
|
other_items[i].perceptual_weight += boost;
|
|
return true;
|
|
}
|
|
}
|
|
|
|
// the array was allocated with spare items
|
|
if (i < achl->capacity) {
|
|
other_items[i] = (struct acolorhist_arr_item){
|
|
.color = px,
|
|
.perceptual_weight = boost,
|
|
};
|
|
achl->used++;
|
|
++acht->colors;
|
|
return true;
|
|
}
|
|
|
|
if (++acht->colors > acht->maxcolors) {
|
|
return false;
|
|
}
|
|
|
|
struct acolorhist_arr_item *new_items;
|
|
unsigned int capacity;
|
|
if (!other_items) { // there was no array previously, alloc "small" array
|
|
capacity = 8;
|
|
if (acht->freestackp <= 0) {
|
|
// estimate how many colors are going to be + headroom
|
|
const size_t mempool_size = ((acht->rows + rows-row) * 2 * acht->colors / (acht->rows + row + 1) + 1024) * sizeof(struct acolorhist_arr_item);
|
|
new_items = mempool_alloc(&acht->mempool, sizeof(struct acolorhist_arr_item)*capacity, mempool_size);
|
|
} else {
|
|
// freestack stores previously freed (reallocated) arrays that can be reused
|
|
// (all pesimistically assumed to be capacity = 8)
|
|
new_items = acht->freestack[--acht->freestackp];
|
|
}
|
|
} else {
|
|
const unsigned int stacksize = sizeof(acht->freestack)/sizeof(acht->freestack[0]);
|
|
|
|
// simply reallocs and copies array to larger capacity
|
|
capacity = achl->capacity*2 + 16;
|
|
if (acht->freestackp < stacksize-1) {
|
|
acht->freestack[acht->freestackp++] = other_items;
|
|
}
|
|
const size_t mempool_size = ((acht->rows + rows-row) * 2 * acht->colors / (acht->rows + row + 1) + 32*capacity) * sizeof(struct acolorhist_arr_item);
|
|
new_items = mempool_alloc(&acht->mempool, sizeof(struct acolorhist_arr_item)*capacity, mempool_size);
|
|
if (!new_items) return false;
|
|
memcpy(new_items, other_items, sizeof(other_items[0])*achl->capacity);
|
|
}
|
|
|
|
achl->other_items = new_items;
|
|
achl->capacity = capacity;
|
|
new_items[i] = (struct acolorhist_arr_item){
|
|
.color = px,
|
|
.perceptual_weight = boost,
|
|
};
|
|
achl->used++;
|
|
} else {
|
|
// these are elses for first checks whether first and second inline-stored colors are used
|
|
achl->inline2.color.l = px.l;
|
|
achl->inline2.perceptual_weight = boost;
|
|
achl->used = 2;
|
|
++acht->colors;
|
|
}
|
|
} else {
|
|
achl->inline1.color.l = px.l;
|
|
achl->inline1.perceptual_weight = boost;
|
|
achl->used = 1;
|
|
++acht->colors;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
LIQ_PRIVATE struct acolorhash_table *pam_allocacolorhash(unsigned int maxcolors, unsigned int surface, unsigned int ignorebits, void* (*malloc)(size_t), void (*free)(void*))
|
|
{
|
|
const size_t estimated_colors = MIN(maxcolors, surface/(ignorebits + (surface > 512*512 ? 6 : 5)));
|
|
const size_t hash_size = estimated_colors < 66000 ? 6673 : (estimated_colors < 200000 ? 12011 : 24019);
|
|
|
|
mempool m = NULL;
|
|
const size_t buckets_size = hash_size * sizeof(struct acolorhist_arr_head);
|
|
const size_t mempool_size = sizeof(struct acolorhash_table) + buckets_size + estimated_colors * sizeof(struct acolorhist_arr_item);
|
|
struct acolorhash_table *t = mempool_create(&m, sizeof(*t) + buckets_size, mempool_size, malloc, free);
|
|
if (!t) return NULL;
|
|
*t = (struct acolorhash_table){
|
|
.mempool = m,
|
|
.hash_size = hash_size,
|
|
.maxcolors = maxcolors,
|
|
.ignorebits = ignorebits,
|
|
};
|
|
memset(t->buckets, 0, buckets_size);
|
|
return t;
|
|
}
|
|
|
|
ALWAYS_INLINE static float pam_add_to_hist(const float *gamma_lut, hist_item *achv, unsigned int j, const struct acolorhist_arr_item *entry, const float max_perceptual_weight)
|
|
{
|
|
achv[j].acolor = rgba_to_f(gamma_lut, entry->color.rgba);
|
|
const float w = MIN(entry->perceptual_weight, max_perceptual_weight);
|
|
achv[j].adjusted_weight = achv[j].perceptual_weight = w;
|
|
return w;
|
|
}
|
|
|
|
LIQ_PRIVATE histogram *pam_acolorhashtoacolorhist(const struct acolorhash_table *acht, const double gamma, void* (*malloc)(size_t), void (*free)(void*))
|
|
{
|
|
histogram *hist = malloc(sizeof(hist[0]));
|
|
if (!hist || !acht) return NULL;
|
|
*hist = (histogram){
|
|
.achv = malloc(MAX(1,acht->colors) * sizeof(hist->achv[0])),
|
|
.size = acht->colors,
|
|
.free = free,
|
|
.ignorebits = acht->ignorebits,
|
|
};
|
|
if (!hist->achv) return NULL;
|
|
|
|
float gamma_lut[256];
|
|
to_f_set_gamma(gamma_lut, gamma);
|
|
|
|
/* Limit perceptual weight to 1/10th of the image surface area to prevent
|
|
a single color from dominating all others. */
|
|
float max_perceptual_weight = 0.1f * acht->cols * acht->rows;
|
|
double total_weight = 0;
|
|
|
|
for(unsigned int j=0, i=0; i < acht->hash_size; ++i) {
|
|
const struct acolorhist_arr_head *const achl = &acht->buckets[i];
|
|
if (achl->used) {
|
|
total_weight += pam_add_to_hist(gamma_lut, hist->achv, j++, &achl->inline1, max_perceptual_weight);
|
|
|
|
if (achl->used > 1) {
|
|
total_weight += pam_add_to_hist(gamma_lut, hist->achv, j++, &achl->inline2, max_perceptual_weight);
|
|
|
|
for(unsigned int k=0; k < achl->used-2; k++) {
|
|
total_weight += pam_add_to_hist(gamma_lut, hist->achv, j++, &achl->other_items[k], max_perceptual_weight);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
hist->total_perceptual_weight = total_weight;
|
|
return hist;
|
|
}
|
|
|
|
|
|
LIQ_PRIVATE void pam_freeacolorhash(struct acolorhash_table *acht)
|
|
{
|
|
if (acht) {
|
|
mempool_destroy(acht->mempool);
|
|
}
|
|
}
|
|
|
|
LIQ_PRIVATE void pam_freeacolorhist(histogram *hist)
|
|
{
|
|
hist->free(hist->achv);
|
|
hist->free(hist);
|
|
}
|
|
|
|
LIQ_PRIVATE colormap *pam_colormap(unsigned int colors, void* (*malloc)(size_t), void (*free)(void*))
|
|
{
|
|
assert(colors > 0 && colors < 65536);
|
|
|
|
colormap *map;
|
|
const size_t colors_size = colors * sizeof(map->palette[0]);
|
|
map = malloc(sizeof(colormap) + colors_size);
|
|
if (!map) return NULL;
|
|
*map = (colormap){
|
|
.malloc = malloc,
|
|
.free = free,
|
|
.colors = colors,
|
|
};
|
|
memset(map->palette, 0, colors_size);
|
|
return map;
|
|
}
|
|
|
|
LIQ_PRIVATE colormap *pam_duplicate_colormap(colormap *map)
|
|
{
|
|
colormap *dupe = pam_colormap(map->colors, map->malloc, map->free);
|
|
for(unsigned int i=0; i < map->colors; i++) {
|
|
dupe->palette[i] = map->palette[i];
|
|
}
|
|
return dupe;
|
|
}
|
|
|
|
LIQ_PRIVATE void pam_freecolormap(colormap *c)
|
|
{
|
|
c->free(c);
|
|
}
|
|
|
|
LIQ_PRIVATE void to_f_set_gamma(float gamma_lut[], const double gamma)
|
|
{
|
|
for(int i=0; i < 256; i++) {
|
|
gamma_lut[i] = pow((double)i/255.0, internal_gamma/gamma);
|
|
}
|
|
}
|
|
|