HarfBuzz text shaping engine http://harfbuzz.github.io/
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/*
* Copyright © 2011 Google, Inc.
*
* This is part of HarfBuzz, a text shaping library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
* Google Author(s): Behdad Esfahbod
*/
#ifndef SHAPE_OPTIONS_HH
#define SHAPE_OPTIONS_HH
#include "options.hh"
struct shape_options_t
{
~shape_options_t ()
{
g_free (direction);
g_free (language);
g_free (script);
free (features);
g_strfreev (shapers);
}
void add_options (option_parser_t *parser);
void setup_buffer (hb_buffer_t *buffer)
{
hb_buffer_set_direction (buffer, hb_direction_from_string (direction, -1));
hb_buffer_set_script (buffer, hb_script_from_string (script, -1));
hb_buffer_set_language (buffer, hb_language_from_string (language, -1));
hb_buffer_set_flags (buffer, (hb_buffer_flags_t)
(HB_BUFFER_FLAG_DEFAULT |
(bot ? HB_BUFFER_FLAG_BOT : 0) |
(eot ? HB_BUFFER_FLAG_EOT : 0) |
(verify ? HB_BUFFER_FLAG_VERIFY : 0) |
(preserve_default_ignorables ? HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES : 0) |
(remove_default_ignorables ? HB_BUFFER_FLAG_REMOVE_DEFAULT_IGNORABLES : 0) |
0));
hb_buffer_set_invisible_glyph (buffer, invisible_glyph);
hb_buffer_set_not_found_glyph (buffer, not_found_glyph);
hb_buffer_set_cluster_level (buffer, cluster_level);
hb_buffer_guess_segment_properties (buffer);
}
void populate_buffer (hb_buffer_t *buffer, const char *text, int text_len,
const char *text_before, const char *text_after)
{
hb_buffer_clear_contents (buffer);
if (text_before) {
unsigned int len = strlen (text_before);
hb_buffer_add_utf8 (buffer, text_before, len, len, 0);
}
hb_buffer_add_utf8 (buffer, text, text_len, 0, text_len);
if (text_after) {
hb_buffer_add_utf8 (buffer, text_after, -1, 0, 0);
}
if (!utf8_clusters) {
/* Reset cluster values to refer to Unicode character index
* instead of UTF-8 index. */
unsigned int num_glyphs = hb_buffer_get_length (buffer);
hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, nullptr);
for (unsigned int i = 0; i < num_glyphs; i++)
{
info->cluster = i;
info++;
}
}
setup_buffer (buffer);
}
hb_bool_t shape (hb_font_t *font, hb_buffer_t *buffer, const char **error=nullptr)
{
if (!hb_shape_full (font, buffer, features, num_features, shapers))
{
if (error)
*error = "Shaping failed.";
goto fail;
}
if (normalize_glyphs)
hb_buffer_normalize_glyphs (buffer);
return true;
fail:
return false;
}
void shape_closure (const char *text, int text_len,
hb_font_t *font, hb_buffer_t *buffer,
hb_set_t *glyphs)
{
hb_buffer_reset (buffer);
hb_buffer_add_utf8 (buffer, text, text_len, 0, text_len);
setup_buffer (buffer);
hb_ot_shape_glyphs_closure (font, buffer, features, num_features, glyphs);
}
/* Buffer properties */
char *direction = nullptr;
char *language = nullptr;
char *script = nullptr;
/* Buffer flags */
hb_bool_t bot = false;
hb_bool_t eot = false;
hb_bool_t preserve_default_ignorables = false;
hb_bool_t remove_default_ignorables = false;
hb_feature_t *features = nullptr;
unsigned int num_features = 0;
char **shapers = nullptr;
hb_bool_t utf8_clusters = false;
hb_codepoint_t invisible_glyph = 0;
hb_codepoint_t not_found_glyph = 0;
hb_buffer_cluster_level_t cluster_level = HB_BUFFER_CLUSTER_LEVEL_DEFAULT;
hb_bool_t normalize_glyphs = false;
hb_bool_t verify = false;
unsigned int num_iterations = 1;
};
static gboolean
parse_shapers (const char *name G_GNUC_UNUSED,
const char *arg,
gpointer data,
GError **error)
{
shape_options_t *shape_opts = (shape_options_t *) data;
char **shapers = g_strsplit (arg, ",", 0);
for (char **shaper = shapers; *shaper; shaper++)
{
bool found = false;
for (const char **hb_shaper = hb_shape_list_shapers (); *hb_shaper; hb_shaper++) {
if (strcmp (*shaper, *hb_shaper) == 0)
{
found = true;
break;
}
}
if (!found)
{
g_set_error (error, G_OPTION_ERROR, G_OPTION_ERROR_BAD_VALUE,
"Unknown or unsupported shaper: %s", *shaper);
g_strfreev (shapers);
return false;
}
}
g_strfreev (shape_opts->shapers);
shape_opts->shapers = shapers;
return true;
}
static G_GNUC_NORETURN gboolean
list_shapers (const char *name G_GNUC_UNUSED,
const char *arg G_GNUC_UNUSED,
gpointer data G_GNUC_UNUSED,
GError **error G_GNUC_UNUSED)
{
for (const char **shaper = hb_shape_list_shapers (); *shaper; shaper++)
g_printf ("%s\n", *shaper);
exit(0);
}
static gboolean
parse_features (const char *name G_GNUC_UNUSED,
const char *arg,
gpointer data,
GError **error G_GNUC_UNUSED)
{
shape_options_t *shape_opts = (shape_options_t *) data;
char *s = (char *) arg;
size_t l = strlen (s);
char *p;
shape_opts->num_features = 0;
g_free (shape_opts->features);
shape_opts->features = nullptr;
/* if the string is quoted, strip the quotes */
if (s[0] == s[l - 1] && (s[0] == '\"' || s[0] == '\''))
{
s[l - 1] = '\0';
s++;
}
if (!*s)
return true;
/* count the features first, so we can allocate memory */
p = s;
do {
shape_opts->num_features++;
p = strchr (p, ',');
if (p)
p++;
} while (p);
shape_opts->features = (hb_feature_t *) calloc (shape_opts->num_features, sizeof (*shape_opts->features));
if (!shape_opts->features)
return false;
/* now do the actual parsing */
p = s;
shape_opts->num_features = 0;
while (p && *p) {
char *end = strchr (p, ',');
if (hb_feature_from_string (p, end ? end - p : -1, &shape_opts->features[shape_opts->num_features]))
shape_opts->num_features++;
p = end ? end + 1 : nullptr;
}
return true;
}
void
shape_options_t::add_options (option_parser_t *parser)
{
GOptionEntry entries[] =
{
{"list-shapers", 0, G_OPTION_FLAG_NO_ARG,
G_OPTION_ARG_CALLBACK, (gpointer) &list_shapers, "List available shapers and quit", nullptr},
{"shaper", 0, G_OPTION_FLAG_HIDDEN,
G_OPTION_ARG_CALLBACK, (gpointer) &parse_shapers, "Hidden duplicate of --shapers", nullptr},
{"shapers", 0, 0, G_OPTION_ARG_CALLBACK, (gpointer) &parse_shapers, "Set comma-separated list of shapers to try","list"},
{"direction", 0, 0, G_OPTION_ARG_STRING, &this->direction, "Set text direction (default: auto)", "ltr/rtl/ttb/btt"},
{"language", 0, 0, G_OPTION_ARG_STRING, &this->language, "Set text language (default: $LANG)", "BCP 47 tag"},
{"script", 0, 0, G_OPTION_ARG_STRING, &this->script, "Set text script (default: auto)", "ISO-15924 tag"},
{"bot", 0, 0, G_OPTION_ARG_NONE, &this->bot, "Treat text as beginning-of-paragraph", nullptr},
{"eot", 0, 0, G_OPTION_ARG_NONE, &this->eot, "Treat text as end-of-paragraph", nullptr},
{"preserve-default-ignorables",0, 0, G_OPTION_ARG_NONE, &this->preserve_default_ignorables, "Preserve Default-Ignorable characters", nullptr},
{"remove-default-ignorables",0, 0, G_OPTION_ARG_NONE, &this->remove_default_ignorables, "Remove Default-Ignorable characters", nullptr},
{"invisible-glyph", 0, 0, G_OPTION_ARG_INT, &this->invisible_glyph, "Glyph value to replace Default-Ignorables with", nullptr},
{"not-found-glyph", 0, 0, G_OPTION_ARG_INT, &this->not_found_glyph, "Glyph value to replace not-found characters with", nullptr},
{"utf8-clusters", 0, 0, G_OPTION_ARG_NONE, &this->utf8_clusters, "Use UTF8 byte indices, not char indices", nullptr},
{"cluster-level", 0, 0, G_OPTION_ARG_INT, &this->cluster_level, "Cluster merging level (default: 0)", "0/1/2"},
{"normalize-glyphs",0, 0, G_OPTION_ARG_NONE, &this->normalize_glyphs, "Rearrange glyph clusters in nominal order", nullptr},
{"verify", 0, 0, G_OPTION_ARG_NONE, &this->verify, "Perform sanity checks on shaping results", nullptr},
{"num-iterations", 'n', G_OPTION_FLAG_IN_MAIN,
G_OPTION_ARG_INT, &this->num_iterations, "Run shaper N times (default: 1)", "N"},
{nullptr}
};
parser->add_group (entries,
"shape",
"Shape options:",
"Options for the shaping process",
this);
const gchar *features_help = "Comma-separated list of font features\n"
"\n"
" Features can be enabled or disabled, either globally or limited to\n"
" specific character ranges. The format for specifying feature settings\n"
" follows. All valid CSS font-feature-settings values other than 'normal'\n"
" and the global values are also accepted, though not documented below.\n"
" CSS string escapes are not supported."
"\n"
" The range indices refer to the positions between Unicode characters,\n"
" unless the --utf8-clusters is provided, in which case range indices\n"
" refer to UTF-8 byte indices. The position before the first character\n"
" is always 0.\n"
"\n"
" The format is Python-esque. Here is how it all works:\n"
"\n"
" Syntax: Value: Start: End:\n"
"\n"
" Setting value:\n"
" \"kern\" 1 0 ∞ # Turn feature on\n"
" \"+kern\" 1 0 ∞ # Turn feature on\n"
" \"-kern\" 0 0 ∞ # Turn feature off\n"
" \"kern=0\" 0 0 ∞ # Turn feature off\n"
" \"kern=1\" 1 0 ∞ # Turn feature on\n"
" \"aalt=2\" 2 0 ∞ # Choose 2nd alternate\n"
"\n"
" Setting index:\n"
" \"kern[]\" 1 0 ∞ # Turn feature on\n"
" \"kern[:]\" 1 0 ∞ # Turn feature on\n"
" \"kern[5:]\" 1 5 ∞ # Turn feature on, partial\n"
" \"kern[:5]\" 1 0 5 # Turn feature on, partial\n"
" \"kern[3:5]\" 1 3 5 # Turn feature on, range\n"
" \"kern[3]\" 1 3 3+1 # Turn feature on, single char\n"
"\n"
" Mixing it all:\n"
"\n"
" \"aalt[3:5]=2\" 2 3 5 # Turn 2nd alternate on for range";
GOptionEntry entries2[] =
{
{"features", 0, 0, G_OPTION_ARG_CALLBACK, (gpointer) &parse_features, features_help, "list"},
{nullptr}
};
parser->add_group (entries2,
"features",
"Features options:",
"Options for font features used",
this);
}
#endif