TRACE_APPLY (this);
unsigned int count = substitute.len;
- /* TODO:
- * Testing shows that Uniscribe actually allows zero-len susbstitute,
- * which essentially deletes a glyph. We don't allow for now. It
- * can be confusing to the client since the cluster from the deleted
- * glyph won't be merged with any output cluster... Also, currently
- * buffer->move_to() makes assumptions about this too. Perhaps fix
- * in the future after figuring out what to do with the clusters.
- */
- if (unlikely (!count)) return_trace (false);
-
/* Special-case to make it in-place and not consider this
* as a "multiplied" substitution. */
if (unlikely (count == 1))
c->replace_glyph (substitute.array[0]);
return_trace (true);
}
+ /* Spec disallows this, but Uniscribe allows it.
+ * https://github.com/behdad/harfbuzz/issues/253 */
+ else if (unlikely (count == 0))
+ {
+ c->buffer->delete_glyph ();
+ return_trace (true);
+ }
unsigned int klass = _hb_glyph_info_is_ligature (&c->buffer->cur()) ?
HB_OT_LAYOUT_GLYPH_PROPS_BASE_GLYPH : 0;