gstate: Degenerate font drawing is a noopwip/0matrix

Instead of passing a size 0 (or degenerate in any other way) font to
the backend, handle the operation in gstate.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/cairo-gstate.c b/src/cairo-gstate.c
index eaf7a56aa..6cab358da 100644
--- a/src/cairo-gstate.c
+++ b/src/cairo-gstate.c
@@ -1911,6 +1911,18 @@ _cairo_gstate_show_text_glyphs (cairo_gstate_t		   *gstate,
     if (unlikely (status))
 	return status;
 
+    if (_cairo_matrix_compute_determinant (&gstate->scaled_font->scale) == 0) {
+	if (_cairo_operator_bounded_by_mask (gstate->op))
+	    return CAIRO_STATUS_SUCCESS;
+
+	pattern = &_cairo_pattern_clear.base;
+	status = _cairo_surface_paint (gstate->target,
+				       CAIRO_OPERATOR_CLEAR, pattern,
+				       _gstate_get_clip (gstate, &clip));
+	_cairo_clip_fini (&clip);
+	return status;
+    }
+
     transformed_glyphs = stack_transformed_glyphs;
     transformed_clusters = stack_transformed_clusters;