1 files changed, 49 insertions, 24 deletions

diff --git a/src/3rdparty/harfbuzz-ng/src/hb-ot-shape-fallback.cc b/src/3rdparty/harfbuzz-ng/src/hb-ot-shape-fallback.cc
index 284d030d5f..449b64e5ca 100644
--- a/src/3rdparty/harfbuzz-ng/src/hb-ot-shape-fallback.cc
+++ b/src/3rdparty/harfbuzz-ng/src/hb-ot-shape-fallback.cc
@@ -260,7 +260,13 @@ position_mark (const hb_ot_shape_plan_t *plan,
 
     case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW_LEFT:
     case HB_UNICODE_COMBINING_CLASS_ATTACHED_BELOW:
-      pos.y_offset += base_extents.y_bearing + base_extents.height - mark_extents.y_bearing;
+      pos.y_offset = base_extents.y_bearing + base_extents.height - mark_extents.y_bearing;
+      /* Never shift up "below" marks. */
+      if ((y_gap > 0) == (pos.y_offset > 0))
+      {
+	base_extents.height -= pos.y_offset;
+	pos.y_offset = 0;
+      }
       base_extents.height += mark_extents.height;
       break;
 
@@ -274,7 +280,15 @@ position_mark (const hb_ot_shape_plan_t *plan,
 
     case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE:
     case HB_UNICODE_COMBINING_CLASS_ATTACHED_ABOVE_RIGHT:
-      pos.y_offset += base_extents.y_bearing - (mark_extents.y_bearing + mark_extents.height);
+      pos.y_offset = base_extents.y_bearing - (mark_extents.y_bearing + mark_extents.height);
+      /* Don't shift down "above" marks too much. */
+      if ((y_gap > 0) != (pos.y_offset > 0))
+      {
+	unsigned int correction = -pos.y_offset / 2;
+	base_extents.y_bearing += correction;
+	base_extents.height -= correction;
+	pos.y_offset += correction;
+      }
       base_extents.y_bearing -= mark_extents.height;
       base_extents.height += mark_extents.height;
       break;
@@ -300,8 +314,8 @@ 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;
 
-  unsigned int lig_id = get_lig_id (buffer->info[base]);
-  unsigned int num_lig_components = get_lig_num_comps (buffer->info[base]);
+  unsigned int lig_id = _hb_glyph_info_get_lig_id (&buffer->info[base]);
+  unsigned int num_lig_components = _hb_glyph_info_get_lig_num_comps (&buffer->info[base]);
 
   hb_position_t x_offset = 0, y_offset = 0;
   if (HB_DIRECTION_IS_FORWARD (buffer->props.direction)) {
@@ -317,8 +331,8 @@ position_around_base (const hb_ot_shape_plan_t *plan,
     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;
+	unsigned int this_lig_id = _hb_glyph_info_get_lig_id (&buffer->info[i]);
+	unsigned int this_lig_component = _hb_glyph_info_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;
@@ -416,41 +430,52 @@ _hb_ot_shape_fallback_kern (const hb_ot_shape_plan_t *plan,
 			    hb_font_t *font,
 			    hb_buffer_t  *buffer)
 {
-  unsigned int count = buffer->len;
   hb_mask_t kern_mask = plan->map.get_1_mask (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction) ?
 					      HB_TAG ('k','e','r','n') : HB_TAG ('v','k','r','n'));
+  if (!kern_mask) return;
+
+  unsigned int count = buffer->len;
 
   OT::hb_apply_context_t c (1, font, buffer);
   c.set_lookup_mask (kern_mask);
   c.set_lookup_props (OT::LookupFlag::IgnoreMarks);
 
-  for (buffer->idx = 0; buffer->idx < count;)
+  hb_glyph_info_t *info = buffer->info;
+  hb_glyph_position_t *pos = buffer->pos;
+
+  for (unsigned int idx = 0; idx < count;)
   {
-    OT::hb_apply_context_t::skipping_forward_iterator_t skippy_iter (&c, buffer->idx, 1);
+    OT::hb_apply_context_t::skipping_forward_iterator_t skippy_iter (&c, idx, 1);
     if (!skippy_iter.next ())
     {
-      buffer->idx++;
+      idx++;
       continue;
     }
 
-    hb_position_t x_kern, y_kern, kern1, kern2;
-    font->get_glyph_kerning_for_direction (buffer->info[buffer->idx].codepoint,
-					   buffer->info[skippy_iter.idx].codepoint,
+    hb_position_t x_kern, y_kern;
+    font->get_glyph_kerning_for_direction (info[idx].codepoint,
+					   info[skippy_iter.idx].codepoint,
 					   buffer->props.direction,
 					   &x_kern, &y_kern);
 
-    kern1 = x_kern >> 1;
-    kern2 = x_kern - kern1;
-    buffer->pos[buffer->idx].x_advance += kern1;
-    buffer->pos[skippy_iter.idx].x_advance += kern2;
-    buffer->pos[skippy_iter.idx].x_offset += kern2;
+    if (x_kern)
+    {
+      hb_position_t kern1 = x_kern >> 1;
+      hb_position_t kern2 = x_kern - kern1;
+      pos[idx].x_advance += kern1;
+      pos[skippy_iter.idx].x_advance += kern2;
+      pos[skippy_iter.idx].x_offset += kern2;
+    }
 
-    kern1 = y_kern >> 1;
-    kern2 = y_kern - kern1;
-    buffer->pos[buffer->idx].y_advance += kern1;
-    buffer->pos[skippy_iter.idx].y_advance += kern2;
-    buffer->pos[skippy_iter.idx].y_offset += kern2;
+    if (y_kern)
+    {
+      hb_position_t kern1 = y_kern >> 1;
+      hb_position_t kern2 = y_kern - kern1;
+      pos[idx].y_advance += kern1;
+      pos[skippy_iter.idx].y_advance += kern2;
+      pos[skippy_iter.idx].y_offset += kern2;
+    }
 
-    buffer->idx = skippy_iter.idx;
+    idx = skippy_iter.idx;
   }
 }