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.

HOME PAGE

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

LICENSE

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/>.

2018-03-18

perl v5.26.1