/ 
Term-Fabulous-0.01
/ Term::Fabulous::Chart::Scale::Linear

NAME

Term::Fabulous::Chart::Scale::Linear - A numeric axis with evenly spaced ticks

SYNOPSIS

use Term::Fabulous::Chart::Scale::Linear;

# A vertical axis of 17 rows for data from 3 to 97:
my $scale = Term::Fabulous::Chart::Scale::Linear->fit( extent => [ 3, 97 ], cells => 17 );
say join ' ', map { $_->{label} } $scale->ticks;    # 0 25 50 75 100
say $scale->used;                                   # 17: a tick every 4 rows

DESCRIPTION

A Term::Fabulous::Chart::Scale for numbers. "fit" chooses the domain and the ticks: the ticks are multiples of a nice step (1, 2, 2.5 or 5 times a power of ten), the domain is the data rounded out to the nearest ticks, and the choice balances

  • that the ticks fall on whole cells, so that grid lines lie exactly beside their labels and at the height of the values they name (an axis may then use a few cells less than it has),

  • how much empty room the rounding adds above and below the data,

  • and a comfortable distance between the ticks: about every three to six rows on a vertical axis, and on a horizontal axis far enough apart that the labels do not touch.

CLASS METHODS

fit

my $scale = Term::Fabulous::Chart::Scale::Linear->fit(%options);
cells

The cells the axis has, a positive integer; required.

extent

[ $lowest, $highest ] value of the data; undef for no data (the axis then shows 0 to 1).

min, max

Fixed ends of the domain. A fixed end is not rounded. min must be less than max, or fit dies.

zero

True to include 0 in the domain (bars and areas grow from 0).

orientation

vertical (the default) or horizontal; a horizontal axis spaces its ticks by the width of their labels.

measure

A function returning the columns a label takes; for horizontal axes.

format

The label format (see Term::Fabulous::Chart::Format).

step

A fixed distance between ticks. A step too small for the cells (more intervals across the data than the axis has cells) gives no ticks between the two ends, as when nothing else fits.

ticks

The number of ticks wanted; the closest fitting choice wins.

integer

True when all values are whole numbers: no ticks less than 1 apart (and no steps of 2.5 below 25), so no tick lies between two whole numbers.

nice

False to keep the domain at the data instead of rounding it to ticks.

align

True to choose ticks that fall on whole cells, at the price of a few unused cells at the end of the axis; the default for vertical axes, where every tick has a grid line and a label beside it.

METHODS

Those of Term::Fabulous::Chart::Scale, and step, the distance between two ticks.

SEE ALSO

Term::Fabulous::Chart::Scale.