Add hb_buffer_normalize_glyphs() and hb-shape --normalize-glyphs
This reorders glyphs within the cluster to a nominal order. This should
have no visible effect on the output, but helps with testing, for
getting the same hb-shape output for visually-equal glyphs for each
cluster.
diff --git a/src/hb-buffer.cc b/src/hb-buffer.cc
index 44571da..ec29659 100644
--- a/src/hb-buffer.cc
+++ b/src/hb-buffer.cc
@@ -887,3 +887,79 @@
}
+static int
+compare_info_codepoint (const hb_glyph_info_t *pa,
+ const hb_glyph_info_t *pb)
+{
+ return (int) pb->codepoint - (int) pa->codepoint;
+}
+
+static inline void
+normalize_glyphs_cluster (hb_buffer_t *buffer,
+ unsigned int start,
+ unsigned int end,
+ bool backward)
+{
+ hb_glyph_position_t *pos = buffer->pos;
+
+ /* Total cluster advance */
+ hb_position_t total_x_advance = 0, total_y_advance = 0;
+ for (unsigned int i = start; i < end; i++)
+ {
+ total_x_advance += pos[i].x_advance;
+ total_y_advance += pos[i].y_advance;
+ }
+
+ hb_position_t x_advance = 0, y_advance = 0;
+ for (unsigned int i = start; i < end; i++)
+ {
+ pos[i].x_offset += x_advance;
+ pos[i].y_offset += y_advance;
+
+ x_advance += pos[i].x_advance;
+ y_advance += pos[i].y_advance;
+
+ pos[i].x_advance = 0;
+ pos[i].y_advance = 0;
+ }
+
+ if (backward)
+ {
+ /* Transfer all cluster advance to the last glyph. */
+ pos[end - 1].x_advance = total_x_advance;
+ pos[end - 1].y_advance = total_y_advance;
+
+ hb_bubble_sort (buffer->info + start, end - start - 1, compare_info_codepoint, buffer->pos + start);
+ } else {
+ /* Transfer all cluster advance to the first glyph. */
+ pos[start].x_advance += total_x_advance;
+ pos[start].y_advance += total_y_advance;
+ for (unsigned int i = start + 1; i < end; i++) {
+ pos[i].x_offset -= total_x_advance;
+ pos[i].y_offset -= total_y_advance;
+ }
+ hb_bubble_sort (buffer->info + start + 1, end - start - 1, compare_info_codepoint, buffer->pos + start + 1);
+ }
+}
+
+void
+hb_buffer_normalize_glyphs (hb_buffer_t *buffer)
+{
+ assert (buffer->have_positions);
+ /* XXX assert (buffer->have_glyphs); */
+
+ bool backward = HB_DIRECTION_IS_BACKWARD (buffer->props.direction);
+
+ unsigned int count = buffer->len;
+ if (unlikely (!count)) return;
+ hb_glyph_info_t *info = buffer->info;
+
+ unsigned int start = 0;
+ unsigned int end;
+ for (end = start + 1; end < count; end++)
+ if (info[start].cluster != info[end].cluster) {
+ normalize_glyphs_cluster (buffer, start, end, backward);
+ start = end;
+ }
+ normalize_glyphs_cluster (buffer, start, end, backward);
+}
