[coretext] Use CFRunStatus
Assert that all runs had expected direction, and take hint for
non-monotone clusters.
diff --git a/src/hb-coretext.cc b/src/hb-coretext.cc
index 8081bfc..8caff48 100644
--- a/src/hb-coretext.cc
+++ b/src/hb-coretext.cc
@@ -740,12 +740,17 @@
unsigned int num_runs = CFArrayGetCount (glyph_runs);
buffer->len = 0;
+ uint32_t status_and = ~0, status_or = 0;
const CFRange range_all = CFRangeMake (0, 0);
for (unsigned int i = 0; i < num_runs; i++)
{
CTRunRef run = static_cast<CTRunRef>(CFArrayGetValueAtIndex (glyph_runs, i));
+ CTRunStatus run_status = CTRunGetStatus (run);
+ status_or |= run_status;
+ status_and &= run_status;
+ DEBUG_MSG (CORETEXT, run, "CTRunStatus: %x", run_status);
/* CoreText does automatic font fallback (AKA "cascading") for characters
* not supported by the requested font, and provides no way to turn it off,
@@ -863,6 +868,11 @@
}
}
+ /* Make sure all runs had the expected direction. */
+ bool backward = HB_DIRECTION_IS_BACKWARD (buffer->props.direction);
+ assert (bool (status_and & kCTRunStatusRightToLeft) == backward);
+ assert (bool (status_or & kCTRunStatusRightToLeft) == backward);
+
buffer->clear_positions ();
unsigned int count = buffer->len;
@@ -878,12 +888,15 @@
/* Fix up clusters so that we never return out-of-order indices;
* if core text has reordered glyphs, we'll merge them to the
- * beginning of the reordered cluster.
+ * beginning of the reordered cluster. CoreText is nice enough
+ * to tell us whenever it has produced nonmonotonic results...
+ * Note that we assume the input clusters were nonmonotonic to
+ * begin with.
*
* This does *not* mean we'll form the same clusters as Uniscribe
* or the native OT backend, only that the cluster indices will be
* monotonic in the output buffer. */
- if (count > 1)
+ if (count > 1 && (status_or & kCTRunStatusNonMonotonic))
{
hb_glyph_info_t *info = buffer->info;
if (HB_DIRECTION_IS_FORWARD (buffer->props.direction))
