ikiwiki/doc/bugs/Problems_with_graphviz.pm_plug-in.mdwn

The graphviz.pm plug-in currently attempts to read PNG data in UTF-8 mode, which sometimes fail with a message similar to the following (depending on the input):

    utf8 "\x89" does not map to Unicode at /usr/local/lib/perl5/site_perl/5.8.8/IkiWiki/Plugin/graphviz.pm line 53, <IN> chunk 1.
    Wide character in subroutine entry at /usr/local/lib/perl5/site_perl/5.8.8/IkiWiki/Plugin/graphviz.pm line 68.

> Ok, will remove the binmode IN then. [[done]] --[[Joey]]

It also generates image URLs relative to the page being rendered, which means the URLs wont work when previewing a graph from the CGI script.

> You seem to be using an old version of ikiwiki, these preview isues have
> been fixed for some time, and the code doesn't look like what you patch
> in your second hunk. --[[Joey]]

The patch below fixes these two issues.

    --- graphviz.pm.orig	Thu Jun  7 15:45:16 2007
    +++ graphviz.pm	Fri Jun  8 12:03:38 2007
    @@ -41,7 +41,6 @@ sub render_graph (\%) { #{{{
     		$pid=open2(*IN, *OUT, "$params{prog} -Tpng");
     
     		# open2 doesn't respect "use open ':utf8'"
    -		binmode (IN, ':utf8');
     		binmode (OUT, ':utf8');
     
     		print OUT $src;
    @@ -70,7 +69,12 @@ sub render_graph (\%) { #{{{
     		}
     	}
     
    -	return "<img src=\"".urlto($dest, $params{page})."\" />\n";
    +	if ($params{preview}) {
    +		return "<img src=\"".urlto($dest, "")."\" />\n";
    +	}
    +	else {
    +		return "<img src=\"".urlto($dest, $params{page})."\" />\n";
    +	}
     } #}}}
     
     sub graph (@) { #{{{