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/*
* Copyright (C) 2011 Grigori Goronzy <greg@chown.ath.cx>
*
* 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 <fribidi/fribidi.h>
#include <hb-ft.h>
#include "ass_render.h"
#include "ass_shaper.h"
#define MAX_RUNS 30
/**
* \brief Print version information
*/
void ass_shaper_info(ASS_Library *lib)
{
ass_msg(lib, MSGL_V, "Complex text layout enabled, using FriBidi "
FRIBIDI_VERSION " HarfBuzz-ng %s", hb_version_string());
}
/**
* \brief Shape an event's text. Calculates directional runs and shapes them.
* \param text_info event's text
* \param ctypes returns character types
* \param emblevels returns embedding levels (directional runs)
*/
void ass_shaper_shape(TextInfo *text_info, FriBidiCharType *ctypes,
FriBidiLevel *emblevels)
{
int i, j, last_break;
FriBidiParType dir;
FriBidiChar *event_text = calloc(sizeof(*event_text), text_info->length);
FriBidiJoiningType *joins = calloc(sizeof(*joins), text_info->length);
GlyphInfo *glyphs = text_info->glyphs;
// XXX: dynamically allocate
struct {
int offset;
int end;
hb_buffer_t *buf;
hb_font_t *font;
} runs[MAX_RUNS];
// Get bidi character types and embedding levels
last_break = 0;
for (i = 0; i < text_info->length; i++) {
event_text[i] = glyphs[i].symbol;
// embedding levels should be calculated paragraph by paragraph
if (glyphs[i].symbol == '\n' || i == text_info->length - 1) {
//printf("paragraph from %d to %d\n", last_break, i);
dir = FRIBIDI_PAR_ON;
fribidi_get_bidi_types(event_text + last_break, i - last_break + 1,
ctypes + last_break);
fribidi_get_par_embedding_levels(ctypes + last_break,
i - last_break + 1, &dir, emblevels + last_break);
last_break = i + 1;
}
}
// add embedding levels to shape runs for final runs
for (i = 0; i < text_info->length; i++) {
glyphs[i].shape_run_id += emblevels[i];
}
#if 0
printf("levels ");
for (i = 0; i < text_info->length; i++) {
printf("%d ", glyphs[i].shape_run_id);
}
printf("\n");
#endif
#if 0
// Use FriBidi's shaper for mirroring and simple Arabic shaping
fribidi_get_joining_types(event_text, text_info->length, joins);
fribidi_join_arabic(ctypes, text_info->length, emblevels, joins);
fribidi_shape(FRIBIDI_FLAGS_DEFAULT | FRIBIDI_FLAGS_ARABIC, emblevels,
text_info->length, joins, event_text);
#endif
// Shape runs with HarfBuzz-ng
int run = 0;
for (i = 0; i < text_info->length && run < MAX_RUNS; i++, run++) {
// get length and level of the current run
int k = i;
int level = glyphs[i].shape_run_id;
while (i < (text_info->length - 1) && level == glyphs[i+1].shape_run_id)
i++;
//printf("run %d from %d to %d with level %d\n", run, k, i, level);
FT_Face run_font = glyphs[k].font->faces[glyphs[k].face_index];
runs[run].offset = k;
runs[run].end = i;
runs[run].buf = hb_buffer_create(i - k + 1);
runs[run].font = hb_ft_font_create(run_font, NULL);
hb_buffer_set_direction(runs[run].buf, (level % 2) ? HB_DIRECTION_RTL :
HB_DIRECTION_LTR);
hb_buffer_add_utf32(runs[run].buf, event_text + k, i - k + 1,
0, i - k + 1);
hb_shape(runs[run].font, runs[run].buf, NULL, 0);
}
//printf("shaped %d runs\n", run);
// Initialize: skip all glyphs, this is undone later as needed
for (i = 0; i < text_info->length; i++)
glyphs[i].skip = 1;
// Update glyph indexes, positions and advances from the shaped runs
for (i = 0; i < run; i++) {
int num_glyphs = hb_buffer_get_length(runs[i].buf);
hb_glyph_info_t *glyph_info = hb_buffer_get_glyph_infos(runs[i].buf, NULL);
hb_glyph_position_t *pos = hb_buffer_get_glyph_positions(runs[i].buf, NULL);
//printf("run text len %d num_glyphs %d\n", runs[i].end - runs[i].offset + 1,
// num_glyphs);
// Update glyphs
for (j = 0; j < num_glyphs; j++) {
int idx = glyph_info[j].cluster + runs[i].offset;
#if 0
printf("run %d cluster %d codepoint %d -> '%c'\n", i, idx,
glyph_info[j].codepoint, event_text[idx]);
printf("position %d %d advance %d %d\n",
pos[j].x_offset, pos[j].y_offset,
pos[j].x_advance, pos[j].y_advance);
#endif
glyphs[idx].skip = 0;
glyphs[idx].glyph_index = glyph_info[j].codepoint;
glyphs[idx].offset.x = pos[j].x_offset * glyphs[idx].scale_x;
glyphs[idx].offset.y = pos[j].y_offset * glyphs[idx].scale_y;
glyphs[idx].advance.x = pos[j].x_advance * glyphs[idx].scale_x;
glyphs[idx].advance.y = pos[j].y_advance * glyphs[idx].scale_y;
}
}
// Free runs and associated data
for (i = 0; i < run; i++) {
hb_buffer_destroy(runs[i].buf);
hb_font_destroy(runs[i].font);
}
// Update glyphs
for (i = 0; i < text_info->length; i++) {
glyphs[i].symbol = event_text[i];
// Skip direction override control characters
// NOTE: Behdad said HarfBuzz is supposed to remove these, but this hasn't
// been implemented yet
if (glyphs[i].symbol <= 0x202F && glyphs[i].symbol >= 0x202a) {
glyphs[i].symbol = 0;
glyphs[i].skip++;
}
}
free(joins);
free(event_text);
}
void ass_shaper_reorder(TextInfo *text_info, FriBidiCharType *ctypes,
FriBidiLevel *emblevels, FriBidiStrIndex *cmap)
{
int i;
FriBidiParType dir;
// Initialize reorder map
for (i = 0; i < text_info->length; i++)
cmap[i] = i;
// Create reorder map line-by-line
for (i = 0; i < text_info->n_lines; i++) {
LineInfo *line = text_info->lines + i;
int level;
dir = FRIBIDI_PAR_ON;
// FIXME: we should actually specify
// the correct paragraph base direction
level = fribidi_reorder_line(FRIBIDI_FLAGS_DEFAULT,
ctypes + line->offset, line->len, 0, dir,
emblevels + line->offset, NULL, cmap + line->offset);
//printf("reorder line %d to level %d\n", i, level);
}
#if 0
printf("map ");
for (i = 0; i < text_info->length; i++) {
printf("%d ", cmap[i]);
}
printf("\n");
#endif
}
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