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