| Summary: | lines in antialiased tesselated polygon rendering | ||
|---|---|---|---|
| Product: | Ghostscript | Reporter: | Adolf Mathias <dolfi> |
| Component: | Graphics Library | Assignee: | Jack Moffitt <jack> |
| Status: | RESOLVED DUPLICATE | ||
| Severity: | normal | ||
| Priority: | P2 | ||
| Version: | 8.14 | ||
| Hardware: | All | ||
| OS: | All | ||
| Customer: | Word Size: | --- | |
It looks to me that you are dividing everything into adjoining triangles. If you do this, you are going to see the white lines you are talking about due to antialiasing (it's probably there with varying degree depending on resolution). This is just a standard antialiasing artifact, not a bug in Ghostscript. |
When rendering tesselated polygons using -dGraphicsAlphaBits, I get thin white lines along the tesselation lines. Using coordinates generated e.g. by arc, they're not there. (Tested with 8.14 under both Linux and Windows, using the X11 display driver and several 24 bit bitmap drivers) %!/PS-Adobe-2.0 % gs -dTextAlphaBits=4 -dGraphicsAlphaBits=4 -r72 -g600x600 /buf 64 string def /tri % x0 y0 x1 y1 x2 y2 tri x0 y0 x2 y2 draws a triangle { 4 2 roll moveto 2 copy lineto % print device coords of x2 y2 2 copy transform exch (x:) print buf cvs print (\ty:) print buf cvs print (\n) print 3 index 3 index lineto fill } def % A circle flattened down to an octagon, tesselated /test1 { 100 setflat 300 300 200 -90 270 arc flattenpath { 2 copy } { tri } { 6 -2 roll tri 4 -2 roll tri tri } { 3 index 3 index tri pop pop pop pop } pathforall } def /test2 { gsave 300 300 translate 200 200 scale 0 setlinewidth -90 dup cos 1 index sin 2 copy 5 -1 roll 45 exch 1 index add exch 270 { dup cos exch sin tri } for pop pop pop pop grestore } def test1 showpage test2 showpage