[gimp] app: fix brush zoom verification in gimp_brush_core_pre_paint()

[N/A <ell src gnome org>]

commit 067277340d119cbf8fee88e93c83cfb7d920bef0
Author: Ell <ell_se yahoo com>
Date:   Fri Dec 22 10:04:12 2017 -0500

    app: fix brush zoom verification in gimp_brush_core_pre_paint()

 app/paint/gimpbrushcore.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/app/paint/gimpbrushcore.c b/app/paint/gimpbrushcore.c
index 5453766..8713707 100644
--- a/app/paint/gimpbrushcore.c
+++ b/app/paint/gimpbrushcore.c
@@ -326,12 +326,13 @@ gimp_brush_core_pre_paint (GimpPaintCore    *paint_core,
                                                       paint_options,
                                                       fade_point);
 
-              if (paint_options->brush_zoom)
+              if (paint_options->brush_zoom &&
+                  MAX (current_coords.xscale, current_coords.yscale) > 0)
                 {
-                  scale = scale / MAX (current_coords.xscale, current_coords.xscale);
+                  scale /= MAX (current_coords.xscale, current_coords.yscale);
 
-                  /*Cap transform result for brushes or OOM can occur*/
-                  if ((MAX (width, height)) > GIMP_BRUSH_MAX_SIZE)
+                  /* Cap transform result for brushes or OOM can occur */
+                  if ((scale * MAX (width, height)) > GIMP_BRUSH_MAX_SIZE)
                     {
                       scale = GIMP_BRUSH_MAX_SIZE / MAX (width, height);
                     }