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diff --git a/graphics/sketch/Doc/sketch/Bugs-and-anomalies.html b/graphics/sketch/Doc/sketch/Bugs-and-anomalies.html new file mode 100644 index 0000000000..422a1b525f --- /dev/null +++ b/graphics/sketch/Doc/sketch/Bugs-and-anomalies.html @@ -0,0 +1,95 @@ +<html lang="en"> +<head> +<title>Bugs and anomalies - Sketch</title> +<meta http-equiv="Content-Type" content="text/html"> +<meta name="description" content="Sketch"> +<meta name="generator" content="makeinfo 4.7"> +<link title="Top" rel="start" href="index.html#Top"> +<link rel="up" href="Hidden-surface-removal.html#Hidden-surface-removal" title="Hidden surface removal"> +<link rel="prev" href="Statistics.html#Statistics" title="Statistics"> +<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> +<!-- +Copyright (C) 2005, 2006, 2007, 2008 Eugene K. Ressler. + +This manual is for `sketch', version 0.2 (build 131), +Saturday, August 09, 2008, a program that converts descriptions of simple +three-dimensional scenes into static drawings. This version generates +`PSTricks' or `PGF/TikZ' code suitable for use with the +TeX document processing system. + +`Sketch' is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 3, or (at your option) +any later version. + +Sketch is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with `sketch'; see the file COPYING.txt. If not, see +http://www.gnu.org/copyleft.--> +<meta http-equiv="Content-Style-Type" content="text/css"> +<style type="text/css"><!-- + pre.display { font-family:inherit } + pre.format { font-family:inherit } + pre.smalldisplay { font-family:inherit; font-size:smaller } + pre.smallformat { font-family:inherit; font-size:smaller } + pre.smallexample { font-size:smaller } + pre.smalllisp { font-size:smaller } + span.sc { font-variant:small-caps } + span.roman { font-family: serif; font-weight: normal; } +--></style> +</head> +<body> +<div class="node"> +<p> +<a name="Bugs-and-anomalies"></a>Previous: <a rel="previous" accesskey="p" href="Statistics.html#Statistics">Statistics</a>, +Up: <a rel="up" accesskey="u" href="Hidden-surface-removal.html#Hidden-surface-removal">Hidden surface removal</a> +<hr><br> +</div> + +<!-- node-name, next, previous, up --> +<h5 class="subsubsection">4.4.3.2 Bugs and anomalies</h5> + +<p>Polygon and line splitting can both cause anomalies in the output. +<code>PSTricks</code> dash patterns, specified with <code>linestyle=dashed</code>, +<a name="index-linestyle-499"></a>can be disrupted by splitting. This occurs when the depth sort +<a name="index-depth-sort-500"></a>gives up too early and splits a line where it is not really +necessary. +A workaround is to use gray or finely dotted +lines instead. If your drawing is small, you can also edit the +<code>sketch</code> output by hand to merge the pieces of the offending +line. + + <p>Another anomaly is tiny (or in degenerate cases not-so-tiny) notches +in the lines that border split polygons. These derive from the way +each polygon is painted: first, all pixels within the boundary are +<dfn>filled</dfn> with color (perhaps white), then the same boundary is +<dfn>stroked</dfn> (a Postscript term) with a line. The result is that +half the line lies inside the boundary and half outside, while the +Painter's algorithm assumes the polygon lies entirely within its +boundary. The notches are due to one polygon fill operation +overwriting the already-drawn inside of the border of another +polygon.<a rel="footnote" href="#fn-1" name="fnd-1"><sup>1</sup></a> One workaround is to make +border lines very thin. In fact <code>linewidth=0pt</code> is guaranteed to +eliminate this problem, though this results in the thinnest line your +output device can draw, which is usually too thin. You might get +lucky by merely reordering things in the input file, which is likely +to move the splits to different places. The only sure-fire solution +is pretty terrible: custom fit <code>special</code> overlay lines (with +<code>\psline</code>) to cover the notches. + + <p>Polygon splitting also breaks <code>PSTricks</code> hatch patterns. The +only known workaround is to substitute a solid fill for the hatch. + + <div class="footnote"> +<hr> +<h4>Footnotes</h4><p class="footnote"><small>[<a name="fn-1" href="#fnd-1">1</a>]</small> I know how to fix this problem, but I don't like my +solution, and I'm interested in yours.</p> + + <p><hr></div> + + </body></html> + |