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Aegisub/aegisub/libass/ass_font.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 "config.h"
#include <inttypes.h>
#include <ft2build.h>
#include FT_FREETYPE_H
#include FT_SYNTHESIS_H
#include FT_GLYPH_H
#include FT_TRUETYPE_TABLES_H
#include "ass.h"
#include "ass_library.h"
#include "ass_font.h"
#include "ass_bitmap.h"
#include "ass_cache.h"
#include "ass_fontconfig.h"
#include "ass_utils.h"
/**
* Select Microfost Unicode CharMap, if the font has one.
* Otherwise, let FreeType decide.
*/
static void charmap_magic(ass_library_t *library, FT_Face face)
{
int i;
for (i = 0; i < face->num_charmaps; ++i) {
FT_CharMap cmap = face->charmaps[i];
unsigned pid = cmap->platform_id;
unsigned eid = cmap->encoding_id;
if (pid == 3 /*microsoft */
&& (eid == 1 /*unicode bmp */
|| eid == 10 /*full unicode */ )) {
FT_Set_Charmap(face, cmap);
return;
}
}
if (!face->charmap) {
if (face->num_charmaps == 0) {
ass_msg(library, MSGL_WARN, "Font face with no charmaps");
return;
}
ass_msg(library, MSGL_WARN,
"No charmap autodetected, trying the first one");
FT_Set_Charmap(face, face->charmaps[0]);
return;
}
}
static void update_transform(ass_font_t *font)
{
int i;
FT_Matrix m;
m.xx = double_to_d16(font->scale_x);
m.yy = double_to_d16(font->scale_y);
m.xy = m.yx = 0;
for (i = 0; i < font->n_faces; ++i)
FT_Set_Transform(font->faces[i], &m, &font->v);
}
/**
* \brief find a memory font by name
*/
static int find_font(ass_library_t *library, char *name)
{
int i;
for (i = 0; i < library->num_fontdata; ++i)
if (strcasecmp(name, library->fontdata[i].name) == 0)
return i;
return -1;
}
static void face_set_size(FT_Face face, double size);
static void buggy_font_workaround(FT_Face face)
{
// Some fonts have zero Ascender/Descender fields in 'hhea' table.
// In this case, get the information from 'os2' table or, as
// a last resort, from face.bbox.
if (face->ascender + face->descender == 0 || face->height == 0) {
TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
if (os2) {
face->ascender = os2->sTypoAscender;
face->descender = os2->sTypoDescender;
face->height = face->ascender - face->descender;
} else {
face->ascender = face->bbox.yMax;
face->descender = face->bbox.yMin;
face->height = face->ascender - face->descender;
}
}
}
/**
* \brief Select a face with the given charcode and add it to ass_font_t
* \return index of the new face in font->faces, -1 if failed
*/
static int add_face(void *fc_priv, ass_font_t *font, uint32_t ch)
{
char *path;
int index;
FT_Face face;
int error;
int mem_idx;
if (font->n_faces == ASS_FONT_MAX_FACES)
return -1;
path =
fontconfig_select(font->library, fc_priv, font->desc.family,
font->desc.treat_family_as_pattern,
font->desc.bold, font->desc.italic, &index, ch);
if (!path)
return -1;
mem_idx = find_font(font->library, path);
if (mem_idx >= 0) {
error =
FT_New_Memory_Face(font->ftlibrary,
(unsigned char *) font->library->
fontdata[mem_idx].data,
font->library->fontdata[mem_idx].size, 0,
&face);
if (error) {
ass_msg(font->library, MSGL_WARN,
"Error opening memory font: '%s'", path);
free(path);
return -1;
}
} else {
error = FT_New_Face(font->ftlibrary, path, index, &face);
if (error) {
ass_msg(font->library, MSGL_WARN,
"Error opening font: '%s', %d", path, index);
free(path);
return -1;
}
}
charmap_magic(font->library, face);
buggy_font_workaround(face);
font->faces[font->n_faces++] = face;
update_transform(font);
face_set_size(face, font->size);
free(path);
return font->n_faces - 1;
}
/**
* \brief Create a new ass_font_t according to "desc" argument
*/
ass_font_t *ass_font_new(void *font_cache, ass_library_t *library,
FT_Library ftlibrary, void *fc_priv,
ass_font_desc_t *desc)
{
int error;
ass_font_t *fontp;
ass_font_t font;
fontp = ass_font_cache_find((hashmap_t *) font_cache, desc);
if (fontp)
return fontp;
font.library = library;
font.ftlibrary = ftlibrary;
font.n_faces = 0;
font.desc.family = strdup(desc->family);
font.desc.treat_family_as_pattern = desc->treat_family_as_pattern;
font.desc.bold = desc->bold;
font.desc.italic = desc->italic;
font.scale_x = font.scale_y = 1.;
font.v.x = font.v.y = 0;
font.size = 0.;
error = add_face(fc_priv, &font, 0);
if (error == -1) {
free(font.desc.family);
return 0;
} else
return ass_font_cache_add((hashmap_t *) font_cache, &font);
}
/**
* \brief Set font transformation matrix and shift vector
**/
void ass_font_set_transform(ass_font_t *font, double scale_x,
double scale_y, FT_Vector *v)
{
font->scale_x = scale_x;
font->scale_y = scale_y;
font->v.x = v->x;
font->v.y = v->y;
update_transform(font);
}
static void face_set_size(FT_Face face, double size)
{
#if (FREETYPE_MAJOR > 2) || ((FREETYPE_MAJOR == 2) && (FREETYPE_MINOR > 1))
TT_HoriHeader *hori = FT_Get_Sfnt_Table(face, ft_sfnt_hhea);
TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
double mscale = 1.;
FT_Size_RequestRec rq;
FT_Size_Metrics *m = &face->size->metrics;
// VSFilter uses metrics from TrueType OS/2 table
// The idea was borrowed from asa (http://asa.diac24.net)
if (hori && os2) {
int hori_height = hori->Ascender - hori->Descender;
int os2_height = os2->usWinAscent + os2->usWinDescent;
if (hori_height && os2_height)
mscale = (double) hori_height / os2_height;
}
memset(&rq, 0, sizeof(rq));
rq.type = FT_SIZE_REQUEST_TYPE_REAL_DIM;
rq.width = 0;
rq.height = double_to_d6(size * mscale);
rq.horiResolution = rq.vertResolution = 0;
FT_Request_Size(face, &rq);
m->ascender /= mscale;
m->descender /= mscale;
m->height /= mscale;
#else
FT_Set_Char_Size(face, 0, double_to_d6(size), 0, 0);
#endif
}
/**
* \brief Set font size
**/
void ass_font_set_size(ass_font_t *font, double size)
{
int i;
if (font->size != size) {
font->size = size;
for (i = 0; i < font->n_faces; ++i)
face_set_size(font->faces[i], size);
}
}
/**
* \brief Get maximal font ascender and descender.
* \param ch character code
* The values are extracted from the font face that provides glyphs for the given character
**/
void ass_font_get_asc_desc(ass_font_t *font, uint32_t ch, int *asc,
int *desc)
{
int i;
for (i = 0; i < font->n_faces; ++i) {
FT_Face face = font->faces[i];
if (FT_Get_Char_Index(face, ch)) {
int y_scale = face->size->metrics.y_scale;
*asc = FT_MulFix(face->ascender, y_scale);
*desc = FT_MulFix(-face->descender, y_scale);
return;
}
}
*asc = *desc = 0;
}
/*
* Strike a glyph with a horizontal line; it's possible to underline it
* and/or strike through it. For the line's position and size, truetype
* tables are consulted. Obviously this relies on the data in the tables
* being accurate.
*
*/
static int ass_strike_outline_glyph(FT_Face face, ass_font_t *font,
FT_Glyph glyph, int under, int through)
{
TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
TT_Postscript *ps = FT_Get_Sfnt_Table(face, ft_sfnt_post);
FT_Outline *ol = &((FT_OutlineGlyph) glyph)->outline;
int bear, advance, y_scale, i;
// Grow outline
i = (under ? 4 : 0) + (through ? 4 : 0);
ol->points = realloc(ol->points, sizeof(FT_Vector) *
(ol->n_points + i));
ol->tags = realloc(ol->tags, ol->n_points + i);
i = !!under + !!through;
ol->contours = realloc(ol->contours, sizeof(short) *
(ol->n_contours + i));
// If the bearing is negative, the glyph starts left of the current
// pen position
bear = FFMIN(face->glyph->metrics.horiBearingX, 0);
// We're adding half a pixel to avoid small gaps
advance = d16_to_d6(glyph->advance.x) + 32;
y_scale = face->size->metrics.y_scale;
// Add points to the outline
if (under) {
int pos, size;
pos = FT_MulFix(ps->underlinePosition, y_scale * font->scale_y);
size = FT_MulFix(ps->underlineThickness,
y_scale * font->scale_y / 2);
if (pos > 0 || size <= 0)
return 0;
FT_Vector points[4] = {
{.x = bear, .y = pos + size},
{.x = advance, .y = pos + size},
{.x = advance, .y = pos - size},
{.x = bear, .y = pos - size},
};
for (i = 0; i < 4; i++) {
ol->points[ol->n_points] = points[i];
ol->tags[ol->n_points++] = 1;
}
ol->contours[ol->n_contours++] = ol->n_points - 1;
}
if (through) {
int pos, size;
pos = FT_MulFix(os2->yStrikeoutPosition, y_scale * font->scale_y);
size = FT_MulFix(os2->yStrikeoutSize, y_scale * font->scale_y / 2);
if (pos < 0 || size <= 0)
return 0;
FT_Vector points[4] = {
{.x = bear, .y = pos + size},
{.x = advance, .y = pos + size},
{.x = advance, .y = pos - size},
{.x = bear, .y = pos - size},
};
for (i = 0; i < 4; i++) {
ol->points[ol->n_points] = points[i];
ol->tags[ol->n_points++] = 1;
}
ol->contours[ol->n_contours++] = ol->n_points - 1;
}
return 1;
}
/**
* \brief Get a glyph
* \param ch character code
**/
FT_Glyph ass_font_get_glyph(void *fontconfig_priv, ass_font_t *font,
uint32_t ch, ass_hinting_t hinting, int deco)
{
int error;
int index = 0;
int i;
FT_Glyph glyph;
FT_Face face = 0;
int flags = 0;
if (ch < 0x20)
return 0;
if (font->n_faces == 0)
return 0;
for (i = 0; i < font->n_faces; ++i) {
face = font->faces[i];
index = FT_Get_Char_Index(face, ch);
if (index)
break;
}
#ifdef CONFIG_FONTCONFIG
if (index == 0) {
int face_idx;
ass_msg(font->library, MSGL_INFO,
"Glyph 0x%X not found, selecting one more "
"font for (%s, %d, %d)", ch, font->desc.family,
font->desc.bold, font->desc.italic);
face_idx = add_face(fontconfig_priv, font, ch);
if (face_idx >= 0) {
face = font->faces[face_idx];
index = FT_Get_Char_Index(face, ch);
if (index == 0) {
ass_msg(font->library, MSGL_ERR,
"Glyph 0x%X not found in font for (%s, %d, %d)",
ch, font->desc.family, font->desc.bold,
font->desc.italic);
}
}
}
#endif
switch (hinting) {
case ASS_HINTING_NONE:
flags = FT_LOAD_NO_HINTING;
break;
case ASS_HINTING_LIGHT:
flags = FT_LOAD_FORCE_AUTOHINT | FT_LOAD_TARGET_LIGHT;
break;
case ASS_HINTING_NORMAL:
flags = FT_LOAD_FORCE_AUTOHINT;
break;
case ASS_HINTING_NATIVE:
flags = 0;
break;
}
error = FT_Load_Glyph(face, index, FT_LOAD_NO_BITMAP | flags);
if (error) {
ass_msg(font->library, MSGL_WARN, "Error loading glyph, index %d",
index);
return 0;
}
#if (FREETYPE_MAJOR > 2) || \
((FREETYPE_MAJOR == 2) && (FREETYPE_MINOR >= 2)) || \
((FREETYPE_MAJOR == 2) && (FREETYPE_MINOR == 1) && (FREETYPE_PATCH >= 10))
// FreeType >= 2.1.10 required
if (!(face->style_flags & FT_STYLE_FLAG_ITALIC) &&
(font->desc.italic > 55)) {
FT_GlyphSlot_Oblique(face->glyph);
}
#endif
error = FT_Get_Glyph(face->glyph, &glyph);
if (error) {
ass_msg(font->library, MSGL_WARN, "Error loading glyph, index %d",
index);
return 0;
}
ass_strike_outline_glyph(face, font, glyph, deco & DECO_UNDERLINE,
deco & DECO_STRIKETHROUGH);
return glyph;
}
/**
* \brief Get kerning for the pair of glyphs.
**/
FT_Vector ass_font_get_kerning(ass_font_t *font, uint32_t c1, uint32_t c2)
{
FT_Vector v = { 0, 0 };
int i;
for (i = 0; i < font->n_faces; ++i) {
FT_Face face = font->faces[i];
int i1 = FT_Get_Char_Index(face, c1);
int i2 = FT_Get_Char_Index(face, c2);
if (i1 && i2) {
if (FT_HAS_KERNING(face))
FT_Get_Kerning(face, i1, i2, FT_KERNING_DEFAULT, &v);
return v;
}
if (i1 || i2) // these glyphs are from different font faces, no kerning information
return v;
}
return v;
}
/**
* \brief Deallocate ass_font_t
**/
void ass_font_free(ass_font_t *font)
{
int i;
for (i = 0; i < font->n_faces; ++i)
if (font->faces[i])
FT_Done_Face(font->faces[i]);
if (font->desc.family)
free(font->desc.family);
free(font);
}
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