debian man page for math::gradient

Gradient(3pm)						User Contributed Perl Documentation					     Gradient(3pm)

NAME
       Math::Gradient - Perl extension for calculating gradients for colour transitions, etc.

SYNOPSIS
       use Math::Gradient qw(multi_gradient);

       # make a 100-point colour palette to smothly transition between 6 RGB values

       my(@hot_spots) = ([ 0, 255, 0 ], [ 255, 255, 0 ], [ 127, 127, 127 ], [ 0, 0, 255 ], [ 127, 0, 0 ], [ 255, 255, 255 ]);

       my(@gradient) = multi_array_gradient(100, @hot_spots);

DESCRIPTION
       Math::Gradient is used to calculate smooth transitions between numerical values (also known as a "Gradient"). I wrote this module mainly to
       mix colours, but it probably has several other applications. Methods are supported to handle both basic and multiple-point gradients, both
       with scalars and arrays.

FUNCTIONS
       gradient($start_value, $end_value, $steps)
	   This function will return an array of evenly distributed values between $start_value and $end_value. All three values supplied should
	   be numeric. $steps should be the number of steps that should occur  between the two points; for instance, gradient(0, 10, 4) would
	   return the array (2, 4, 6, 8); the 4 evenly-distributed steps necessary to get from 0 to 10, whereas gradient(0, 1, 3) would return
	   (0.25, 0.5, 0.75). This is the basest function in the Math::Gradient module and isn't very exciting, but all of the other functions
	   below derive their work from it.

       array_gradient($start_value, $end_value, $steps)
	   While gradient() takes numeric values for $start_value and $end_value, array_gradient() takes arrayrefs instead. The arrays supplied
	   are expected to be lists of numerical values, and all of the arrays should contain the same number of elements. array_gradient() will
	   return a list of arrayrefs signifying the gradient of all values on the lists $start_value and $end_value.

	   For example, calling array_gradient([ 0, 100, 2 ], [ 100, 50, 70], 3) would return: ([ 25, 87.5, 19 ], [ 50, 75, 36 ], [ 75, 62.5, 53
	   ]).

       multi_gradient($steps, @values)
	   multi_gradient() calculates multiple gradients at once, returning one list that is an even transition between all points, with the
	   values supplied interpolated evenly within the list. If $steps is less than the number of entries in the list @values, items are
	   deleted from @values instead.

	   For example, calling multi_gradient(10, 0, 100, 50) would return: (0, 25, 50, 75, 100, 90, 80, 70, 60, 50)

       multi_array_gradient($steps, @values)
	   multi_array_gradient() is the same as multi_gradient, except that it works on arrayrefs instead of scalars (like array_gradient() is to
	   gradient()).

AUTHOR
       Tyler MacDonald, <japh@crackerjack.net>

COPYRIGHT AND LICENSE
       Copyright 2003 by Tyler MacDonald

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

perl v5.10.1							    2010-03-12							     Gradient(3pm)