[arabic/stch] Also work in left-to-right direction
Fixes https://github.com/harfbuzz/harfbuzz/issues/4369
diff --git a/src/hb-ot-shaper-arabic.cc b/src/hb-ot-shaper-arabic.cc
index 12c7da2..1bd730b 100644
--- a/src/hb-ot-shaper-arabic.cc
+++ b/src/hb-ot-shaper-arabic.cc
@@ -486,8 +486,10 @@
if (likely (!(buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH)))
return;
- /* The Arabic shaper currently always processes in RTL mode, so we should
- * stretch / position the stretched pieces to the left / preceding glyphs. */
+ bool rtl = buffer->props.direction == HB_DIRECTION_RTL;
+
+ if (!rtl)
+ buffer->reverse ();
/* We do a two pass implementation:
* First pass calculates the exact number of extra glyphs we need,
@@ -602,14 +604,24 @@
pos[k - 1].x_advance = 0;
for (unsigned int n = 0; n < repeat; n++)
{
- x_offset -= width;
- if (n > 0)
- x_offset += extra_repeat_overlap;
+ if (rtl)
+ {
+ x_offset -= width;
+ if (n > 0)
+ x_offset += extra_repeat_overlap;
+ }
pos[k - 1].x_offset = x_offset;
/* Append copy. */
--j;
info[j] = info[k - 1];
pos[j] = pos[k - 1];
+
+ if (!rtl)
+ {
+ x_offset += width;
+ if (n > 0)
+ x_offset -= extra_repeat_overlap;
+ }
}
}
}
@@ -626,6 +638,9 @@
buffer->len = new_len;
}
}
+
+ if (!rtl)
+ buffer->reverse ();
}
