From b877098bac8d7bcdd98a9634dce02c603475f05f Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Mon, 2 Nov 2009 16:22:10 +0000
Subject: [PATCH] fix draw-arc to skip drawing instead of setting the scale to
 0

svn: r16502
---
 src/wxxt/src/DeviceContexts/WindowDC.cc | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/wxxt/src/DeviceContexts/WindowDC.cc b/src/wxxt/src/DeviceContexts/WindowDC.cc
index 362577fd97..ee8203fdf1 100644
--- a/src/wxxt/src/DeviceContexts/WindowDC.cc
+++ b/src/wxxt/src/DeviceContexts/WindowDC.cc
@@ -1217,16 +1217,20 @@ void wxWindowDC::DrawArc(double x, double y, double w, double h, double start, d
       yy = SmoothingXFormY(y);
       ww = SmoothingXFormWL(w, x);
       hh = SmoothingXFormHL(h, y);
-      
-      cairo_set_matrix_create(m);
-      cairo_current_matrix (CAIRO_DEV, m);
-      cairo_translate(CAIRO_DEV, xx, yy);
-      cairo_scale(CAIRO_DEV, ww, hh);
-      cairo_new_path(CAIRO_DEV);
-      cairo_arc_negative(CAIRO_DEV, 0.5, 0.5, 0.5, start, end);
-      cairo__set_matrix(CAIRO_DEV, m);
-      cairo_stroke(CAIRO_DEV);
-      cairo_matrix_destroy(m);
+
+      if ((ww > 0.0) && (hh > 0.0)) {
+        cairo_save(CAIRO_DEV);
+        cairo_set_matrix_create(m);
+        cairo_current_matrix (CAIRO_DEV, m);
+        cairo_translate(CAIRO_DEV, xx, yy);
+        cairo_scale(CAIRO_DEV, ww, hh);
+        cairo_new_path(CAIRO_DEV);
+        cairo_arc_negative(CAIRO_DEV, 0.5, 0.5, 0.5, start, end);
+        cairo__set_matrix(CAIRO_DEV, m);
+        cairo_stroke(CAIRO_DEV);
+        cairo_restore(CAIRO_DEV);
+        cairo_matrix_destroy(m);
+      }
     }
 
     return;