From 5b6a4d794ff795f99856cd0fde775dc6f77aa4d2 Mon Sep 17 00:00:00 2001
From: Seth Hillbrand <seth@kipro-pcb.com>
Date: Tue, 25 Feb 2020 07:36:41 -0800
Subject: [PATCH] pcbnew: Avoid wx scaling error

When drawing to a scaled DC, the window doesn't reflect the expected
size if scaled after.  This causes elements drawn on the edge to reflect
back into the drawing area instead of being cut off.

We can simply scale our own values to avoid this issue.

Fixes #3849 | https://gitlab.com/kicad/code/kicad/issues/3849
---
 .../dialog_pad_basicshapes_properties.cpp     | 38 ++++++-------------
 1 file changed, 12 insertions(+), 26 deletions(-)

diff --git a/pcbnew/dialogs/dialog_pad_basicshapes_properties.cpp b/pcbnew/dialogs/dialog_pad_basicshapes_properties.cpp
index 3f3b9bec2c..963a243ff4 100644
--- a/pcbnew/dialogs/dialog_pad_basicshapes_properties.cpp
+++ b/pcbnew/dialogs/dialog_pad_basicshapes_properties.cpp
@@ -348,13 +348,13 @@ bool DIALOG_PAD_PRIMITIVE_POLY_PROPS::doValidate( bool aRemoveRedundantCorners )
 
     if(  polyline.PointCount() < 3 )
     {
-        m_warningText->SetLabel( _("Polygon must have at least 3 corners after simplification" ) );
+        m_warningText->SetLabel( _( "Polygon must have at least 3 corners after simplification" ) );
         valid = false;
     }
 
     if( valid && polyline.SelfIntersecting() )
     {
-        m_warningText->SetLabel( _("Polygon may not be self-intersecting" ) );
+        m_warningText->SetLabel( _( "Polygon can not be self-intersecting" ) );
         valid = false;
     }
 
@@ -372,7 +372,7 @@ bool DIALOG_PAD_PRIMITIVE_POLY_PROPS::doValidate( bool aRemoveRedundantCorners )
 
             m_warningIcon->Show( true );
             m_warningText->Show( true );
-            m_warningText->SetLabel( _("Note: redundant corners removed" ) );
+            m_warningText->SetLabel( _( "Note: redundant corners removed" ) );
         }
     }
 
@@ -459,43 +459,29 @@ void DIALOG_PAD_PRIMITIVE_POLY_PROPS::onPaintPolyPanel( wxPaintEvent& event )
     dc.SetDeviceOrigin( dc_size.x / 2, dc_size.y / 2 );
 
     // Calculate a suitable scale to fit the available draw area
-    wxSize minsize;
+    int minsize( Millimeter2iu( 0.5 ) );
 
     for( unsigned ii = 0; ii < m_currshape.m_Poly.size(); ++ii )
     {
-        minsize.x = std::max( minsize.x, std::abs( m_currshape.m_Poly[ii].x ) );
-        minsize.y = std::max( minsize.y, std::abs( m_currshape.m_Poly[ii].y ) );
+        minsize = std::max( minsize, std::abs( m_currshape.m_Poly[ii].x ) );
+        minsize = std::max( minsize, std::abs( m_currshape.m_Poly[ii].y ) );
     }
 
     // The draw origin is the center of the window.
     // Therefore the window size is twice the minsize just calculated
-    minsize.x *= 2;
-    minsize.y *= 2;
-    minsize.x += m_currshape.m_Thickness;
-    minsize.y += m_currshape.m_Thickness;
-
-    // Avoid null or too small size:
-    int mindim = Millimeter2iu( 0.5 );
-
-    if( minsize.x < mindim )
-        minsize.x = mindim;
-
-    if( minsize.y < mindim )
-        minsize.y = mindim;
-
-    double scale = std::min( (double) dc_size.x / minsize.x, (double) dc_size.y / minsize.y );
+    minsize *= 2;
+    minsize += m_currshape.m_Thickness;
 
     // Give a margin
-    scale *= 0.9;
-    dc.SetUserScale( scale, scale );
+    double scale = std::min( double( dc_size.x ) / minsize, double( dc_size.y ) / minsize ) * 0.9;
 
     GRResetPenAndBrush( &dc );
 
     // Draw X and Y axis. This is particularly useful to show the
     // reference position of basic shape
     // Axis are drawn before the polygon to avoid masking segments on axis
-    GRLine( NULL, &dc, -int( dc_size.x/scale ), 0, int( dc_size.x/scale ), 0, 0, LIGHTBLUE );   // X axis
-    GRLine( NULL, &dc, 0, -int( dc_size.y/scale ), 0, int( dc_size.y/scale ), 0, LIGHTBLUE );   // Y axis
+    GRLine( NULL, &dc, -dc_size.x, 0, dc_size.x, 0, 0, LIGHTBLUE );   // X axis
+    GRLine( NULL, &dc, 0, -dc_size.y, 0, dc_size.y, 0, LIGHTBLUE );   // Y axis
 
     // Draw polygon.
     // The selected edge(s) are shown in selectcolor, the others in normalcolor.
@@ -516,7 +502,7 @@ void DIALOG_PAD_PRIMITIVE_POLY_PROPS::onPaintPolyPanel( wxPaintEvent& event )
         if( jj >= m_currshape.m_Poly.size() )
             jj = 0;
 
-        GRLine( NULL, &dc, m_currshape.m_Poly[ii], m_currshape.m_Poly[jj], m_currshape.m_Thickness, color );
+        GRLine( NULL, &dc, m_currshape.m_Poly[ii] * scale, m_currshape.m_Poly[jj] * scale, m_currshape.m_Thickness * scale, color );
     }
 
     event.Skip();