[gimp/gimp-2-8] Bug 775646 - Levels Tool: handles difficult to read with dark theme.

[Jehan Pagès <jehanp src gnome org>]

commit 77d6969a9f12c50ea33dbeec8a15e4e754a5f611
Author: Jehan <jehan girinstud io>
Date:   Wed Dec 7 01:37:56 2016 +0100

    Bug 775646 - Levels Tool: handles difficult to read with dark theme.
    
    The white, gray and dark sliders of GimpHandleBar have a black contour.
    This makes the white and gray slider visible even with similar colored
    background. On the other hand, the black slider is barely visible on a
    dark background (and could even be made totally invisible using the same
    color). So let's use a light-gray contour on the dark slider, making now
    all sliders working with any background color.
    
    (cherry picked from commit afccaa91050910102b4da88e4cdd135d3d127241)

 app/widgets/gimphandlebar.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)
---
diff --git a/app/widgets/gimphandlebar.c b/app/widgets/gimphandlebar.c
index 5bfab70..9d6c2fa 100644
--- a/app/widgets/gimphandlebar.c
+++ b/app/widgets/gimphandlebar.c
@@ -199,7 +199,13 @@ gimp_handle_bar_expose (GtkWidget      *widget,
 
           cairo_fill_preserve (cr);
 
-          cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
+          /* Make all sliders well visible even on similar colored
+           * backgrounds.
+           */
+          if (i == 0)
+            cairo_set_source_rgb (cr, 0.6, 0.6, 0.6);
+          else
+            cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
 
           cairo_stroke (cr);
         }