# NAME

Math::Spiral - Perl extension to return an endless stream of X, Y offset coordinates which represent a spiral shape

# SYNOPSIS

``````    #!/usr/bin/perl -w

use Math::Spiral;

my \$s = new Math::Spiral();
my(\$xo,\$yo)=\$s->Next();

# perl -MMath::Spiral -e '\$s=new Math::Spiral(); foreach(0..9) { (\$xo,\$yo)=\$s->Next(); \$chart[2+\$xo][2+\$yo]=\$_; } foreach \$y (0..4){foreach \$x(0..4){if(defined(\$chart[\$x][\$y])){print \$chart[\$x][\$y]} else {print " ";} } print "\n"}'``````

# DESCRIPTION

This module outputs an infinte sequence of coordinate offsets, which you can use to plot things in a spiral shape. The numbers return "clockwise"; negate one if you want to go anti-clockwise instead.

It is useful for charting things where you need to concentrate something around the center of the chart.

## EXAMPLE

``````    #!/usr/bin/perl -w

use Math::Spiral;

my \$s = new Math::Spiral();

foreach(0..9) {
(\$xo,\$yo)=\$s->Next();     # Returns a sequnce like (0,0) (1,0) (1,1) (0,1) (-1,1) (-1,0) (-1,-1) (0,-1) (1,-1) (2,-1) ... etc
\$chart[2+\$xo][2+\$yo]=\$_;
}

foreach \$y (0..4) {
foreach \$x(0..4) {
if(defined(\$chart[\$x][\$y])) {
print \$chart[\$x][\$y]
} else {
print " ";
}
}
print "\n"
}``````

### Prints

`````` 6789
501
432 ``````

None by default.

## new

Usage is

``    my \$s = new Math::Spiral();``

## Next

Returns the next x and y offsets (note that these start at 0,0 and will go negative to circle around this origin)

Usage is

``````    my(\$xo,\$yo)=\$s->Next();
# Returns a sequnce like (0,0) (1,0) (1,1) (0,1) (-1,1) (-1,0) (-1,-1) (0,-1) (1,-1) (2,-1) ... etc (i.e. the x,y coordinates for a spiral)``````

# AUTHOR

This module was written by Chris Drake cdrake@cpan.org