summaryrefslogtreecommitdiffstats
path: root/libass/ass_bitmap.c
blob: 15d583ac48fe6ece292494dc4ab7979cdc95d125 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
// -*- 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 file is part of libass.
 *
 * libass 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.
 *
 * libass 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 libass; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, 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;

	double radius;
};

static const unsigned int maxcolor = 255;
static const unsigned base = 256;

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;

	if (priv->radius == radius)
		return 0;
	else
		priv->radius = radius;

	priv->g_r = ceil(radius);
	priv->g_w = 2*priv->g_r+1;

	if (priv->g_r) {
		priv->g = realloc(priv->g, priv->g_w * sizeof(unsigned));
		priv->gt2 = realloc(priv->gt2, 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(double radius)
{
	ass_synth_priv_t* priv = calloc(1, sizeof(ass_synth_priv_t));
	generate_tables(priv, 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 int check_glyph_area(FT_Glyph glyph)
{
	FT_BBox bbox;
	long long dx, dy;
	FT_Glyph_Get_CBox(glyph, FT_GLYPH_BBOX_TRUNCATE, &bbox);
	dx = bbox.xMax - bbox.xMin;
	dy = bbox.yMax - bbox.yMin;
	if (dx * dy > 8000000) {
		mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_GlyphBBoxTooLarge, (int)dx, (int)dy);
		return 1;
	} else
		return 0;
}

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;

	if (check_glyph_area(glyph))
		return 0;
	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;
	}

	FT_Done_Glyph(glyph);
	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 - (c_g/2) : 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;
}

/**
 * \brief Blur with [[1,2,1]. [2,4,2], [1,2,1]] kernel
 * This blur is the same as the one employed by vsfilter.
 */
static void be_blur(unsigned char *buf, int w, int h) {
	unsigned int x, y;
	unsigned int old_sum, new_sum;

	for (y=0; y<h; y++) {
		old_sum = 2 * buf[y*w];
		for (x=0; x<w-1; x++) {
			new_sum = buf[y*w+x] + buf[y*w+x+1];
			buf[y*w+x] = (old_sum + new_sum) >> 2;
			old_sum = new_sum;
		}
	}

	for (x=0; x<w; x++) {
		old_sum = 2 * buf[x];
		for (y=0; y<h-1; y++) {
			new_sum = buf[y*w+x] + buf[(y+1)*w+x];
			buf[y*w+x] = (old_sum + new_sum) >> 2;
			old_sum = new_sum;
		}
	}
}

int glyph_to_bitmap(ass_synth_priv_t* priv_blur,
		FT_Glyph glyph, FT_Glyph outline_glyph, bitmap_t** bm_g,
		bitmap_t** bm_o, bitmap_t** bm_s, int be, double blur_radius)
{
	int bord = be ? (be/4+1) : 0;
	blur_radius *= 2;
	bord = (blur_radius > 0.0) ? blur_radius : bord;

	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_blur, (*bm_o)->w, (*bm_o)->h);
	resize_tmp(priv_blur, (*bm_g)->w, (*bm_g)->h);

	if (be) {
		while (be--) {
			if (*bm_o)
				be_blur((*bm_o)->buffer, (*bm_o)->w, (*bm_o)->h);
			else
				be_blur((*bm_g)->buffer, (*bm_g)->w, (*bm_g)->h);
		}
	} else {
		if (blur_radius > 0.0) {
			generate_tables(priv_blur, blur_radius);
			if (*bm_o)
				blur((*bm_o)->buffer, priv_blur->tmp, (*bm_o)->w, (*bm_o)->h, (*bm_o)->w, (int*)priv_blur->gt2, priv_blur->g_r, priv_blur->g_w);
			else
				blur((*bm_g)->buffer, priv_blur->tmp, (*bm_g)->w, (*bm_g)->h, (*bm_g)->w, (int*)priv_blur->gt2, priv_blur->g_r, priv_blur->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;
}