On Mon, Nov 5, 2012 at 8:33 PM, Bruce <bruce@tomo.co.nz> wrote:
Martin, that may be the tip I have been looking for. I will experiment with this sometime. It also depends on how various pdf readers and printer drivers interpret the different approaches.
Besides Adobe Reader I get the best results using poppler-based viewers, like Evince (especially regarding the rendering of transparency groups).
I presume your recommendation applies to areas defined using drawing/clipping to the path, and not areas defined using patterns?
Exactly. The drawoptions were applied twice by MetaPost: * first time when drawing a symbol (e.g. block) to a temporary picture -- this time the "thclean qq" command overrides the default fill color (set by drawoptions) and fills the block area with a (transparent) color of scrap background * second time when this picture was (after clipping) added to other symbol drawings -- in this case MetaPost applies the default color to all lines (block border) and areas (interior of a block) drawn in the temporary picture.
And is it better to use drawoptions(); or thdrawoptions(); ?
They are used independently, but if you set the same option (like color) using both of them, drawoptions has a higher priority. Currently therion uses drawoptions to specify symbol colors and thdrawoptions are used in symbol definitions to specify dashed lines. Martin