From ebd183d58e2e8914c79e0bf304ba3bbfdb433cdc Mon Sep 17 00:00:00 2001
From: artemp <artem@mapnik.org>
Date: Tue, 5 Aug 2014 11:57:57 +0100
Subject: [PATCH] avoid overflowing

---
 src/agg/process_polygon_pattern_symbolizer.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/agg/process_polygon_pattern_symbolizer.cpp b/src/agg/process_polygon_pattern_symbolizer.cpp
index bc0ceb89c..c35665535 100644
--- a/src/agg/process_polygon_pattern_symbolizer.cpp
+++ b/src/agg/process_polygon_pattern_symbolizer.cpp
@@ -143,8 +143,8 @@ void agg_renderer<T0,T1>::process(polygon_pattern_symbolizer const& sym,
             path_type path(common_.t_,clipped,prj_trans);
             path.vertex(&x0,&y0);
         }
-        offset_x = unsigned(current_buffer_->width() - x0);
-        offset_y = unsigned(current_buffer_->height() - y0);
+        offset_x = std::abs(current_buffer_->width() - x0);
+        offset_y = std::abs(current_buffer_->height() - y0);
     }
 
     span_gen_type sg(img_src, offset_x, offset_y);