harfbuzz/util/shape-options.hh

494 lines
16 KiB
C++

/*
* 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) |
(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_cluster_level (buffer, cluster_level);
hb_buffer_guess_segment_properties (buffer);
}
static void copy_buffer_properties (hb_buffer_t *dst, hb_buffer_t *src)
{
hb_segment_properties_t props;
hb_buffer_get_segment_properties (src, &props);
hb_buffer_set_segment_properties (dst, &props);
hb_buffer_set_flags (dst, hb_buffer_get_flags (src));
hb_buffer_set_cluster_level (dst, hb_buffer_get_cluster_level (src));
}
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)
{
hb_buffer_t *text_buffer = nullptr;
if (verify)
{
text_buffer = hb_buffer_create ();
hb_buffer_append (text_buffer, buffer, 0, -1);
}
if (!hb_shape_full (font, buffer, features, num_features, shapers))
{
if (error)
*error = "All shapers failed.";
goto fail;
}
if (normalize_glyphs)
hb_buffer_normalize_glyphs (buffer);
if (verify && !verify_buffer (buffer, text_buffer, font, error))
goto fail;
if (text_buffer)
hb_buffer_destroy (text_buffer);
return true;
fail:
if (text_buffer)
hb_buffer_destroy (text_buffer);
return false;
}
bool verify_buffer (hb_buffer_t *buffer,
hb_buffer_t *text_buffer,
hb_font_t *font,
const char **error=nullptr)
{
if (!verify_buffer_monotone (buffer, error))
return false;
if (!verify_buffer_safe_to_break (buffer, text_buffer, font, error))
return false;
return true;
}
bool verify_buffer_monotone (hb_buffer_t *buffer, const char **error=nullptr)
{
/* Check that clusters are monotone. */
if (cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES ||
cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS)
{
bool is_forward = HB_DIRECTION_IS_FORWARD (hb_buffer_get_direction (buffer));
unsigned int num_glyphs;
hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, &num_glyphs);
for (unsigned int i = 1; i < num_glyphs; i++)
if (info[i-1].cluster != info[i].cluster &&
(info[i-1].cluster < info[i].cluster) != is_forward)
{
if (error)
*error = "clusters are not monotone.";
return false;
}
}
return true;
}
bool verify_buffer_safe_to_break (hb_buffer_t *buffer,
hb_buffer_t *text_buffer,
hb_font_t *font,
const char **error=nullptr)
{
if (cluster_level != HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES &&
cluster_level != HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS)
{
/* Cannot perform this check without monotone clusters.
* Then again, unsafe-to-break flag is much harder to use without
* monotone clusters. */
return true;
}
/* Check that breaking up shaping at safe-to-break is indeed safe. */
hb_buffer_t *fragment = hb_buffer_create ();
hb_buffer_t *reconstruction = hb_buffer_create ();
copy_buffer_properties (reconstruction, buffer);
unsigned int num_glyphs;
hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, &num_glyphs);
unsigned int num_chars;
hb_glyph_info_t *text = hb_buffer_get_glyph_infos (text_buffer, &num_chars);
/* Chop text and shape fragments. */
bool forward = HB_DIRECTION_IS_FORWARD (hb_buffer_get_direction (buffer));
unsigned int start = 0;
unsigned int text_start = forward ? 0 : num_chars;
unsigned int text_end = text_start;
for (unsigned int end = 1; end < num_glyphs + 1; end++)
{
if (end < num_glyphs &&
(info[end].cluster == info[end-1].cluster ||
info[end-(forward?0:1)].mask & HB_GLYPH_FLAG_UNSAFE_TO_BREAK))
continue;
/* Shape segment corresponding to glyphs start..end. */
if (end == num_glyphs)
{
if (forward)
text_end = num_chars;
else
text_start = 0;
}
else
{
if (forward)
{
unsigned int cluster = info[end].cluster;
while (text_end < num_chars && text[text_end].cluster < cluster)
text_end++;
}
else
{
unsigned int cluster = info[end - 1].cluster;
while (text_start && text[text_start - 1].cluster >= cluster)
text_start--;
}
}
assert (text_start < text_end);
if (0)
printf("start %d end %d text start %d end %d\n", start, end, text_start, text_end);
hb_buffer_clear_contents (fragment);
copy_buffer_properties (fragment, buffer);
hb_buffer_flags_t flags = hb_buffer_get_flags (fragment);
if (0 < text_start)
flags = (hb_buffer_flags_t) (flags & ~HB_BUFFER_FLAG_BOT);
if (text_end < num_chars)
flags = (hb_buffer_flags_t) (flags & ~HB_BUFFER_FLAG_EOT);
hb_buffer_set_flags (fragment, flags);
hb_buffer_append (fragment, text_buffer, text_start, text_end);
if (!hb_shape_full (font, fragment, features, num_features, shapers))
{
if (error)
*error = "All shapers failed while shaping fragment.";
hb_buffer_destroy (reconstruction);
hb_buffer_destroy (fragment);
return false;
}
hb_buffer_append (reconstruction, fragment, 0, -1);
start = end;
if (forward)
text_start = text_end;
else
text_end = text_start;
}
bool ret = true;
hb_buffer_diff_flags_t diff = hb_buffer_diff (reconstruction, buffer, (hb_codepoint_t) -1, 0);
if (diff)
{
if (error)
*error = "Safe-to-break test failed.";
ret = false;
/* Return the reconstructed result instead so it can be inspected. */
hb_buffer_set_length (buffer, 0);
hb_buffer_append (buffer, reconstruction, 0, -1);
}
hb_buffer_destroy (reconstruction);
hb_buffer_destroy (fragment);
return ret;
}
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_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},
{"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