Jeffrey Hayes Anderson

NAME

Math::Window2Viewport - Just another window to viewport mapper.

SYNOPSIS

  use Math::Window2Viewport;

  my $mapper = Math::Window2Viewport->new(
      Wb => 0, Wt => 1, Wl => 0, Wr => 1,
      Vb => 9, Vt => 0, Vl => 0, Vr => 9,
  );

  my ($x, $y) = (0.5, 0.6);
  my $x2 = int( $mapper->Dx( $x ) );
  my $y2 = int( $mapper->Dy( $y ) );

DESCRIPTION

This module will convert one set of coordinates (the World Window) into another set (the Viewport) for the purposes of graphing any set of points from one system to another.

METHODS

  • new()

    Constructs object. Required parameters:

             Wt                  Vt
        +----------+       +------------+
        |          |       |            |
      Wl|  window  |Wr   Vl|  viewport  |Vr
        |          |       |            |
        +----------+       +------------+
             Wb                  Vb
  • Wb

      world window bottom
  • Wt

      world window top
  • Wl

      world window left
  • Wr

      world window right
  • Vb

      viewport bottom
  • Vt

      viewport top
  • Vl

      viewport left
  • Vr

      viewport right
  • Dx( x )

    Calculates new point Dx for given point x. Client is responsible for casting value to int.

  • Dy( y )

    Calculates new point Dy for given point y. Client is responsible for casting value to int.

EXAMPLE

The following will generate a Fourier synthesized square wave via GD::Simple:

  use GD::Simple;
  use Math::Window2Viewport;

  my ($width, $height, $res) = (500, 300, .02);
  my $img = GD::Simple->new( $width, $height );
  my $mapper = Math::Window2Viewport->new(
      Wb => -1, Wt => 1, Wl => -1, Wr => 1,
      Vb => $height, Vt => 0, Vl => 0, Vr => $width,
  );

  my (%curr,%prev);
  for (my $x = -1; $x <= 1; $x += $res) {
      my $y = 0;
      for (my $i = 1; $i < 20; $i += 2) {
          $y += 1 / $i * cos( 2 * 3.1459 * $i * $x + ( -3.1459 / 2 ) );
      }
      %curr = ( dx => $mapper->Dx( $x ), dy => $mapper->Dy( $y ) );
      $img->moveTo( @prev{qw(dx dy)} );
      $img->lineTo( @curr{qw(dx dy)} );
      %prev = %curr;
  }

  print $img->png;

Try changing the value for $res. See the example directory for more.

RENDERED EXAMPLES

Bar chart

Sine wave

Sawtooth wave

Triangle wave

Square wave

Fourier square

SEE ALSO

AUTHOR

Jeff Anderson, <jeffa at cpan.org>

LICENSE AND COPYRIGHT

Copyright 2017 Jeff Anderson.

This program is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0). You may obtain a copy of the full license at:

http://www.perlfoundation.org/artistic_license_2_0

Any use, modification, and distribution of the Standard or Modified Versions is governed by this Artistic License. By using, modifying or distributing the Package, you accept this license. Do not use, modify, or distribute the Package, if you do not accept this license.

If your Modified Version has been derived from a Modified Version made by someone other than you, you are nevertheless required to ensure that your Modified Version complies with the requirements of this license.

This license does not grant you the right to use any trademark, service mark, tradename, or logo of the Copyright Holder.

This license includes the non-exclusive, worldwide, free-of-charge patent license to make, have made, use, offer to sell, sell, import and otherwise transfer the Package with respect to any patent claims licensable by the Copyright Holder that are necessarily infringed by the Package. If you institute patent litigation (including a cross-claim or counterclaim) against any party alleging that the Package constitutes direct or contributory patent infringement, then this Artistic License to you shall terminate on the date that such litigation is filed.

Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES. THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT ARE DISCLAIMED TO THE EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS REQUIRED BY LAW, NO COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT OF THE USE OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.