#!/bin/rc
# wshot: take a screenshot of a rio window
rfork e

fn usage{
	echo usage: wshot labelpattern out.png >[1=2]
	exit usage
}
fn error{
	echo $* >[1=2]
	exit $"*
}

if(! ~ $#* 2) usage

pat=$1
out=$2

if(test -e $out)
	error $out already exists

label=`{grep -l $pat /dev/wsys/*/label}

switch($#label){
case 0
	error no matches
case 1
	wdir=`{basename -d $label}
case *
	error multiple matches
}

topng $wdir/window >$out