---
name: "Math::PlanePath::Rows"
section: "3pm"
platform: "linux"
package: "libmath-planepath-perl"
version: "129-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Math::PlanePath::Rows"
---

# Math::PlanePath::Rows(3pm)

## NAME

Math::PlanePath::Rows -- 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.

## SEE ALSO

Math::PlanePath, Math::PlanePath::Columns

## HOME PAGE

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

## LICENSE

Copyright 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 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/\>.