kicad-developers team mailing list archive

[Cirilo Bernardo <cirilo_bernardo@xxxxxxxxx>]

Hi folks,

 There is a bug in DXF plot which changes the included angle of arcs. To demonstrate the bug:

1. in the edge cutout layer, create a rectangle with rounded corners and plot the layer to DXF. Since KiCad will write a PCB file with all angles = +90, everything is OK.

2. Delete the cutout layer and import the DXF. At this point everything should look OK.

3. Plot the dxf again; this time things go bad because the DXF importer marked some angles as -90 in Step 2.

4. Import the bad DXF (or view it with MCAD software).

I have only fixed the bug in BRDITEMS_PLOTTER::PlotDrawSegment and only for DXF plotting. I did not create tests to check if the problem exists with other types of plotting routines (it is possible others are affected, but not necessarily so) and I did not investigate problems with exporting an Arc in BRDITEMS_PLOTTER::Plot_1_EdgeModule.

Cheers,
Cirilo

=== modified file 'pcbnew/plot_brditems_plotter.cpp'
--- pcbnew/plot_brditems_plotter.cpp	2013-12-05 12:24:27 +0000
+++ pcbnew/plot_brditems_plotter.cpp	2013-12-17 09:49:54 +0000
@@ -401,7 +401,7 @@
         double startAngle  = ArcTangente( end.y - pos.y, end.x - pos.x );
 
         double endAngle = startAngle + aEdge->GetAngle();
-
+                
         if ( ( GetFormat() == PLOT_FORMAT_DXF ) &&
              ( m_layerMask & ( SILKSCREEN_LAYER_BACK | DRAW_LAYER | COMMENT_LAYER ) ) )
             m_plotter->ThickArc( pos, -startAngle, -endAngle, radius, thickness, GetMode() );
@@ -615,6 +615,23 @@
         radius = KiROUND( GetLineLength( end, start ) );
         StAngle  = ArcTangente( end.y - start.y, end.x - start.x );
         EndAngle = StAngle + aSeg->GetAngle();
+
+        if ( GetFormat() == PLOT_FORMAT_DXF )
+        {
+            if( aSeg->GetAngle() >= -1800 && aSeg->GetAngle() <= 1800 )
+            {
+                // ensure that normally startAngle < endAngle
+                if( StAngle > EndAngle )
+                    std::swap( StAngle, EndAngle );
+            }
+            else
+            {
+                // ensure that normally startAngle > endAngle
+                if( StAngle < EndAngle )
+                    std::swap( StAngle, EndAngle );
+            }
+        }
+
         m_plotter->ThickArc( start, -EndAngle, -StAngle, radius, thickness, GetMode() );
         break;