[gimp/gimp-2-10] app: in GimpSmudge, avoid copying brush pixmap when flow = 0

[Ell <ell src gnome org>]

commit 86e97536d312ca2266f2a012d9401e20f0aa1c9b
Author: Ell <ell_se yahoo com>
Date:   Sun Feb 24 13:11:33 2019 -0500

    app: in GimpSmudge, avoid copying brush pixmap when flow = 0
    
    In GimpSmudge, avoid copying the brush's dab to the paint buffer
    when using a pixmap brush if the flow parameter is 0 -- it has no
    effect in this case.
    
    (cherry picked from commit fb5987fd571fca862c7230e15d7a5315db4dd9c9)

 app/paint/gimpsmudge.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/app/paint/gimpsmudge.c b/app/paint/gimpsmudge.c
index c991e03f24..2832000d4c 100644
--- a/app/paint/gimpsmudge.c
+++ b/app/paint/gimpsmudge.c
@@ -494,7 +494,7 @@ gimp_smudge_motion (GimpPaintCore    *paint_core,
        * gimp_gegl_smudge_with_paint() instead of calling
        * gegl_buffer_set_color() to reduce gegl's internal processing.
        */
-      if (! brush_color_ptr)
+      if (! brush_color_ptr && flow > 0.0)
         {
           gimp_brush_core_color_area_with_pixmap (brush_core, drawable,
                                                   coords, op,