[trak] Only adjust around first glyph

Assumes graphemes only have one base glyph.

diff --git a/src/hb-aat-layout-trak-table.hh b/src/hb-aat-layout-trak-table.hh
index 71f169c..dbad449 100644 (file)
--- a/src/hb-aat-layout-trak-table.hh
+++ b/src/hb-aat-layout-trak-table.hh
@@ -174,24 +174,24 @@ struct trak
     {
       const TrackData &trackData = this+horizData;
       float tracking = trackData.get_tracking (this, ptem);
-      hb_position_t advance_to_add = c->font->em_scalef_x (tracking / 2);
+      hb_position_t offset_to_add = c->font->em_scalef_x (tracking / 2);
+      hb_position_t advance_to_add = c->font->em_scalef_x (tracking);
       foreach_grapheme (buffer, start, end)
       {
-       buffer->pos[start].x_offset += advance_to_add;
        buffer->pos[start].x_advance += advance_to_add;
-       buffer->pos[end].x_advance += advance_to_add;
+       buffer->pos[start].x_offset += offset_to_add;
       }
     }
     else
     {
       const TrackData &trackData = this+vertData;
       float tracking = trackData.get_tracking (this, ptem);
-      hb_position_t advance_to_add = c->font->em_scalef_y (tracking / 2);
+      hb_position_t offset_to_add = c->font->em_scalef_y (tracking / 2);
+      hb_position_t advance_to_add = c->font->em_scalef_y (tracking);
       foreach_grapheme (buffer, start, end)
       {
-       buffer->pos[start].y_offset += advance_to_add;
        buffer->pos[start].y_advance += advance_to_add;
-       buffer->pos[end].y_advance += advance_to_add;
+       buffer->pos[start].y_offset += offset_to_add;
       }
     }