Math::PlanePath::Columns(3pm)

Usage

 use Math::PlanePath::Columns;
 my $path = Math::PlanePath::Columns->new;
 my ($x, $y) = $path->n_to_xy (123);

Overview

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 zero-based.

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.

Home page

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

Releases

6 releases since Debian 8 (Jessie); the text changed 3 times.