#!/usr/bin/perl
#Converts a text file into postcript file describing a kite-diagram
#Usage: kitediagram.pl <input-file-name>
#The input file format is CSV. The first line is a list of labels for the x-axis
#Subsequent lines consist of a label for that kite, and a list of measurements

use POSIX qw(ceil floor);

#Get the name of the input file, and open it
$file=$ARGV[0];
if(!$file){$file="data.txt"};
open(INPUT, "<$file") or die "Could not open $file for reading";

#Form the name of the output file, and open it
($outputName, $trash)=split('\.', $file);
$outputName .= ".ps";
open(MYOUTPUTFILE, ">$outputName") or die "Could not open $outputName for writing";


#Read the input file, splitting out the x-axis labels, and putting the others straight into an array
$rowNumber=-1;
while(<INPUT>)
{
	$rowNumber++;
	$line=$_;
	
	if ($rowNumber==0){
		@xAxisLabels = split(',', $line);
	}else{
		push(@lines, $line);
	}

}

#Work out the scale factor, before we start decremating $rowNumber
$vSpaceNeeded= 130 + 120*($rowNumber-1);
$vScaleFactor= 792 /$vSpaceNeeded;


#form the postscript needed to graph each line
while($rowNumber > 0){
	
	($label, @data)=split(',', $lines[$rowNumber-1]);
	$spaceLeft = 20;
	$width = floor( (612-$spaceLeft) / (scalar @data) ); #horizonatal space between data-points

	$rightCoord 	= $width * (scalar @data - 1) + $spaceLeft;
	$centerHeight 	= 60 + 120*($rowNumber-1);
	#$centerHeight	= 792 - $centerHeight;
	#$centerHeight 	= 742 - 120*($rowNumber-1);
	
	$topHeight 		= $centerHeight+50;
	$bottomHeight	= $centerHeight-50;
	$tickLeft = $spaceLeft - 4; #4 is the length of the tick

	$labelTop=$topHeight-4;
	$labelMiddle=$centerHeight-4;
	$labelBottom=$bottomHeight-4;

	$output .= topCurve();
	$output .= bottomCurve();
	$output .= xAxis();
	$output .= yAxis();
	$output .= xAxisLabels(@xAxisLabels);
	$output .= title();
	
	$rowNumber -= 1;
}

#output the postscript and close the file
print MYOUTPUTFILE "1 $vScaleFactor scale\n";
print MYOUTPUTFILE $output; 
close MYOUTPUTFILE;



sub xAxis {
#The axis:
$xAxis .= <<AXES;

%x-axis 
0 setgray
0 setlinewidth
newpath
$spaceLeft $centerHeight moveto 
$rightCoord $centerHeight lineto
stroke

%x-labels
/Times-Roman findfont
10 scalefont
setfont
newpath
0 $labelTop moveto
(100) show
0 $labelMiddle moveto
(0) show
0 $labelBottom moveto
(100) show

AXES

#and its ticks 
$xAxis .= "%x-ticks\n";
$xAxis .= "newpath\n";
#$xAxis .= "1 0 0 setrgbcolor\n";
$xAxis .= "0 setgray\n";

for($count=0; $count<scalar @data; $count++){
	$xAxis .= join " ", ($count*$width + $spaceLeft), $centerHeight, " moveto \n";
	$xAxis .= join " ", ($count*$width + $spaceLeft), ($centerHeight-3), " lineto \n";
}
$xAxis .= "stroke \n";
$xAxis .= "0 setgray\n";


return $xAxis;
}

sub yAxis{
	
#The line:
$yAxis = <<AXES;
0 setgray
%y-axis
0.1 setlinewidth
newpath 
$spaceLeft $centerHeight moveto 
$spaceLeft $topHeight lineto 
$spaceLeft $bottomHeight lineto 
stroke
	
AXES

#The 20 ticks:
$yAxis .= "%y-ticks \n newpath \n";
for ($count=-10; $count <= 10; $count=$count+1){
$yAxis .= "$spaceLeft " . ($centerHeight + $count*5) . " moveto \n"; 
$yAxis .= "$tickLeft " . ($centerHeight + $count*5) . " lineto \n"; 
}
$yAxis .= "stroke \n\n";


return $yAxis;	
}

sub topCurve{
$topCurve .= <<DATA;

%Top curve
newpath
.5 setgray
$spaceLeft $centerHeight moveto 
DATA

	$topCurve .= "$spaceLeft " . ($data[0]/2+$centerHeight) . " lineto \n";
	for($count=1; $count<scalar @data; $count++){
		$topCurve .= join " ",, ($spaceLeft + ($width * $count)), ($data[$count]/2 + $centerHeight), " lineto \n";

	}
	$topCurve .= join " ", $rightCoord, $centerHeight, " lineto\n";
	$topCurve .= "$spaceLeft $centerHeight moveto\n";
	$topCurve .= "fill\n";
	
return $topCurve;	
}

sub bottomCurve{
$bottomCurve .= <<DATA;


%Bottom curve
newpath
$spaceLeft $centerHeight moveto 
DATA

	$bottomCurve .=  "$spaceLeft " . (- $data[0]/2 + $centerHeight) . " lineto \n";
	for($count=1; $count<scalar @data; $count++){
		$bottomCurve .=  join " ",, ($spaceLeft + ($width * $count)), ( - $data[$count]/2 + $centerHeight), " lineto \n";

	}
	$bottomCurve .= join " ", $rightCoord, $centerHeight, " lineto\n";
	$bottomCurve .= "$spaceLeft $centerHeight moveto\n";
	$bottomCurve .=  "fill\n";
	
return $bottomCurve;	
}

sub xAxisLabels{
	#accepts an array as argument; but we see it as a list of scalars in @_
	$xAxisLabels .= "%y-Axis Labels\n";
	$xAxisLabels .= "newpath\n";
	#$xAxisLabels .= "1 0 0 setrgbcolor\n";
	$xAxisLabels .= "0 setgray\n";
	
	$y= $centerHeight - 12;
	
	for($count=0; $count<scalar @_; $count++){
		
		$x= ($count*$width + $spaceLeft) - 6;
		
$xAxisLabels .= <<DATA
/Times-Roman findfont
10 scalefont
setfont
$x $y moveto
($_[$count]) show
DATA
	}
$xAxisLabels .= "0 setgray\n";
	
return $xAxisLabels;

}

sub title{
$titleHeight=$topHeight + 4;
	$title .= "newpath\n";
$title .= <<DATA
/Times-Roman findfont
10 scalefont
setfont
2 $titleHeight moveto
($label) show
DATA
}