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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.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#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 FT_OUTLINE_H
#include <strings.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"
#define VERTICAL_LOWER_BOUND 0x02f1
/**
* Select a good charmap, prefer Microsoft Unicode charmaps.
* Otherwise, let FreeType decide.
*/
static void charmap_magic(ASS_Library *library, FT_Face face)
{
int i;
int ms_cmap = -1;
// Search for a Microsoft Unicode cmap
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;
} else if (pid == 3 && ms_cmap < 0)
ms_cmap = i;
}
// Try the first Microsoft cmap if no Microsoft Unicode cmap was found
if (ms_cmap >= 0) {
FT_CharMap cmap = face->charmaps[ms_cmap];
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;
}
}
/**
* \brief find a memory font by name
*/
static int find_font(ASS_Library *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
* \return index of the new face in font->faces, -1 if failed
*/
static int add_face(void *fc_priv, ASS_Font *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, index,
&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;
face_set_size(face, font->size);
free(path);
return font->n_faces - 1;
}
/**
* \brief Create a new ASS_Font according to "desc" argument
*/
ASS_Font *ass_font_new(void *font_cache, ASS_Library *library,
FT_Library ftlibrary, void *fc_priv,
ASS_FontDesc *desc)
{
int error;
ASS_Font *fontp;
ASS_Font font;
fontp = ass_font_cache_find((Hashmap *) 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.desc.vertical = desc->vertical;
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 *) font_cache, &font);
}
/**
* \brief Set font transformation matrix and shift vector
**/
void ass_font_set_transform(ASS_Font *font, double scale_x,
double scale_y, FT_Vector *v)
{
font->scale_x = scale_x;
font->scale_y = scale_y;
if (v) {
font->v.x = v->x;
font->v.y = v->y;
}
}
static void face_set_size(FT_Face face, double size)
{
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;
}
/**
* \brief Set font size
**/
void ass_font_set_size(ASS_Font *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 *font, uint32_t ch, int *asc,
int *desc)
{
int i;
for (i = 0; i < font->n_faces; ++i) {
FT_Face face = font->faces[i];
TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
if (FT_Get_Char_Index(face, ch)) {
int y_scale = face->size->metrics.y_scale;
if (os2) {
*asc = FT_MulFix(os2->usWinAscent, y_scale);
*desc = FT_MulFix(os2->usWinDescent, y_scale);
} else {
*asc = FT_MulFix(face->ascender, y_scale);
*desc = FT_MulFix(-face->descender, y_scale);
}
if (font->desc.vertical && ch >= VERTICAL_LOWER_BOUND) {
*asc = FT_MulFix(face->max_advance_width, 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 *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, dir;
if (!under && !through)
return 0;
// 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;
// Reverse drawing direction for non-truetype fonts
dir = FT_Outline_Get_Orientation(ol);
// Add points to the outline
if (under && ps) {
int pos = FT_MulFix(ps->underlinePosition, y_scale * font->scale_y);
int size = FT_MulFix(ps->underlineThickness,
y_scale * font->scale_y / 2);
FT_Vector points[4];
if (pos > 0 || size <= 0)
return 1;
points[0].x = bear;
points[0].y = pos + size;
points[1].x = advance;
points[1].y = pos + size;
points[2].x = advance;
points[2].y = pos - size;
points[3].x = bear;
points[3].y = pos - size;
if (dir == FT_ORIENTATION_TRUETYPE) {
for (i = 0; i < 4; i++) {
ol->points[ol->n_points] = points[i];
ol->tags[ol->n_points++] = 1;
}
} else {
for (i = 3; i >= 0; 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 && os2) {
int pos = FT_MulFix(os2->yStrikeoutPosition, y_scale * font->scale_y);
int size = FT_MulFix(os2->yStrikeoutSize, y_scale * font->scale_y / 2);
FT_Vector points[4];
if (pos < 0 || size <= 0)
return 1;
points[0].x = bear;
points[0].y = pos + size;
points[1].x = advance;
points[1].y = pos + size;
points[2].x = advance;
points[2].y = pos - size;
points[3].x = bear;
points[3].y = pos - size;
if (dir == FT_ORIENTATION_TRUETYPE) {
for (i = 0; i < 4; i++) {
ol->points[ol->n_points] = points[i];
ol->tags[ol->n_points++] = 1;
}
} else {
for (i = 3; i >= 0; i--) {
ol->points[ol->n_points] = points[i];
ol->tags[ol->n_points++] = 1;
}
}
ol->contours[ol->n_contours++] = ol->n_points - 1;
}
return 0;
}
/**
* Slightly embold a glyph without touching its metrics
*/
static void ass_glyph_embolden(FT_GlyphSlot slot)
{
int str;
if (slot->format != FT_GLYPH_FORMAT_OUTLINE)
return;
str = FT_MulFix(slot->face->units_per_EM,
slot->face->size->metrics.y_scale) / 64;
FT_Outline_Embolden(&slot->outline, str);
}
/**
* \brief Get a glyph
* \param ch character code
**/
FT_Glyph ass_font_get_glyph(void *fontconfig_priv, ASS_Font *font,
uint32_t ch, ASS_Hinting hinting, int deco)
{
int error;
int index = 0;
int i;
FT_Glyph glyph;
FT_Face face = 0;
int flags = 0;
int vertical = font->desc.vertical;
if (ch < 0x20)
return 0;
// Handle NBSP like a regular space when rendering the glyph
if (ch == 0xa0)
ch = ' ';
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 && face->num_charmaps > 0) {
FT_CharMap cur = face->charmap;
ass_msg(font->library, MSGL_WARN,
"Glyph 0x%X not found, falling back to first charmap", ch);
FT_Set_Charmap(face, face->charmaps[0]);
index = FT_Get_Char_Index(face, ch);
FT_Set_Charmap(face, cur);
}
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
flags = FT_LOAD_NO_BITMAP | FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH
| FT_LOAD_IGNORE_TRANSFORM;
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:
break;
}
error = FT_Load_Glyph(face, index, flags);
if (error) {
ass_msg(font->library, MSGL_WARN, "Error loading glyph, index %d",
index);
return 0;
}
if (!(face->style_flags & FT_STYLE_FLAG_ITALIC) &&
(font->desc.italic > 55)) {
FT_GlyphSlot_Oblique(face->glyph);
}
if (!(face->style_flags & FT_STYLE_FLAG_BOLD) &&
(font->desc.bold > 80)) {
ass_glyph_embolden(face->glyph);
}
error = FT_Get_Glyph(face->glyph, &glyph);
if (error) {
ass_msg(font->library, MSGL_WARN, "Error loading glyph, index %d",
index);
return 0;
}
// Rotate glyph, if needed
if (vertical && ch >= VERTICAL_LOWER_BOUND) {
FT_Matrix m = { 0, double_to_d16(-1.0), double_to_d16(1.0), 0 };
FT_Outline_Transform(&((FT_OutlineGlyph) glyph)->outline, &m);
FT_Outline_Translate(&((FT_OutlineGlyph) glyph)->outline,
face->glyph->metrics.vertAdvance,
0);
glyph->advance.x = face->glyph->linearVertAdvance;
}
// Apply scaling and shift
{
FT_Matrix scale = { double_to_d16(font->scale_x), 0, 0,
double_to_d16(font->scale_y) };
FT_Outline *outl = &((FT_OutlineGlyph) glyph)->outline;
FT_Outline_Transform(outl, &scale);
FT_Outline_Translate(outl, font->v.x, font->v.y);
glyph->advance.x *= font->scale_x;
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 *font, uint32_t c1, uint32_t c2)
{
FT_Vector v = { 0, 0 };
int i;
if (font->desc.vertical)
return v;
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
**/
void ass_font_free(ASS_Font *font)
{
int i;
for (i = 0; i < font->n_faces; ++i)
if (font->faces[i])
FT_Done_Face(font->faces[i]);
free(font->desc.family);
free(font);
}
/**
* \brief Calculate the cbox of a series of points
*/
static void
get_contour_cbox(FT_BBox *box, FT_Vector *points, int start, int end)
{
int i;
box->xMin = box->yMin = INT_MAX;
box->xMax = box->yMax = INT_MIN;
for (i = start; i <= end; i++) {
box->xMin = (points[i].x < box->xMin) ? points[i].x : box->xMin;
box->xMax = (points[i].x > box->xMax) ? points[i].x : box->xMax;
box->yMin = (points[i].y < box->yMin) ? points[i].y : box->yMin;
box->yMax = (points[i].y > box->yMax) ? points[i].y : box->yMax;
}
}
/**
* \brief Determine winding direction of a contour
* \return direction; 0 = clockwise
*/
static int get_contour_direction(FT_Vector *points, int start, int end)
{
int i;
long long sum = 0;
int x = points[start].x;
int y = points[start].y;
for (i = start + 1; i <= end; i++) {
sum += x * (points[i].y - y) - y * (points[i].x - x);
x = points[i].x;
y = points[i].y;
}
sum += x * (points[start].y - y) - y * (points[start].x - x);
return sum > 0;
}
/**
* \brief Fix-up stroker result for huge borders by removing inside contours
* that would reverse in size
*/
void fix_freetype_stroker(FT_OutlineGlyph glyph, int border_x, int border_y)
{
int nc = glyph->outline.n_contours;
int begin, stop;
char modified = 0;
char *valid_cont = malloc(nc);
int start = 0;
int end = -1;
FT_BBox *boxes = malloc(nc * sizeof(FT_BBox));
int i, j;
int inside_direction;
inside_direction = FT_Outline_Get_Orientation(&glyph->outline) ==
FT_ORIENTATION_TRUETYPE;
// create a list of cboxes of the contours
for (i = 0; i < nc; i++) {
start = end + 1;
end = glyph->outline.contours[i];
get_contour_cbox(&boxes[i], glyph->outline.points, start, end);
}
// for each contour, check direction and whether it's "outside"
// or contained in another contour
end = -1;
for (i = 0; i < nc; i++) {
int dir;
start = end + 1;
end = glyph->outline.contours[i];
dir = get_contour_direction(glyph->outline.points, start, end);
valid_cont[i] = 1;
if (dir == inside_direction) {
for (j = 0; j < nc; j++) {
if (i == j)
continue;
if (boxes[i].xMin >= boxes[j].xMin &&
boxes[i].xMax <= boxes[j].xMax &&
boxes[i].yMin >= boxes[j].yMin &&
boxes[i].yMax <= boxes[j].yMax)
goto check_inside;
}
/* "inside" contour but we can't find anything it could be
* inside of - assume the font is buggy and it should be
* an "outside" contour, and reverse it */
for (j = 0; j < (end + 1 - start) / 2; j++) {
FT_Vector temp = glyph->outline.points[start + j];
char temp2 = glyph->outline.tags[start + j];
glyph->outline.points[start + j] = glyph->outline.points[end - j];
glyph->outline.points[end - j] = temp;
glyph->outline.tags[start + j] = glyph->outline.tags[end - j];
glyph->outline.tags[end - j] = temp2;
}
dir ^= 1;
}
check_inside:
if (dir == inside_direction) {
FT_BBox box;
int width, height;
get_contour_cbox(&box, glyph->outline.points, start, end);
width = box.xMax - box.xMin;
height = box.yMax - box.yMin;
if (width < border_x * 2 || height < border_y * 2) {
valid_cont[i] = 0;
modified = 1;
}
}
}
// zero-out contours that can be removed; much simpler than copying
if (modified) {
for (i = 0; i < nc; i++) {
if (valid_cont[i])
continue;
begin = (i == 0) ? 0 : glyph->outline.contours[i - 1] + 1;
stop = glyph->outline.contours[i];
for (j = begin; j <= stop; j++) {
glyph->outline.points[j].x = 0;
glyph->outline.points[j].y = 0;
glyph->outline.tags[j] = 0;
}
}
}
free(boxes);
free(valid_cont);
}
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