Geometry for Ruby
=================

[![Build Status](https://travis-ci.org/bfoz/geometry.png)](https://travis-ci.org/bfoz/geometry)

Classes and methods for the handling of all of the basic geometry that you 
learned in high school (and then forgot).

The classes in this libary are based on the Vector class provided by the Ruby 
standard library. Geometric primitives are generally assumed to lie in 2D space,
but aren't necessarily restricted to it. Please let me know if you find cases 
that don't work in higher dimensions and I'll do my best to fix them.

License
-------

Copyright 2012-2014 Brandon Fosdick <bfoz@bfoz.net> and released under the BSD license.

Primitives
----------

- Point
- Size
- Line
- Edge
- [Arc](http://en.wikipedia.org/wiki/Arc_(geometry)), Circle
- Rectangle, Square
- Path, [Polyline](http://en.wikipedia.org/wiki/Polyline), [Polygon](http://en.wikipedia.org/wiki/Polygon), [RegularPolygon](http://en.wikipedia.org/wiki/Regular_polygon)
- Transformation
- [Triangle](http://en.wikipedia.org/wiki/Triangle)
- [Obround](http://en.wiktionary.org/wiki/obround)

Examples
--------

### Point
```ruby
    point = Geometry::Point[3,4]    # 2D Point at coordinate 3, 4

    # Copy constructors
    point2 = Geometry::Point[point]
    point2 = Geometry::Point[Vector[5,6]]

    # Accessors
    point.x
    point.y
    point[2]	# Same as point.z

    # Zero
    PointZero.new   # A Point full of zeros of unspecified length
    Point.zero      # Another way to do the same thing
    Point.zero(3)   # => Point[0,0,0]
```

### Line
```ruby
    # Two-point constructors
    line = Geometry::Line[[0,0], [10,10]]
    line = Geometry::Line[Geometry::Point[0,0], Geometry::Point[10,10]]
    line = Geometry::Line[Vector[0,0], Vector[10,10]]

    # Slope-intercept constructors
    Geometry::Line[Rational(3,4), 5]	# Slope = 3/4, Intercept = 5
    Geometry::Line[0.75, 5]

    # Point-slope constructors
    Geometry::Line(Geometry::Point[0,0], 0.75)
    Geometry::Line(Vector[0,0], Rational(3,4))

    # Special constructors (2D only)
    Geometry::Line.horizontal(y=0)
    Geometry::Line.vertical(x=0)
```

### Rectangle
```ruby
    # A Rectangle made from two corner points
    Geometry::Rectangle.new [1,2], [2,3]
    Geometry::Rectangle.new from:[1,2], to:[2,3]

    Geometry::Rectangle.new center:[1,2], size:[1,1]	# Using a center point and a size
    Geometry::Rectangle.new origin:[1,2], size:[1,1]	# Using an origin point and a size

    # A Rectangle with its origin at [0, 0] and a size of [10, 20]
    Geometry::Rectangle.new size: [10, 20]
    Geometry::Rectangle.new size: Size[10, 20]
    Geometry::Rectangle.new width: 10, height: 20
```

### Circle
```ruby
    # A circle at Point[1,2] with a radius of 3
    circle = Geometry::Circle.new center:[1,2], radius:3
```

### Polygon
```ruby
    # A polygon that looks a lot like a square
    polygon = Geometry::Polygon.new [0,0], [1,0], [1,1], [0,1]
```
### Regular Polygon
```ruby
    # Everyone loves a good hexagon
    hexagon = Geometry::RegularPolygon.new 6, :diameter => 3
```