mpv/libass/ass_bitmap.c

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// -*- c-basic-offset: 8; indent-tabs-mode: t -*-
// vim:ts=8:sw=8:noet:ai:
/*
Copyright (C) 2006 Evgeniy Stepanov <eugeni.stepanov@gmail.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <assert.h>
#include <ft2build.h>
#include FT_GLYPH_H
#include "mputils.h"
#include "ass_bitmap.h"
struct ass_synth_priv_s {
int tmp_w, tmp_h;
unsigned short* tmp;
int g_r;
int g_w;
unsigned *g;
unsigned *gt2;
};
static const unsigned int maxcolor = 255;
static const unsigned base = 256;
static const double blur_radius = 1.5;
static int generate_tables(ass_synth_priv_t* priv, double radius)
{
double A = log(1.0/base)/(radius*radius*2);
int mx, i;
double volume_diff, volume_factor = 0;
unsigned volume;
priv->g_r = ceil(radius);
priv->g_w = 2*priv->g_r+1;
if (priv->g_r) {
priv->g = malloc(priv->g_w * sizeof(unsigned));
priv->gt2 = malloc(256 * priv->g_w * sizeof(unsigned));
if (priv->g==NULL || priv->gt2==NULL) {
return -1;
}
}
if (priv->g_r) {
// gaussian curve with volume = 256
for (volume_diff=10000000; volume_diff>0.0000001; volume_diff*=0.5){
volume_factor+= volume_diff;
volume=0;
for (i = 0; i<priv->g_w; ++i) {
priv->g[i] = (unsigned)(exp(A * (i-priv->g_r)*(i-priv->g_r)) * volume_factor + .5);
volume+= priv->g[i];
}
if(volume>256) volume_factor-= volume_diff;
}
volume=0;
for (i = 0; i<priv->g_w; ++i) {
priv->g[i] = (unsigned)(exp(A * (i-priv->g_r)*(i-priv->g_r)) * volume_factor + .5);
volume+= priv->g[i];
}
// gauss table:
for(mx=0;mx<priv->g_w;mx++){
for(i=0;i<256;i++){
priv->gt2[mx+i*priv->g_w] = i*priv->g[mx];
}
}
}
return 0;
}
static void resize_tmp(ass_synth_priv_t* priv, int w, int h)
{
if (priv->tmp_w >= w && priv->tmp_h >= h)
return;
if (priv->tmp_w == 0)
priv->tmp_w = 64;
if (priv->tmp_h == 0)
priv->tmp_h = 64;
while (priv->tmp_w < w) priv->tmp_w *= 2;
while (priv->tmp_h < h) priv->tmp_h *= 2;
if (priv->tmp)
free(priv->tmp);
priv->tmp = malloc((priv->tmp_w + 1) * priv->tmp_h * sizeof(short));
}
ass_synth_priv_t* ass_synth_init(void)
{
ass_synth_priv_t* priv = calloc(1, sizeof(ass_synth_priv_t));
generate_tables(priv, blur_radius);
return priv;
}
void ass_synth_done(ass_synth_priv_t* priv)
{
if (priv->tmp)
free(priv->tmp);
if (priv->g)
free(priv->g);
if (priv->gt2)
free(priv->gt2);
free(priv);
}
static bitmap_t* alloc_bitmap(int w, int h)
{
bitmap_t* bm;
bm = calloc(1, sizeof(bitmap_t));
bm->buffer = malloc(w*h);
bm->w = w;
bm->h = h;
bm->left = bm->top = 0;
return bm;
}
void ass_free_bitmap(bitmap_t* bm)
{
if (bm) {
if (bm->buffer) free(bm->buffer);
free(bm);
}
}
static bitmap_t* copy_bitmap(const bitmap_t* src)
{
bitmap_t* dst = alloc_bitmap(src->w, src->h);
dst->left = src->left;
dst->top = src->top;
memcpy(dst->buffer, src->buffer, src->w * src->h);
return dst;
}
static bitmap_t* glyph_to_bitmap_internal(FT_Glyph glyph, int bord)
{
FT_BitmapGlyph bg;
FT_Bitmap* bit;
bitmap_t* bm;
int w, h;
unsigned char* src;
unsigned char* dst;
int i;
int error;
error = FT_Glyph_To_Bitmap(&glyph, FT_RENDER_MODE_NORMAL, 0, 0);
if (error) {
mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_FT_Glyph_To_BitmapError, error);
return 0;
}
bg = (FT_BitmapGlyph)glyph;
bit = &(bg->bitmap);
if (bit->pixel_mode != FT_PIXEL_MODE_GRAY) {
mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_UnsupportedPixelMode, (int)(bit->pixel_mode));
FT_Done_Glyph(glyph);
return 0;
}
w = bit->width;
h = bit->rows;
bm = alloc_bitmap(w + 2*bord, h + 2*bord);
memset(bm->buffer, 0, bm->w * bm->h);
bm->left = bg->left - bord;
bm->top = - bg->top - bord;
src = bit->buffer;
dst = bm->buffer + bord + bm->w * bord;
for (i = 0; i < h; ++i) {
memcpy(dst, src, w);
src += bit->pitch;
dst += bm->w;
}
return bm;
}
/**
* \brief fix outline bitmap and generate shadow bitmap
* Two things are done here:
* 1. Glyph bitmap is subtracted from outline bitmap. This way looks much better in some cases.
* 2. Shadow bitmap is created as a sum of glyph and outline bitmaps.
*/
static bitmap_t* fix_outline_and_shadow(bitmap_t* bm_g, bitmap_t* bm_o)
{
int x, y;
const int l = bm_o->left > bm_g->left ? bm_o->left : bm_g->left;
const int t = bm_o->top > bm_g->top ? bm_o->top : bm_g->top;
const int r = bm_o->left + bm_o->w < bm_g->left + bm_g->w ? bm_o->left + bm_o->w : bm_g->left + bm_g->w;
const int b = bm_o->top + bm_o->h < bm_g->top + bm_g->h ? bm_o->top + bm_o->h : bm_g->top + bm_g->h;
bitmap_t* bm_s = copy_bitmap(bm_o);
unsigned char* g = bm_g->buffer + (t - bm_g->top) * bm_g->w + (l - bm_g->left);
unsigned char* o = bm_o->buffer + (t - bm_o->top) * bm_o->w + (l - bm_o->left);
unsigned char* s = bm_s->buffer + (t - bm_s->top) * bm_s->w + (l - bm_s->left);
for (y = 0; y < b - t; ++y) {
for (x = 0; x < r - l; ++x) {
unsigned char c_g, c_o;
c_g = g[x];
c_o = o[x];
o[x] = (c_o > c_g) ? c_o : 0;
s[x] = (c_o < 0xFF - c_g) ? c_o + c_g : 0xFF;
}
g += bm_g->w;
o += bm_o->w;
s += bm_s->w;
}
assert(bm_s);
return bm_s;
}
int glyph_to_bitmap(ass_synth_priv_t* priv, FT_Glyph glyph, FT_Glyph outline_glyph,
bitmap_t** bm_g, bitmap_t** bm_o, bitmap_t** bm_s, int be)
{
const int bord = be ? ceil(blur_radius) : 0;
assert(bm_g && bm_o && bm_s);
*bm_g = *bm_o = *bm_s = 0;
if (glyph)
*bm_g = glyph_to_bitmap_internal(glyph, bord);
if (!*bm_g)
return 1;
if (outline_glyph) {
*bm_o = glyph_to_bitmap_internal(outline_glyph, bord);
if (!*bm_o) {
ass_free_bitmap(*bm_g);
return 1;
}
}
if (*bm_o)
resize_tmp(priv, (*bm_o)->w, (*bm_o)->h);
resize_tmp(priv, (*bm_g)->w, (*bm_g)->h);
if (be) {
blur((*bm_g)->buffer, priv->tmp, (*bm_g)->w, (*bm_g)->h, (*bm_g)->w, (int*)priv->gt2, priv->g_r, priv->g_w);
if (*bm_o)
blur((*bm_o)->buffer, priv->tmp, (*bm_o)->w, (*bm_o)->h, (*bm_o)->w, (int*)priv->gt2, priv->g_r, priv->g_w);
}
if (*bm_o)
*bm_s = fix_outline_and_shadow(*bm_g, *bm_o);
else
*bm_s = copy_bitmap(*bm_g);
assert(bm_s);
return 0;
}