449 lines
12 KiB
C++
449 lines
12 KiB
C++
/*
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* Copyright © 2009,2010 Red Hat, Inc.
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* Copyright © 2010,2011 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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* Red Hat Author(s): Behdad Esfahbod
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* Google Author(s): Behdad Esfahbod
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*/
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#include "hb-ot-shape-private.hh"
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#include "hb-ot-shape-complex-private.hh"
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#include "hb-font-private.hh"
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hb_tag_t common_features[] = {
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HB_TAG('c','c','m','p'),
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HB_TAG('l','o','c','l'),
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HB_TAG('m','a','r','k'),
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HB_TAG('m','k','m','k'),
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HB_TAG('r','l','i','g'),
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};
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hb_tag_t horizontal_features[] = {
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HB_TAG('c','a','l','t'),
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HB_TAG('c','l','i','g'),
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HB_TAG('c','u','r','s'),
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HB_TAG('k','e','r','n'),
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HB_TAG('l','i','g','a'),
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};
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/* Note:
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* Technically speaking, vrt2 and vert are mutually exclusive.
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* According to the spec, valt and vpal are also mutually exclusive.
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* But we apply them all for now.
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*/
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hb_tag_t vertical_features[] = {
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HB_TAG('v','a','l','t'),
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HB_TAG('v','e','r','t'),
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HB_TAG('v','k','r','n'),
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HB_TAG('v','p','a','l'),
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HB_TAG('v','r','t','2'),
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};
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static void
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hb_ot_shape_collect_features (hb_ot_shape_planner_t *planner,
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const hb_segment_properties_t *props,
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const hb_feature_t *user_features,
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unsigned int num_user_features)
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{
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switch (props->direction) {
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case HB_DIRECTION_LTR:
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planner->map.add_bool_feature (HB_TAG ('l','t','r','a'));
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planner->map.add_bool_feature (HB_TAG ('l','t','r','m'));
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break;
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case HB_DIRECTION_RTL:
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planner->map.add_bool_feature (HB_TAG ('r','t','l','a'));
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planner->map.add_bool_feature (HB_TAG ('r','t','l','m'), false);
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break;
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case HB_DIRECTION_TTB:
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case HB_DIRECTION_BTT:
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case HB_DIRECTION_INVALID:
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default:
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break;
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}
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#define ADD_FEATURES(array) \
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HB_STMT_START { \
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for (unsigned int i = 0; i < ARRAY_LENGTH (array); i++) \
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planner->map.add_bool_feature (array[i]); \
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} HB_STMT_END
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hb_ot_shape_complex_collect_features (planner->shaper, &planner->map, props);
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ADD_FEATURES (common_features);
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if (HB_DIRECTION_IS_HORIZONTAL (props->direction))
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ADD_FEATURES (horizontal_features);
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else
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ADD_FEATURES (vertical_features);
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#undef ADD_FEATURES
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for (unsigned int i = 0; i < num_user_features; i++) {
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const hb_feature_t *feature = &user_features[i];
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planner->map.add_feature (feature->tag, feature->value, (feature->start == 0 && feature->end == (unsigned int) -1));
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}
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}
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static void
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hb_ot_shape_setup_masks (hb_ot_shape_context_t *c)
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{
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hb_mask_t global_mask = c->plan->map.get_global_mask ();
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c->buffer->reset_masks (global_mask);
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hb_ot_shape_complex_setup_masks (c->plan->shaper, &c->plan->map, c->buffer);
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for (unsigned int i = 0; i < c->num_user_features; i++)
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{
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const hb_feature_t *feature = &c->user_features[i];
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if (!(feature->start == 0 && feature->end == (unsigned int)-1)) {
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unsigned int shift;
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hb_mask_t mask = c->plan->map.get_mask (feature->tag, &shift);
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c->buffer->set_masks (feature->value << shift, mask, feature->start, feature->end);
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}
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}
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}
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/* Main shaper */
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/* Prepare */
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void
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_hb_set_unicode_props (hb_buffer_t *buffer)
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{
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unsigned int count = buffer->len;
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for (unsigned int i = 1; i < count; i++)
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hb_glyph_info_set_unicode_props (&buffer->info[i], buffer->unicode);
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}
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static void
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hb_form_clusters (hb_buffer_t *buffer)
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{
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unsigned int count = buffer->len;
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for (unsigned int i = 1; i < count; i++)
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if (FLAG (buffer->info[i].general_category()) &
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(FLAG (HB_UNICODE_GENERAL_CATEGORY_SPACING_MARK) |
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FLAG (HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) |
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FLAG (HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)))
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buffer->info[i].cluster = buffer->info[i - 1].cluster;
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}
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static void
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hb_ensure_native_direction (hb_buffer_t *buffer)
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{
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hb_direction_t direction = buffer->props.direction;
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/* TODO vertical:
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* The only BTT vertical script is Ogham, but it's not clear to me whether OpenType
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* Ogham fonts are supposed to be implemented BTT or not. Need to research that
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* first. */
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if ((HB_DIRECTION_IS_HORIZONTAL (direction) && direction != hb_script_get_horizontal_direction (buffer->props.script)) ||
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(HB_DIRECTION_IS_VERTICAL (direction) && direction != HB_DIRECTION_TTB))
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{
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hb_buffer_reverse_clusters (buffer);
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buffer->props.direction = HB_DIRECTION_REVERSE (buffer->props.direction);
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}
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}
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/* Substitute */
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static void
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hb_mirror_chars (hb_ot_shape_context_t *c)
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{
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hb_unicode_funcs_t *unicode = c->buffer->unicode;
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if (HB_DIRECTION_IS_FORWARD (c->target_direction))
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return;
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hb_mask_t rtlm_mask = c->plan->map.get_1_mask (HB_TAG ('r','t','l','m'));
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unsigned int count = c->buffer->len;
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for (unsigned int i = 0; i < count; i++) {
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hb_codepoint_t codepoint = hb_unicode_mirroring (unicode, c->buffer->info[i].codepoint);
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if (likely (codepoint == c->buffer->info[i].codepoint))
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c->buffer->info[i].mask |= rtlm_mask; /* XXX this should be moved to before setting user-feature masks */
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else
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c->buffer->info[i].codepoint = codepoint;
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}
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}
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static void
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hb_map_glyphs (hb_font_t *font,
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hb_buffer_t *buffer)
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{
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hb_codepoint_t glyph;
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if (unlikely (!buffer->len))
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return;
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buffer->clear_output ();
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unsigned int count = buffer->len - 1;
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for (buffer->idx = 0; buffer->idx < count;) {
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if (unlikely (is_variation_selector (buffer->info[buffer->idx + 1].codepoint))) {
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hb_font_get_glyph (font, buffer->info[buffer->idx].codepoint, buffer->info[buffer->idx + 1].codepoint, &glyph);
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buffer->replace_glyph (glyph);
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buffer->skip_glyph ();
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} else {
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hb_font_get_glyph (font, buffer->info[buffer->idx].codepoint, 0, &glyph);
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buffer->replace_glyph (glyph);
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}
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}
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if (likely (buffer->idx < buffer->len)) {
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hb_font_get_glyph (font, buffer->info[buffer->idx].codepoint, 0, &glyph);
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buffer->replace_glyph (glyph);
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}
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buffer->swap_buffers ();
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}
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static void
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hb_substitute_default (hb_ot_shape_context_t *c)
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{
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hb_ot_layout_substitute_start (c->buffer);
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hb_mirror_chars (c);
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hb_map_glyphs (c->font, c->buffer);
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}
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static void
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hb_ot_substitute_complex (hb_ot_shape_context_t *c)
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{
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if (hb_ot_layout_has_substitution (c->face)) {
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c->plan->map.substitute (c->face, c->buffer);
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c->applied_substitute_complex = TRUE;
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}
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hb_ot_layout_substitute_finish (c->buffer);
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return;
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}
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static void
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hb_substitute_complex_fallback (hb_ot_shape_context_t *c HB_UNUSED)
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{
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/* TODO Arabic */
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}
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/* Position */
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static void
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hb_position_default (hb_ot_shape_context_t *c)
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{
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hb_ot_layout_position_start (c->buffer);
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unsigned int count = c->buffer->len;
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for (unsigned int i = 0; i < count; i++) {
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hb_font_get_glyph_advance_for_direction (c->font, c->buffer->info[i].codepoint,
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c->buffer->props.direction,
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&c->buffer->pos[i].x_advance,
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&c->buffer->pos[i].y_advance);
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hb_font_subtract_glyph_origin_for_direction (c->font, c->buffer->info[i].codepoint,
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c->buffer->props.direction,
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&c->buffer->pos[i].x_offset,
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&c->buffer->pos[i].y_offset);
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}
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}
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static void
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hb_ot_position_complex (hb_ot_shape_context_t *c)
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{
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if (hb_ot_layout_has_positioning (c->face))
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{
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/* Change glyph origin to what GPOS expects, apply GPOS, change it back. */
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unsigned int count = c->buffer->len;
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for (unsigned int i = 0; i < count; i++) {
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hb_font_add_glyph_origin_for_direction (c->font, c->buffer->info[i].codepoint,
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HB_DIRECTION_LTR,
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&c->buffer->pos[i].x_offset,
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&c->buffer->pos[i].y_offset);
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}
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c->plan->map.position (c->font, c->buffer);
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for (unsigned int i = 0; i < count; i++) {
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hb_font_subtract_glyph_origin_for_direction (c->font, c->buffer->info[i].codepoint,
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HB_DIRECTION_LTR,
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&c->buffer->pos[i].x_offset,
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&c->buffer->pos[i].y_offset);
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}
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c->applied_position_complex = TRUE;
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}
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hb_ot_layout_position_finish (c->buffer);
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return;
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}
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static void
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hb_position_complex_fallback (hb_ot_shape_context_t *c HB_UNUSED)
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{
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/* TODO Mark pos */
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}
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static void
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hb_truetype_kern (hb_ot_shape_context_t *c)
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{
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/* TODO Check for kern=0 */
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unsigned int count = c->buffer->len;
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for (unsigned int i = 1; i < count; i++) {
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hb_position_t x_kern, y_kern, kern1, kern2;
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hb_font_get_glyph_kerning_for_direction (c->font,
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c->buffer->info[i - 1].codepoint, c->buffer->info[i].codepoint,
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c->buffer->props.direction,
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&x_kern, &y_kern);
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kern1 = x_kern >> 1;
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kern2 = x_kern - kern1;
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c->buffer->pos[i - 1].x_advance += kern1;
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c->buffer->pos[i].x_advance += kern2;
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c->buffer->pos[i].x_offset += kern2;
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kern1 = y_kern >> 1;
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kern2 = y_kern - kern1;
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c->buffer->pos[i - 1].y_advance += kern1;
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c->buffer->pos[i].y_advance += kern2;
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c->buffer->pos[i].y_offset += kern2;
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}
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}
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static void
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hb_position_complex_fallback_visual (hb_ot_shape_context_t *c)
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{
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hb_truetype_kern (c);
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}
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/* Do it! */
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static void
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hb_ot_shape_execute_internal (hb_ot_shape_context_t *c)
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{
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c->buffer->deallocate_var_all ();
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/* Save the original direction, we use it later. */
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c->target_direction = c->buffer->props.direction;
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HB_BUFFER_ALLOCATE_VAR (c->buffer, general_category);
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HB_BUFFER_ALLOCATE_VAR (c->buffer, combining_class);
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_hb_set_unicode_props (c->buffer); /* BUFFER: Set general_category and combining_class */
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hb_form_clusters (c->buffer);
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hb_ensure_native_direction (c->buffer);
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_hb_ot_shape_normalize (c);
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hb_ot_shape_setup_masks (c);
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/* SUBSTITUTE */
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{
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hb_substitute_default (c);
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hb_ot_substitute_complex (c);
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if (!c->applied_substitute_complex)
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hb_substitute_complex_fallback (c);
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}
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/* POSITION */
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{
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hb_position_default (c);
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hb_ot_position_complex (c);
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hb_bool_t position_fallback = !c->applied_position_complex;
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if (position_fallback)
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hb_position_complex_fallback (c);
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if (HB_DIRECTION_IS_BACKWARD (c->buffer->props.direction))
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hb_buffer_reverse (c->buffer);
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if (position_fallback)
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hb_position_complex_fallback_visual (c);
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}
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HB_BUFFER_DEALLOCATE_VAR (c->buffer, combining_class);
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HB_BUFFER_DEALLOCATE_VAR (c->buffer, general_category);
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c->buffer->props.direction = c->target_direction;
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c->buffer->deallocate_var_all ();
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}
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static void
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hb_ot_shape_plan_internal (hb_ot_shape_plan_t *plan,
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hb_face_t *face,
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const hb_segment_properties_t *props,
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const hb_feature_t *user_features,
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unsigned int num_user_features)
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{
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hb_ot_shape_planner_t planner;
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planner.shaper = hb_ot_shape_complex_categorize (props);
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hb_ot_shape_collect_features (&planner, props, user_features, num_user_features);
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planner.compile (face, props, *plan);
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}
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static void
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hb_ot_shape_execute (hb_ot_shape_plan_t *plan,
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hb_font_t *font,
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hb_buffer_t *buffer,
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const hb_feature_t *user_features,
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unsigned int num_user_features)
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{
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hb_ot_shape_context_t c = {plan, font, font->face, buffer, user_features, num_user_features};
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hb_ot_shape_execute_internal (&c);
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}
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hb_bool_t
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hb_ot_shape (hb_font_t *font,
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hb_buffer_t *buffer,
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const hb_feature_t *features,
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unsigned int num_features,
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const char * const *shaper_options)
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{
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hb_ot_shape_plan_t plan;
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buffer->guess_properties ();
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hb_ot_shape_plan_internal (&plan, font->face, &buffer->props, features, num_features);
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hb_ot_shape_execute (&plan, font, buffer, features, num_features);
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return TRUE;
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}
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