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Aegisub/aegisub/libass/ass_bitmap.c

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/*
* 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 "ass_utils.h"
#include "ass_bitmap.h"
struct ass_synth_priv {
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_SynthPriv *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_SynthPriv *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_SynthPriv *ass_synth_init(double radius)
{
ASS_SynthPriv *priv = calloc(1, sizeof(ASS_SynthPriv));
generate_tables(priv, radius);
return priv;
}
void ass_synth_done(ASS_SynthPriv *priv)
{
if (priv->tmp)
free(priv->tmp);
if (priv->g)
free(priv->g);
if (priv->gt2)
free(priv->gt2);
free(priv);
}
static Bitmap *alloc_bitmap(int w, int h)
{
Bitmap *bm;
bm = calloc(1, sizeof(Bitmap));
bm->buffer = malloc(w * h);
bm->w = w;
bm->h = h;
bm->left = bm->top = 0;
return bm;
}
void ass_free_bitmap(Bitmap *bm)
{
if (bm) {
if (bm->buffer)
free(bm->buffer);
free(bm);
}
}
static Bitmap *copy_bitmap(const Bitmap *src)
{
Bitmap *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(ASS_Library *library, 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) {
ass_msg(library, MSGL_WARN, "Glyph bounding box too large: %dx%dpx",
(int) dx, (int) dy);
return 1;
} else
return 0;
}
static Bitmap *glyph_to_bitmap_internal(ASS_Library *library,
FT_Glyph glyph, int bord)
{
FT_BitmapGlyph bg;
FT_Bitmap *bit;
Bitmap *bm;
int w, h;
unsigned char *src;
unsigned char *dst;
int i;
int error;
if (check_glyph_area(library, glyph))
return 0;
error = FT_Glyph_To_Bitmap(&glyph, FT_RENDER_MODE_NORMAL, 0, 0);
if (error) {
ass_msg(library, MSGL_WARN, "FT_Glyph_To_Bitmap error %d",
error);
return 0;
}
bg = (FT_BitmapGlyph) glyph;
bit = &(bg->bitmap);
if (bit->pixel_mode != FT_PIXEL_MODE_GRAY) {
ass_msg(library, MSGL_WARN, "Unsupported pixel mode: %d",
(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 *fix_outline_and_shadow(Bitmap *bm_g, Bitmap *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 *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 Shift a bitmap by the fraction of a pixel in x and y direction
* expressed in 26.6 fixed point
*/
static void shift_bitmap(unsigned char *buf, int w, int h, int shift_x,
int shift_y)
{
int x, y, b;
// Shift in x direction
if (shift_x > 0) {
for (y = 0; y < h; y++) {
for (x = w - 1; x > 0; x--) {
b = (buf[x + y * w - 1] * shift_x) >> 6;
buf[x + y * w - 1] -= b;
buf[x + y * w] += b;
}
}
} else if (shift_x < 0) {
shift_x = -shift_x;
for (y = 0; y < h; y++) {
for (x = 0; x < w - 1; x++) {
b = (buf[x + y * w + 1] * shift_x) >> 6;
buf[x + y * w + 1] -= b;
buf[x + y * w] += b;
}
}
}
// Shift in y direction
if (shift_y > 0) {
for (x = 0; x < w; x++) {
for (y = h - 1; y > 0; y--) {
b = (buf[x + (y - 1) * w] * shift_y) >> 6;
buf[x + (y - 1) * w] -= b;
buf[x + y * w] += b;
}
}
} else if (shift_y < 0) {
shift_y = -shift_y;
for (x = 0; x < w; x++) {
for (y = 0; y < h - 1; y++) {
b = (buf[x + (y + 1) * w] * shift_y) >> 6;
buf[x + (y + 1) * w] -= b;
buf[x + y * w] += b;
}
}
}
}
/*
* Gaussian blur. An fast pure C implementation from MPlayer.
*/
static void ass_gauss_blur(unsigned char *buffer, unsigned short *tmp2,
int width, int height, int stride, int *m2,
int r, int mwidth)
{
int x, y;
unsigned char *s = buffer;
unsigned short *t = tmp2 + 1;
for (y = 0; y < height; y++) {
memset(t - 1, 0, (width + 1) * sizeof(short));
for (x = 0; x < r; x++) {
const int src = s[x];
if (src) {
register unsigned short *dstp = t + x - r;
int mx;
unsigned *m3 = (unsigned *) (m2 + src * mwidth);
for (mx = r - x; mx < mwidth; mx++) {
dstp[mx] += m3[mx];
}
}
}
for (; x < width - r; x++) {
const int src = s[x];
if (src) {
register unsigned short *dstp = t + x - r;
int mx;
unsigned *m3 = (unsigned *) (m2 + src * mwidth);
for (mx = 0; mx < mwidth; mx++) {
dstp[mx] += m3[mx];
}
}
}
for (; x < width; x++) {
const int src = s[x];
if (src) {
register unsigned short *dstp = t + x - r;
int mx;
const int x2 = r + width - x;
unsigned *m3 = (unsigned *) (m2 + src * mwidth);
for (mx = 0; mx < x2; mx++) {
dstp[mx] += m3[mx];
}
}
}
s += stride;
t += width + 1;
}
t = tmp2;
for (x = 0; x < width; x++) {
for (y = 0; y < r; y++) {
unsigned short *srcp = t + y * (width + 1) + 1;
int src = *srcp;
if (src) {
register unsigned short *dstp = srcp - 1 + width + 1;
const int src2 = (src + 128) >> 8;
unsigned *m3 = (unsigned *) (m2 + src2 * mwidth);
int mx;
*srcp = 128;
for (mx = r - 1; mx < mwidth; mx++) {
*dstp += m3[mx];
dstp += width + 1;
}
}
}
for (; y < height - r; y++) {
unsigned short *srcp = t + y * (width + 1) + 1;
int src = *srcp;
if (src) {
register unsigned short *dstp = srcp - 1 - r * (width + 1);
const int src2 = (src + 128) >> 8;
unsigned *m3 = (unsigned *) (m2 + src2 * mwidth);
int mx;
*srcp = 128;
for (mx = 0; mx < mwidth; mx++) {
*dstp += m3[mx];
dstp += width + 1;
}
}
}
for (; y < height; y++) {
unsigned short *srcp = t + y * (width + 1) + 1;
int src = *srcp;
if (src) {
const int y2 = r + height - y;
register unsigned short *dstp = srcp - 1 - r * (width + 1);
const int src2 = (src + 128) >> 8;
unsigned *m3 = (unsigned *) (m2 + src2 * mwidth);
int mx;
*srcp = 128;
for (mx = 0; mx < y2; mx++) {
*dstp += m3[mx];
dstp += width + 1;
}
}
}
t++;
}
t = tmp2;
s = buffer;
for (y = 0; y < height; y++) {
for (x = 0; x < width; x++) {
s[x] = t[x] >> 8;
}
s += stride;
t += width + 1;
}
}
/**
* \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_Library *library, ASS_SynthPriv *priv_blur,
FT_Glyph glyph, FT_Glyph outline_glyph,
Bitmap **bm_g, Bitmap **bm_o, Bitmap **bm_s,
int be, double blur_radius, FT_Vector shadow_offset,
int border_style)
{
blur_radius *= 2;
int bbord = be > 0 ? sqrt(2 * be) : 0;
int gbord = blur_radius > 0.0 ? blur_radius + 1 : 0;
int bord = FFMAX(bbord, gbord);
if (bord == 0 && (shadow_offset.x || shadow_offset.y))
bord = 1;
assert(bm_g && bm_o && bm_s);
*bm_g = *bm_o = *bm_s = 0;
if (glyph)
*bm_g = glyph_to_bitmap_internal(library, glyph, bord);
if (!*bm_g)
return 1;
if (outline_glyph) {
*bm_o = glyph_to_bitmap_internal(library, outline_glyph, bord);
if (!*bm_o) {
return 1;
}
}
// Apply box blur (multiple passes, if requested)
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);
}
// Apply gaussian blur
if (blur_radius > 0.0) {
if (*bm_o)
resize_tmp(priv_blur, (*bm_o)->w, (*bm_o)->h);
else
resize_tmp(priv_blur, (*bm_g)->w, (*bm_g)->h);
generate_tables(priv_blur, blur_radius);
if (*bm_o)
ass_gauss_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
ass_gauss_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 && border_style == 3)
*bm_s = copy_bitmap(*bm_o);
else if (*bm_o)
*bm_s = fix_outline_and_shadow(*bm_g, *bm_o);
else
*bm_s = copy_bitmap(*bm_g);
shift_bitmap((*bm_s)->buffer, (*bm_s)->w,(*bm_s)->h,
shadow_offset.x, shadow_offset.y);
assert(bm_s);
return 0;
}
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