NAME¶
Math::Polygon::Transform - Polygon transformation
INHERITANCE¶
Math::Polygon::Transform
is a Exporter
SYNOPSIS¶
my @poly = ( [1,2], [2,4], [5,7], [1, 2] );
my $area = polygon_transform resize => 3.14, @poly;
DESCRIPTION¶
This package contains polygon transformation algorithms.
FUNCTIONS¶
- polygon_grid(%options, LIST-of-$points)
- Snap the polygon points to grid points, where artifacts are removed.
-Option--Default
raster 1.0
- raster => FLOAT
- The raster size, which determines the points to round to. The origin
"[0,0]" is always on a grid-point. When the raster value is
zero, no transformation will take place.
- polygon_mirror(%options, LIST-of-$points)
- Mirror the polygon in a line. Only one of the options can be provided.
Some programs call this "flip" or "flop".
-Option--Default
b 0
line <undef>
rc undef
x undef
y undef
- b => FLOAT
- Only used in combination with option "rc" to describe a
line.
- line => [POINT, POINT]
- Alternative way to specify the mirror line. The "rc" and
"b" are computed from the two points of the line.
- rc => FLOAT
- Description of the line which is used to mirror in. The line is "y=
rc*x+b". The "rc" equals "-dy/dx", the firing
angle. If "undef" is explicitly specified then "b" is
used as constant x: it's a vertical mirror.
- x => FLOAT
- Mirror in the line "x=value", which means that "y"
stays unchanged.
- y => FLOAT
- Mirror in the line "y=value", which means that "x"
stays unchanged.
- polygon_move(%options, LIST-of-$points)
- Returns a list of points which are moved over the indicated distance
-Option--Default
dx 0
dy 0
- dx => FLOAT
- Displacement in the horizontal direction.
- dy => FLOAT
- Displacement in the vertical direction.
- polygon_resize(%options, LIST-of-$points)
-
-Option--Default
center [0,0]
scale 1.0
xscale <scale>
yscale <scale>
- center => POINT
- scale => FLOAT
- Resize the polygon with the indicated factor. When the factor is larger
than 1, the resulting polygon with grow, when small it will be reduced in
size. The scale will be respective from the center.
- xscale => FLOAT
- Specific scaling factor in the horizontal direction.
- yscale => FLOAT
- Specific scaling factor in the vertical direction.
- polygon_rotate(%options, LIST-of-$points)
-
-Option --Default
center [0,0]
degrees 0
radians 0
- center => POINT
- degrees => FLOAT
- specify rotation angle in degrees (between -180 and 360).
- radians => FLOAT
- specify rotation angle in rads (between -pi and 2*pi)
- polygon_simplify(%options, LIST-of-$points)
-
-Option --Default
max_points undef
same 0.0001
slope undef
- max_points => INTEGER
- First, "same" and "slope" reduce the number of points.
Then, if there are still more than the specified number of points left,
the points with the widest angles will be removed until the specified
maximum number is reached.
- same => FLOAT
- The distance between two points to be considered "the same"
point. The value is used as radius of the circle.
- slope => FLOAT
- With three points X(n),X(n+1),X(n+2), the point X(n+1) will be removed if
the length of the path over all three points is less than
"slope" longer than the direct path between X(n) and X(n+2).
The slope will not be removed around the starting point of the polygon.
Removing points will change the area of the polygon.
DIAGNOSTICS¶
- Error: you need to specify 'x', 'y', 'rc', or 'line'
SEE ALSO¶
This module is part of Math-Polygon distribution version 1.03, built on January
21, 2014. Website:
http://perl.overmeer.net/geo/
LICENSE¶
Copyrights 2004,2006-2014 by [Mark Overmeer]. For other contributors see
ChangeLog.
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself. See
http://www.perl.com/perl/misc/Artistic.html
