_cairo_scaled_font_init: Detect an invalid matrix and return an error.

Also fix all callers to notice and propagate the error, (though
some paths will still lose the CAIRO_STATUS_INVALID_MATRIX value
due to a return value of NULL at one point).

3 files changed, 30 insertions, 13 deletions

diff --git a/src/cairo-atsui-font.c b/src/cairo-atsui-font.c
index 8aca2076d..92d38f248 100644
--- a/src/cairo-atsui-font.c
+++ b/src/cairo-atsui-font.c
@@ -230,8 +230,13 @@ _cairo_atsui_font_create_scaled (cairo_font_face_t *font_face,
     if (font == NULL)
 	return CAIRO_STATUS_NO_MEMORY;
 
-    _cairo_scaled_font_init(&font->base, font_face, font_matrix, ctm, options,
-			    &cairo_atsui_scaled_font_backend);
+    status = _cairo_scaled_font_init (&font->base,
+				      font_face, font_matrix, ctm, options,
+				      &cairo_atsui_scaled_font_backend);
+    if (status) {
+	free (font);
+	return status;
+    }
 
     _cairo_matrix_compute_scale_factors (&font->base.scale, 
 					 &xscale, &yscale, 1);
diff --git a/src/cairo-scaled-font.c b/src/cairo-scaled-font.c
index 6b51e7f0c..954a4a4ba 100644
--- a/src/cairo-scaled-font.c
+++ b/src/cairo-scaled-font.c
@@ -351,6 +351,23 @@ _cairo_scaled_font_init (cairo_scaled_font_t               *scaled_font,
 			 const cairo_font_options_t	   *options,
 			 const cairo_scaled_font_backend_t *backend)
 {
+    cairo_matrix_t inverse;
+    cairo_status_t status;
+
+    /* Initialize scaled_font->scale early for easier bail out on an
+     * invalid matrix. */
+    _cairo_scaled_font_init_key (scaled_font, font_face,
+				 font_matrix, ctm, options);
+
+    cairo_matrix_multiply (&scaled_font->scale,
+			   &scaled_font->font_matrix,
+			   &scaled_font->ctm);
+
+    inverse = scaled_font->scale;
+    status = cairo_matrix_invert (&inverse);
+    if (status)
+	return status;
+
     scaled_font->glyphs = _cairo_cache_create (_cairo_scaled_glyph_keys_equal,
 					       _cairo_scaled_glyph_destroy,
 					       max_glyphs_cached_per_font);
@@ -361,15 +378,8 @@ _cairo_scaled_font_init (cairo_scaled_font_t               *scaled_font,
 
     _cairo_user_data_array_init (&scaled_font->user_data);
 
-    _cairo_scaled_font_init_key (scaled_font, font_face,
-				 font_matrix, ctm, options);
-
     cairo_font_face_reference (font_face);
 
-    cairo_matrix_multiply (&scaled_font->scale,
-			   &scaled_font->font_matrix,
-			   &scaled_font->ctm);
-
     CAIRO_MUTEX_INIT (&scaled_font->mutex);
 
     scaled_font->surface_backend = NULL;
diff --git a/src/cairo-win32-font.c b/src/cairo-win32-font.c
index 82e3bfcf8..e1f263b67 100644
--- a/src/cairo-win32-font.c
+++ b/src/cairo-win32-font.c
@@ -283,11 +283,13 @@ _win32_scaled_font_create (LOGFONTW                   *logfont,
     cairo_matrix_multiply (&scale, font_matrix, ctm);
     _compute_transform (f, &scale);
 
-    _cairo_scaled_font_init (&f->base, font_face,
-			     font_matrix, ctm, options,
-			     &cairo_win32_scaled_font_backend);
+    status = _cairo_scaled_font_init (&f->base, font_face,
+				      font_matrix, ctm, options,
+				      &cairo_win32_scaled_font_backend);
+
+    if (status == CAIRO_STATUS_SUCCESS)
+	status = _cairo_win32_scaled_font_set_metrics (f);
 
-    status = _cairo_win32_scaled_font_set_metrics (f);
     if (status) {
 	cairo_scaled_font_destroy (&f->base);
 	return NULL;