From 539ca68c7725f9d7bfb6ba8ad3c94f354a6c1142 Mon Sep 17 00:00:00 2001 From: Matthias Clasen Date: Thu, 17 Feb 2022 13:08:09 -0600 Subject: layout: Handle baselines During post-processing for lines, take into account the baselines for each run, and shift them vertically to align them on the dominant baseline. --- pango/pango-layout.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 64 insertions(+), 2 deletions(-) diff --git a/pango/pango-layout.c b/pango/pango-layout.c index 9167883c..6e4bb357 100644 --- a/pango/pango-layout.c +++ b/pango/pango-layout.c @@ -85,6 +85,7 @@ #include #include +#include #include "pango-layout-private.h" #include "pango-attributes-private.h" @@ -6694,6 +6695,12 @@ apply_baseline_shift (PangoLayoutLine *line, { int y_offset = 0; PangoItem *prev = NULL; + hb_position_t baseline_adjustment = 0; +#if HB_VERSION_ATLEAST(4,0,0) + hb_ot_layout_baseline_tag_t baseline_tag = 0; + hb_position_t baseline; + hb_position_t run_baseline; +#endif for (GSList *l = line->runs; l; l = l->next) { @@ -6701,16 +6708,71 @@ apply_baseline_shift (PangoLayoutLine *line, PangoItem *item = run->item; int start_x_offset, end_x_offset; int start_y_offset, end_y_offset; +#if HB_VERSION_ATLEAST(4,0,0) + hb_font_t *hb_font; + hb_script_t script; + hb_language_t language; + hb_direction_t direction; + hb_tag_t script_tags[HB_OT_MAX_TAGS_PER_SCRIPT]; + hb_tag_t lang_tags[HB_OT_MAX_TAGS_PER_LANGUAGE]; + unsigned int script_count = HB_OT_MAX_TAGS_PER_SCRIPT; + unsigned int lang_count = HB_OT_MAX_TAGS_PER_LANGUAGE; + + hb_font = pango_font_get_hb_font (item->analysis.font); + + script = hb_glib_script_to_script (item->analysis.script); + language = hb_language_from_string (pango_language_to_string (item->analysis.language), -1); + hb_ot_tags_from_script_and_language (script, language, + &script_count, script_tags, + &lang_count, lang_tags); + + if (item->analysis.flags & PANGO_ANALYSIS_FLAG_CENTERED_BASELINE) + direction = HB_DIRECTION_TTB; + else + direction = HB_DIRECTION_LTR; + + if (baseline_tag == 0) + { + if (item->analysis.flags & PANGO_ANALYSIS_FLAG_CENTERED_BASELINE) + baseline_tag = HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_CENTRAL; + else + baseline_tag = hb_ot_layout_get_horizontal_baseline_tag_for_script (script); + hb_ot_layout_get_baseline_with_fallback (hb_font, + baseline_tag, + direction, + script_tags[script_count - 1], + lang_count ? lang_tags[lang_count - 1] : HB_TAG_NONE, + &run_baseline); + baseline = run_baseline; + } + else + { + hb_ot_layout_get_baseline_with_fallback (hb_font, + baseline_tag, + direction, + script_tags[script_count - 1], + lang_count ? lang_tags[lang_count - 1] : HB_TAG_NONE, + &run_baseline); + } + + /* Don't do baseline adjustment in vertical, since the renderer + * is still doing its own baseline shifting there + */ + if (item->analysis.flags & PANGO_ANALYSIS_FLAG_CENTERED_BASELINE) + baseline_adjustment = 0; + else + baseline_adjustment = baseline - run_baseline; +#endif collect_baseline_shift (state, item, prev, &start_x_offset, &start_y_offset, &end_x_offset, &end_y_offset); - y_offset += start_y_offset; + y_offset += start_y_offset + baseline_adjustment; run->y_offset = y_offset; run->start_x_offset = start_x_offset; run->end_x_offset = end_x_offset; - y_offset += end_y_offset; + y_offset += end_y_offset - baseline_adjustment; prev = item; } -- cgit v1.2.1