[gimp] app: in propgui, use flat color buttons for rgb props with no alpha

[N/A <ell src gnome org>]

commit bcb7545fe100db3a25e61319a1833bedffb8a6ea
Author: Ell <ell_se yahoo com>
Date:   Thu Nov 2 13:50:17 2017 -0400

    app: in propgui, use flat color buttons for rgb props with no alpha

 app/propgui/gimppropgui.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/app/propgui/gimppropgui.c b/app/propgui/gimppropgui.c
index 586c176..6ea9218 100644
--- a/app/propgui/gimppropgui.c
+++ b/app/propgui/gimppropgui.c
@@ -345,14 +345,19 @@ gimp_prop_widget_new_from_pspec (GObject                  *config,
     }
   else if (GIMP_IS_PARAM_SPEC_RGB (pspec))
     {
+      gboolean   has_alpha;
       GtkWidget *button;
 
+      has_alpha = gimp_param_spec_rgb_has_alpha (pspec);
+
       widget = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 4);
 
       button = gimp_prop_color_button_new (config, pspec->name,
                                            g_param_spec_get_nick (pspec),
                                            128, 24,
-                                           GIMP_COLOR_AREA_SMALL_CHECKS);
+                                           has_alpha ?
+                                             GIMP_COLOR_AREA_SMALL_CHECKS :
+                                             GIMP_COLOR_AREA_FLAT);
       gimp_color_button_set_update (GIMP_COLOR_BUTTON (button), TRUE);
       gimp_color_panel_set_context (GIMP_COLOR_PANEL (button), context);
       gtk_box_pack_start (GTK_BOX (widget), button, TRUE, TRUE, 0);