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Message #11908
Re: patch to fix bug in DXF plot
----- Original Message -----
> From: Wayne Stambaugh <stambaughw@xxxxxxxxxxx>
> To: kicad-developers@xxxxxxxxxxxxxxxxxxx
> Cc:
> Sent: Thursday, December 19, 2013 8:52 AM
> Subject: Re: [Kicad-developers] patch to fix bug in DXF plot
>
> On 12/17/2013 5:03 AM, Cirilo Bernardo wrote:
>
>> 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
>
> Your patch does not work for the attached board edge cuts layer so I am
> reluctant to commit it. It may work for your case but it may have
> broken another corner case. Don't feel bad, the current DXF plot does
> not plot this board correctly either. I've known about this problem for
> a while but have been too lazy to fix it. There is some oddness in the
> way the DXF defines arcs that I am not completely familiar with. If you
> can get the attached board to plot correctly without breaking all of the
> other DXF arc plotting, you'll get a hardy pat on back and your patch
> committed. :) Also, your editor is leaving trailing white space which
> is a violation of the coding policy.
>
> What I really would like to see is converting our DXF plotting over to
> use the dxflib that JP recently added to the project. It seems like a
> much more complete solution which could give us better results in terms
> of layer and color support. Arcs with width would be nice too. Maybe
> you could become the guru of DXF plotting.
>
> Thanks,
>
> Wayne
>
>
After more experimentation with DXF, I'm confident I've got it right this time. I also patched the rendering of module outlines. The previous suggested patch was indeed incorrect and some items would render fine while others were wrong.
- 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 2013-12-19 07:38:11 +0000
@@ -402,6 +402,15 @@
double endAngle = startAngle + aEdge->GetAngle();
+ if ( GetFormat() == PLOT_FORMAT_DXF )
+ {
+ if( aEdge->GetAngle() < 0 )
+ std::swap( startAngle, endAngle );
+
+ if( m_layerMask & ( SILKSCREEN_LAYER_BACK | DRAW_LAYER | COMMENT_LAYER ) )
+ std::swap( startAngle, endAngle );
+ }
+
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 +624,13 @@
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() < 0 )
+ std::swap( StAngle, EndAngle );
+ }
+
m_plotter->ThickArc( start, -EndAngle, -StAngle, radius, thickness, GetMode() );
break;
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