#!/usr/bin/perl -wp -00

use Getopt::Std;
use strict;
use vars qw(%opts);

BEGIN {
    %opts = (
	y => 6,
    );
    getopts('y:', \%opts);
}

my ($g_id, $p_opts, $t_opts, $t_str) =
    m#<g id="(\w+)" class="edge">.*<path (.*?)/>.*<text (.*?)>(.*?)</text>#s;
next unless $t_str;
s#<path #<path id="${g_id}_p" #;
$t_opts = " $t_opts";
$t_opts =~ s# x=".*?"##;
$t_opts =~ s# y=".*?"##;
my (@lines) = m#<text .*?>(.*?)</text>#g;
if ($#lines > 0) {
    foreach (@lines) {
	$_ = qq(<tspan x="0" dy="$opts{y}">$_</tspan>);
    }
    my ($y0) = - int($#lines/2)*$opts{y};
    $lines[0] =~ s/dy="\d+"/dy="$y0"/;
    s|(<text .*?>.*?</text>\s*)+|$1|s;
    $t_str = join("\n", @lines);
    # http://stackoverflow.com/questions/5185699/multiple-lines-of-curved-text-in-svg
}
s|<text .*?>.*?</text>|<text $t_opts><textPath
    xlink:href="#${g_id}_p" startOffset="50%">$t_str</textPath></text>|;