From f67917161bbe317a33d6407fbc62ebffcafe7154 Mon Sep 17 00:00:00 2001 From: Behdad Esfahbod Date: Thu, 6 Sep 2012 17:22:31 -0400 Subject: [PATCH] [OT] Do per-ligature-component fallback mark positioning With this in place, you can remove GDEF/GSUB/GPOS tables from Arabic fonts and still get per-component marks positioned on oh-yeah-fallback-formed LAM-ALEF ligatures with marks in between the LAM and ALEF. Now *that*'s pretty cool, if a bit anachronistic... --- src/hb-ot-shape-fallback.cc | 43 ++++++++++++++++++++++++++++++++++++------- 1 file changed, 36 insertions(+), 7 deletions(-) diff --git a/src/hb-ot-shape-fallback.cc b/src/hb-ot-shape-fallback.cc index a532e20..eb7777e 100644 --- a/src/hb-ot-shape-fallback.cc +++ b/src/hb-ot-shape-fallback.cc @@ -287,6 +287,7 @@ position_around_base (const hb_ot_shape_plan_t *plan, unsigned int base, unsigned int end) { + hb_direction_t horiz_dir = HB_DIRECTION_INVALID; hb_glyph_extents_t base_extents; if (!font->get_glyph_extents (buffer->info[base].codepoint, &base_extents)) @@ -298,22 +299,53 @@ position_around_base (const hb_ot_shape_plan_t *plan, base_extents.x_bearing += buffer->pos[base].x_offset; base_extents.y_bearing += buffer->pos[base].y_offset; - /* XXX Handle ligature component positioning... */ - HB_UNUSED bool is_ligature = is_a_ligature (buffer->info[base]); + unsigned int lig_id = get_lig_id (buffer->info[base]); + unsigned int num_lig_components = get_lig_num_comps (buffer->info[base]); hb_position_t x_offset = 0, y_offset = 0; if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) { x_offset -= buffer->pos[base].x_advance; y_offset -= buffer->pos[base].y_advance; } + + hb_glyph_extents_t component_extents = base_extents; + unsigned int last_lig_component = (unsigned int) -1; unsigned int last_combining_class = 255; hb_glyph_extents_t cluster_extents; for (unsigned int i = base + 1; i < end; i++) if (_hb_glyph_info_get_modified_combining_class (&buffer->info[i])) { + if (num_lig_components > 1) { + unsigned int this_lig_id = get_lig_id (buffer->info[i]); + unsigned int this_lig_component = get_lig_comp (buffer->info[i]) - 1; + /* Conditions for attaching to the last component. */ + if (!lig_id || lig_id != this_lig_id || this_lig_component >= num_lig_components) + this_lig_component = num_lig_components - 1; + if (last_lig_component != this_lig_component) + { + last_lig_component = this_lig_component; + last_combining_class = 255; + component_extents = base_extents; + if (unlikely (horiz_dir == HB_DIRECTION_INVALID)) { + if (HB_DIRECTION_IS_HORIZONTAL (plan->props.direction)) + horiz_dir = plan->props.direction; + else + horiz_dir = hb_script_get_horizontal_direction (plan->props.script); + } + if (horiz_dir == HB_DIRECTION_LTR) + component_extents.x_bearing += (this_lig_component * component_extents.width) / num_lig_components; + else + component_extents.x_bearing += ((num_lig_components - 1 - this_lig_component) * component_extents.width) / num_lig_components; + component_extents.width /= num_lig_components; + } + } + unsigned int this_combining_class = _hb_glyph_info_get_modified_combining_class (&buffer->info[i]); - if (this_combining_class != last_combining_class) - cluster_extents = base_extents; + if (last_combining_class != this_combining_class) + { + last_combining_class = this_combining_class; + cluster_extents = component_extents; + } position_mark (plan, font, buffer, cluster_extents, i, this_combining_class); @@ -322,7 +354,6 @@ position_around_base (const hb_ot_shape_plan_t *plan, buffer->pos[i].x_offset += x_offset; buffer->pos[i].y_offset += y_offset; - last_combining_class = this_combining_class; } else { if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) { x_offset -= buffer->pos[i].x_advance; @@ -332,8 +363,6 @@ position_around_base (const hb_ot_shape_plan_t *plan, y_offset += buffer->pos[i].y_advance; } } - - } static inline void -- 2.7.4