[otfallback] Don't shift down above-marks too much
This seems to generate much better, almost-perfect, positioning for
Arabic as well as Latin above marks.
diff --git a/src/hb-ot-shape-fallback.cc b/src/hb-ot-shape-fallback.cc
index 2af924e..593c333 100644
--- a/src/hb-ot-shape-fallback.cc
+++ b/src/hb-ot-shape-fallback.cc
@@ -261,7 +261,7 @@
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;
- /* Never shift a "below" mark upwards. */
+ /* Never shift up "below" marks. */
if ((y_gap > 0) == (pos.y_offset > 0))
{
base_extents.height -= pos.y_offset;
@@ -281,6 +281,14 @@
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);
+ /* 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;
