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Grid-Transform-0.09
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/ Grid::Transform

NAME

Grid::Transform - fast grid transformations

SYNOPSIS

    use Grid::Transform;

    $g = Grid::Transform->new(['a'..'o'], rows=>5);
    $g->rotate_270->flip_vertical;
    print join(' ', $g->grid), "\n";

DESCRIPTION

The Grid::Transform module provides fast methods to transform a grid of arbitrary data types.

METHODS

$g = Grid::Transform->new(\@grid, rows=>num, columns=>num)

Creates a new Grid::Transform object. The first argument is a reference to a 1-dimensional array representing a 2-dimensional "row major" (row by row) grid. (A column major grid is simply the counter transpose of a row major one.) The grid may be composed of arbitrary data types. The original array is never modified- all transformations operate on a copy.

At least one dimension must be specified. If the grid and dimensions do not produce a rectangular grid extra empty elements ("") will be added to the grid.

$g2 = $g->copy

Returns a copy of the original Grid::Transform object.

These methods get or set the grid attributes:

@grid = $g->grid
$grid = $g->grid
@grid = $g->grid(\@grid)

In list context, returns an array representing the current grid. In scalar context, returns a reference to the array. Accepts an array reference representing a new grid. The new grid will be resized if the dimensions of the previous grid do not match.

$g->rows
$g->rows($num)

Returns or sets the current number of rows.

$g->columns
$g->cols
$g->columns($num)

Returns or sets the current number of columns.

All transform methods return the Grid::Transform object, so transforms can be chained.

$g->rotate_90
$g->rotate90

Rotates the grid 90 degrees clock-wise.

    a b c d e f g h i j k l    a b c d      i e a
              |                e f g h  ->  j f b
    i e a j f b k g c l h d    i j k l      k g c
                                            l h d
$g->rotate_180
$g->rotate180

Rotates the grid 180 degrees clock-wise.

    a b c d e f g h i j k l    a b c d      l k j i
              |                e f g h  ->  h g f e
    l k j i h g f e d c b a    i j k l      d c b a
$g->rotate_270
$g->rotate270

Rotates the grid 270 degrees clock-wise.

    a b c d e f g h i j k l    a b c d      d h l
              |                e f g h  ->  c g k
    d h l c g k b f j a e i    i j k l      b f j
                                            a e i
$g->flip_horizontal
$g->mirror_horizontal

Flips the grid across the horizontal axis.

    a b c d e f g h i j k l    a b c d      i j k l
              |                e f g h  ->  e f g h
    i j k l e f g h a b c d    i j k l      a b c d
$g->flip_vertical
$g->mirror_vertical

Flips the grid across the vertical axis.

    a b c d e f g h i j k l    a b c d      d c b a
              |                e f g h  ->  h g f e
    d c b a h g f e l k j i    i j k l      l k j i
$g->transpose

Flips the grid across the vertical axis and then rotates it 90 degress clock-wise.

    a b c d e f g h i j k l    a b c d      l h d
              |                e f g h  ->  k g c
    l h d k g c j f b i e a    i j k l      j f b
                                            i e a
$g->counter_transpose
$g->countertranspose

Flips the grid across the horizontal axis and then rotates it 90 degrees clock-wise.

    a b c d e f g h i j k l    a b c d      a e i
              |                e f g h  ->  b f j
    a e i b f j c g k d h l    i j k l      c g k
                                            d h l
$g->fold_right

Folds the columns to the right.

    a b c d e f g h i j k l    a b c d      b c d a
              |                e f g h  ->  f g e h
    b c a d f g e h j k i l    i j k l      j k i l
$g->fold_left

Folds the columns to the left.

    a b c d e f g h i j k l    a b c d      d a c b
              |                e f g h  ->  h e g f
    d a c b h e g f l i k j    i j k l      l i k j
$g->alternate_row_direction
$g->alt_row_dir

Follows a path from left to right on the first row, right to left on the second, left to right on the third, etc.

    a b c d e f g h i j k l    a b c d      a b c d
              |                e f g h  ->  h g f e
    a b c d h g f e i j k l    i j k l      i j k l
$g->spiral

Follows a spiral path towards the center, starting from the upper left to right.

    a b c d e f g h i j k l    a b c d      a b c d
              |                e f g h  ->  h l k j
    a b c d h l k j i e f g    i j k l      i e f g

NOTES

Some of the methods require temporary extra space for bookkeeping, so it's possible that O(n^3) space will be required- the original array, the internal copy, and the temporary space required by the transformation. Note, the copies are shallow, so they will be smaller than the original array if it contains complex data structures.

REQUESTS AND BUGS

Please report any bugs or feature requests to http://rt.cpan.org/Public/Bug/Report.html?Queue=Grid-Transform. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

TODO

  • Allow the empty element to be user-specified (e.g. $Grid::Transform::EMPTY_ELEMENT or empty_element constructor arg).

  • Accept / convert grid to LoLs.

SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc Grid::Transform

You can also look for information at:

COPYRIGHT AND LICENSE

Copyright (C) 2006-2014 gray <gray at cpan.org>, all rights reserved.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

AUTHOR

gray, <gray at cpan.org>