[gimp/gtk3-port: 336/336] app: avoid scaling GimpCanvasArc to zero, it causes a non-invertable matrix

[Michael Natterer <mitch src gnome org>]

commit 7efc74b438aa76b15df6e1b593b8bfa8f5626e0f
Author: Michael Natterer <mitch gimp org>
Date:   Fri May 4 11:45:14 2018 +0200

    app: avoid scaling GimpCanvasArc to zero, it causes a non-invertable matrix

 app/display/gimpcanvasarc.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/app/display/gimpcanvasarc.c b/app/display/gimpcanvasarc.c
index 9c82971..6104095 100644
--- a/app/display/gimpcanvasarc.c
+++ b/app/display/gimpcanvasarc.c
@@ -256,6 +256,10 @@ gimp_canvas_arc_transform (GimpCanvasItem *item,
       *radius_x = MAX (*radius_x - 0.5, 0.0);
       *radius_y = MAX (*radius_y - 0.5, 0.0);
     }
+
+  /* avoid cairo_scale (cr, 0.0, 0.0) */
+  if (*radius_x == 0.0) *radius_x = 0.000001;
+  if (*radius_y == 0.0) *radius_y = 0.000001;
 }
 
 static void