Symbol line direction in curved polygon

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    • #2599
      Barry Kelly
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      I am modifying a GS hedge object to make it a little more useful for myself.
      I want to add a ‘grass’ symbol line type to the perimeter in plan to make it look a little more hedgy.
      This works fine when the perimeter is closed on a curved hedge.
      But as soon as I use the masking code to turn off the line for one edge the line on the inside curve inverts for some reason.
      There is no problem at all for a straight hedge – only when the polygon has a curve it seems.

      Here is the code used for the polygon.

      rad = 1.000
      breit = 0.500
      wink = 90
      
      end_1_swch = 1
      end_2_swch = 0	 !!change to 1 to close polygon
      
      poly2_b 7,1+2+4,gs_fill_pen,gs_back_pen,
      	rad,0,end_1_swch,
      	rad+breit,0,1,
      	0,0,900,
      	(rad+breit)*cos(wink),(rad+breit)*sin(wink),3000+end_2_swch,
      	rad*cos(wink),rad*sin(wink),1,
      	0,0,900,
      	rad, 0,3001
      

      Reversing the polygon doesn’t help either.

      add2 1.5, 0
      poly2_b 7,1+2+4,gs_fill_pen,gs_back_pen,
      	rad,0,1,
      	0,0,900,
      	rad*cos(wink),rad*sin(wink),3000+end_2_swch,
      	(rad+breit)*cos(wink),(rad+breit)*sin(wink),1,
      	0,0,900,
      	rad+breit,0,3000+end_1_swch,
      	rad, 0,1
      del 1
      
      

      Even using ARC2 won’t help as you can’t reverse the direction of the line and can’t use a negative radius.

      Is this a bug (and if so can it be fixed)?
      Any ideas for a solution that doesn’t involve creating a new symbol line type that is reversed in the y direction and then using two polygons with various edges hidden or not?

      I am guessing that the positive y portion of a symbol line will always project towards the centre of an arc unless in a closed polygon with visible edges in which the direction can be reversed depending on the order of node scripting.

      Barry.

      Attachments:

      Versions 6.5 to 22
      Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
      Dell Precision M6800 - i7 4700MQ @ 2.40GHz, 16GB RAM, AMD FirePro M6100 (2GB), Windows 7 64bit

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