HarfBuzz text shaping engine
http://harfbuzz.github.io/
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446 lines
15 KiB
446 lines
15 KiB
/* |
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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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(verify ? HB_BUFFER_FLAG_VERIFY : 0) | |
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(unsafe_to_concat ? HB_BUFFER_FLAG_PRODUCE_UNSAFE_TO_CONCAT : 0) | |
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(safe_to_insert_tatweel ? HB_BUFFER_FLAG_PRODUCE_SAFE_TO_INSERT_TATWEEL : 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_not_found_glyph (buffer, not_found_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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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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hb_font_t *font) |
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{ |
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hb_buffer_clear_contents (buffer); |
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if (glyphs) |
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{ |
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/* Call the setup_buffer first while the buffer is empty, |
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* as guess_segment_properties doesn't like glyphs in the buffer. */ |
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setup_buffer (buffer); |
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char *glyphs_text = (char *) text; |
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int glyphs_len = text_len; |
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if (glyphs_len < 0) |
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glyphs_len = strlen (glyphs_text); |
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if (glyphs_len && glyphs_text[glyphs_len - 1] != ']') |
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{ |
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glyphs_text = g_strdup_printf ("%*s]", glyphs_len, glyphs_text); |
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glyphs_len = -1; |
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} |
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hb_buffer_deserialize_glyphs (buffer, |
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glyphs_text, glyphs_len, |
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nullptr, |
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font, |
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HB_BUFFER_SERIALIZE_FORMAT_TEXT); |
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if (!strchr (glyphs_text, '+')) |
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{ |
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scale_advances = false; |
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unsigned count; |
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hb_direction_t direction = hb_buffer_get_direction (buffer); |
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hb_glyph_info_t *infos = hb_buffer_get_glyph_infos (buffer, &count); |
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hb_glyph_position_t *positions = hb_buffer_get_glyph_positions (buffer, &count); |
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for (unsigned i = 0; i < count; i++) |
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hb_font_get_glyph_advance_for_direction (font, |
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infos[i].codepoint, |
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direction, |
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&positions[i].x_advance, |
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&positions[i].y_advance); |
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} |
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if (glyphs_text != text) |
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g_free (glyphs_text); |
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return; |
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} |
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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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if (glyphs) |
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{ |
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/* Scale positions. */ |
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int x_scale, y_scale; |
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hb_font_get_scale (font, &x_scale, &y_scale); |
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unsigned upem = hb_face_get_upem (hb_font_get_face (font)); |
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unsigned count; |
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auto *positions = hb_buffer_get_glyph_positions (buffer, &count); |
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for (unsigned i = 0; i < count; i++) |
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{ |
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auto &pos = positions[i]; |
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pos.x_offset = pos.x_offset * x_scale / upem; |
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pos.y_offset = pos.y_offset * y_scale / upem; |
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if (scale_advances) |
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{ |
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pos.x_advance = pos.x_advance * x_scale / upem; |
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pos.y_advance = pos.y_advance * y_scale / upem; |
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} |
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} |
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} |
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else |
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{ |
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if (advance <= 0) |
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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 = "Shaping failed."; |
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goto fail; |
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} |
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if (advance < 0) |
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{ |
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float unit = (1 << SUBPIXEL_BITS); |
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/* Calculate buffer advance */ |
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float w = 0; |
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unsigned count = 0; |
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hb_glyph_position_t *pos = hb_buffer_get_glyph_positions (buffer, &count); |
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if (HB_DIRECTION_IS_HORIZONTAL (hb_buffer_get_direction (buffer))) |
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for (unsigned i = 0; i < count; i++) |
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w += pos[i].x_advance; |
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else |
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for (unsigned i = 0; i < count; i++) |
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w += pos[i].y_advance; |
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printf ("Default size: %u\n", (unsigned) roundf (w / unit)); |
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exit (0); |
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} |
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} |
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#ifdef HB_EXPERIMENTAL_API |
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else |
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{ |
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float unit = (1 << SUBPIXEL_BITS); |
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float target_advance = advance * unit; |
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float w = 0; |
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hb_tag_t var_tag; |
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float var_value; |
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if (!hb_shape_justify (font, buffer, features, num_features, shapers, |
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target_advance - unit * 0.5f, target_advance + unit * 0.5f, |
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&w, &var_tag, &var_value)) |
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{ |
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if (error) |
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*error = "Shaping failed."; |
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goto fail; |
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} |
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} |
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#endif |
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} |
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if (normalize_glyphs) |
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hb_buffer_normalize_glyphs (buffer); |
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return true; |
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fail: |
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return false; |
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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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signed advance = 0; |
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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_codepoint_t not_found_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 glyphs = false; |
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bool scale_advances = true; |
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hb_bool_t verify = false; |
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hb_bool_t unsafe_to_concat = false; |
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hb_bool_t safe_to_insert_tatweel = 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 = strpbrk (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 = strpbrk (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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#ifdef HB_EXPERIMENTAL_API |
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{"justify-to", 0, 0, |
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G_OPTION_ARG_INT, &this->advance, "Target size to justify to", "SIZE, or -1"}, |
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#endif |
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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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{"not-found-glyph", 0, 0, G_OPTION_ARG_INT, &this->not_found_glyph, "Glyph value to replace not-found characters 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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{"unsafe-to-concat",0, 0, G_OPTION_ARG_NONE, &this->unsafe_to_concat, "Produce unsafe-to-concat glyph flag", nullptr}, |
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{"safe-to-insert-tatweel",0, 0, G_OPTION_ARG_NONE, &this->safe_to_insert_tatweel, "Produce safe-to-insert-tatweel glyph flag", nullptr}, |
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{"glyphs", 0, 0, G_OPTION_ARG_NONE, &this->glyphs, "Interpret input as glyph string", 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" |
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" \"kern[3]\" 1 3 3+1 # Turn feature on, single char\n" |
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"\n" |
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" Mixing it all:\n" |
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"\n" |
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" \"aalt[3:5]=2\" 2 3 5 # Turn 2nd alternate on for range"; |
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GOptionEntry entries2[] = |
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{ |
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{"features", 0, 0, G_OPTION_ARG_CALLBACK, (gpointer) &parse_features, features_help, "list"}, |
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{nullptr} |
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}; |
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parser->add_group (entries2, |
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"features", |
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"Features options:", |
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"Options for font features used", |
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this); |
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} |
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#endif
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