SYNOPSIS
use Math::PlanePath::Columns;
my $path = Math::PlanePath::Columns>new;
my ($x, $y) = $path>n_to_xy (123);
DESCRIPTION
This path is columns of a given fixed height. For example height 5 would be
 4  5 10 15 20 < height==5 3  4 9 14 19 2  3 8 13 18 1  2 7 12 17 ... Y=0  1 6 11 16 21  X=0 1 2 3 4 ...
N Start
The default is to number points starting N=1 as shown above. An optional "n_start" can give a different start, with the same shape. For example to start at 0,
n_start => 0, height => 5 4  4 9 14 19 3  3 8 13 18 2  2 7 12 17 1  1 6 11 16 ... Y=0  0 5 10 15 20  X=0 1 2 3 4 ...
The only effect is to push the N values around by a constant amount. It might help match coordinates with something else zerobased.
FUNCTIONS
See ``FUNCTIONS'' in Math::PlanePath for behaviour common to all path classes. "$path = Math::PlanePath::Columns>new (height => $h)"
 "$path = Math::PlanePath::Columns>new (height => $h, n_start => $n)"
 Create and return a new path object. A "height" parameter must be supplied.
 "($x,$y) = $path>n_to_xy ($n)"
 Return the X,Y coordinates of point number $n in the path.
 "$n = $path>xy_to_n ($x,$y)"

Return the point number for coordinates "$x,$y".
$x and $y are rounded to the nearest integers, which has the effect of treating each point in the path as a square of side 1, so a rectangle $x >= 0.5 and 0.5 <= y < height+0.5 is covered.
 "($n_lo, $n_hi) = $path>rect_to_n_range ($x1,$y1, $x2,$y2)"
 The returned range is exact, meaning $n_lo and $n_hi are the smallest and biggest in the rectangle.
LICENSE
Copyright 2010, 2011, 2012, 2013, 2014, 2015, 2016 Kevin RydeThis file is part of MathPlanePath.
MathPlanePath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.
MathPlanePath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with MathPlanePath. If not, see <http://www.gnu.org/licenses/>.