cssimage: Warn if gradients only have 1 color stop

GTK <= 3.20 allowed that but the CSS spec and borwsers do not.
We might want to just remove that feature, but for now, we just warn.

1 files changed, 8 insertions, 0 deletions

diff --git a/gtk/gtkcssimageradial.c b/gtk/gtkcssimageradial.c
index bc137db7da..81967c9a80 100644
--- a/gtk/gtkcssimageradial.c
+++ b/gtk/gtkcssimageradial.c
@@ -377,6 +377,14 @@ gtk_css_image_radial_parse (GtkCssImage  *image,
 
   } while (_gtk_css_parser_try (parser, ",", TRUE));
 
+  if (radial->stops->len < 2)
+    {
+      _gtk_css_parser_error_full (parser,
+                                  GTK_CSS_PROVIDER_ERROR_DEPRECATED,
+                                  "Using one color stop with %s() is deprecated.",
+                                  radial->repeating ? "repeating-radial-gradient" : "radial-gradient");
+    }
+
   if (!_gtk_css_parser_try (parser, ")", TRUE))
     {
       _gtk_css_parser_error (parser, "Missing closing bracket at end of radial gradient");