create_bar_graph.in

#! /usr/bin/env perl
#
# Create a colour bar for a legend box.
#

use strict;
use warnings "all";
use Getopt::Tabular;
use File::Basename;
use File::Temp qw/ tempdir /;

my($Help, $Usage, $me);

my $min = 0;
my $max = 1.0;
my $colour_map = "spectral";
my $colour_map_file = undef;
my $bg = "black";
my $width = 50;
my $height = 6 * $width;

$me = &basename($0);

$Help = <<HELP;
| $me creates a colour bar for a legend box.
|
| Problems or comments should be sent to: claude\@bic.mni.mcgill.ca
HELP

$Usage = "Usage: $me [options] output.png\n".
         "       $me -help to list options\n\n";

my @opt_table = (
   ["-width", "float", 1, \$width, "width of bar image" ],
   ["-height", "float", 1, \$height, "height of bar image" ],
   ["-min", "float", 1, \$min, "minimum range (0-1)" ],
   ["-max", "float", 1, \$max, "maximum range (0-1)" ],
   ["-colour", "string", 1, \$colour_map,
      "colour map (choices are: gray, hot, hot_inv, cold_metal, cold_metal_inv," .
      "green_metal, green_metal_inv, lime_metal, lime_metal_inv," .
      "red_metal, red_metal_inv, purple_metal, purple_metal_inv," .
      "spectral, red, green, blue)" ],
   ["-usercc", "string", 1, \$colour_map_file,
      "user-defined colour map file" ],
   ["-bg", "string", 1, \$bg, "background colour" ]
   );

# Check arguments
&Getopt::Tabular::SetHelp($Help, $Usage);
&GetOptions (\@opt_table, \@ARGV) || exit 1;
die $Usage if(! ($#ARGV == 0));

my $outfile = shift(@ARGV);

# make tmpdir
my $tmpdir = &tempdir( "$me-XXXXXXXX", TMPDIR => 1, CLEANUP => 1 );

my $x_size = int $width + 0.5;    # round up
my $y_size = int $height + 0.5;

$min = $min * ( $y_size - 1 );
$max = $max * ( $y_size - 1 );

# first create the binary mnc file
my $i;
my @data = undef;
my $packstring = '';
for($i=0; $i<$y_size; $i++){
   $data[$i] = $i;
   $packstring .= 'f';
}
my $data = pack($packstring, @data);

open(FH, ">$tmpdir/tmp-float.raw");
for($i=0; $i<$x_size; $i++){
   syswrite(FH, $data);
}
close(FH);


# make minc file

&do_cmd( 'rawtominc', '-clobber', '-float',
         '-input', "$tmpdir/tmp-float.raw",
	 '-xstep', 1, '-ystep', 1, '-zstep', 1,
         '-xstart', 0, '-ystart', 0, '-zstart', 0,
         '-dimorder', 'xspace,yspace,zspace',
         "$tmpdir/bar.mnc", $x_size, $y_size, 1 );

# make .rgb bar image using ray_trace

my @colour_args = ();
if( defined $colour_map_file ) {
  push @colour_args, "-usercc";
  push @colour_args, $colour_map_file;
} else {
  push @colour_args, "-${colour_map}";
}

&do_cmd( 'make_slice', "$tmpdir/bar.mnc", "$tmpdir/slice.obj", 0, 0, 0, 0, 0, 1 );
&do_cmd( 'ray_trace', '-output', "$tmpdir/bar.rgb", '-light', '-bg', $bg,
         '-ortho', '-top', '-size', $x_size, $y_size, '-window_width', $x_size,
         @colour_args, $min, $max, "$tmpdir/bar.mnc", 0, 1,
         "$tmpdir/slice.obj" );

# convert from .rgb to .png

&do_cmd('convert', "$tmpdir/bar.rgb", $outfile );

sub do_cmd {
   system(@_) == 0 or die "Failed: @_\n";
}