From bf71a4e012cc10b6430e77ee5fcf7044f450d018 Mon Sep 17 00:00:00 2001
From: jean-pierre charras <jp.charras@wanadoo.fr>
Date: Tue, 18 Aug 2020 10:26:10 +0200
Subject: [PATCH] Gerbview: fix draw issue when drawing a line using a
 rectangular aperture. Lines using a rectangular aperture are not common, but
 this is legal in Gerber files.

Fixes #5205
https://gitlab.com/kicad/code/kicad/issues/5205
---
 gerbview/gerber_draw_item.cpp | 7 ++++---
 gerbview/gerbview_painter.cpp | 7 ++++++-
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/gerbview/gerber_draw_item.cpp b/gerbview/gerber_draw_item.cpp
index fe61ac33c0..7a6c4a9463 100644
--- a/gerbview/gerber_draw_item.cpp
+++ b/gerbview/gerber_draw_item.cpp
@@ -666,17 +666,18 @@ void GERBER_DRAW_ITEM::DrawGbrPoly( EDA_RECT*      aClipBox,
                                     const wxPoint& aOffset,
                                     bool           aFilledShape )
 {
-    std::vector<wxPoint> points;
     SHAPE_LINE_CHAIN& poly = m_Polygon.Outline( 0 );
     int pointCount = poly.PointCount() - 1;
 
+    std::vector<wxPoint> points;
     points.reserve( pointCount );
 
     for( int ii = 0; ii < pointCount; ii++ )
     {
         wxPoint p( poly.Point( ii ).x, poly.Point( ii ).y );
-        points[ii] = p + aOffset;
-        points[ii] = GetABPosition( points[ii] );
+        p = p + aOffset;
+        p = GetABPosition( p );
+        points.push_back( p );
     }
 
     GRClosedPoly( aClipBox, aDC, pointCount, &points[0], aFilledShape, aColor, aColor );
diff --git a/gerbview/gerbview_painter.cpp b/gerbview/gerbview_painter.cpp
index 7920d30b25..6f87b74f4e 100644
--- a/gerbview/gerbview_painter.cpp
+++ b/gerbview/gerbview_painter.cpp
@@ -360,11 +360,16 @@ void GERBVIEW_PAINTER::draw( /*const*/ GERBER_DRAW_ITEM* aItem, int aLayer )
 
         // TODO(JE) Refactor this to allow const aItem
         D_CODE* code = aItem->GetDcodeDescr();
+
         if( code && code->m_Shape == APT_RECT )
         {
             if( aItem->m_Polygon.OutlineCount() == 0 )
                 aItem->ConvertSegmentToPolygon();
-            drawPolygon( aItem, aItem->m_Polygon, isFilled );
+
+            // Warning: drawPolygon modify the polygon to draw, so use a copy
+            // of aItem->m_Polygon
+            SHAPE_POLY_SET poly = aItem->m_Polygon;
+            drawPolygon( aItem, poly, isFilled );
         }
         else
         {