 Math::PlanePath::Rows(3) points in fixed-width rows

## SYNOPSIS

use Math::PlanePath::Rows;
my \$path = Math::PlanePath::Rows->new (width => 20);
my (\$x, \$y) = \$path->n_to_xy (123);

## DESCRIPTION

This path is rows of a given fixed width. For example width=7 is

```    width => 7
3  |  22  23  24 ...
2  |  15  16  17  18  19  20  21
1  |   8   9  10  11  12  13  14
Y=0  |   1   2   3   4   5   6   7
-------------------------------
X=0   1   2   3   4   5   6
```

## 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, width => 7
3  |  21  22  23  24 ...
2  |  14  15  16  17  18  19  20
1  |   7   8   9  10  11  12  13
Y=0  |   0   1   2   3   4   5   6
-------------------------------
X=0   1   2   3   4   5   6
```

The only effect is to push the N values around by a constant amount. It might help match coordinates with something else zero-based.

## FUNCTIONS

See ``FUNCTIONS'' in Math::PlanePath for behaviour common to all path classes.
"\$path = Math::PlanePath::Rows->new (width => \$w)"
"\$path = Math::PlanePath::Rows->new (width => \$w, n_start => \$n)"
Create and return a new path object. A "width" 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 column -0.5 <= x < width+0.5 and y>=-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.

## HOME PAGE

<http://user42.tuxfamily.org/math-planepath/index.html>

## LICENSE

Copyright 2010, 2011, 2012, 2013, 2014, 2015, 2016 Kevin Ryde

This file is part of Math-PlanePath.

Math-PlanePath 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.

Math-PlanePath 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 Math-PlanePath. If not, see <http://www.gnu.org/licenses/>.