### 5 releases (breaking)

0.5.0 | Feb 6, 2023 |
---|---|

0.4.0 | Feb 5, 2023 |

0.3.0 | Feb 4, 2023 |

0.2.0 | Jan 25, 2023 |

0.1.0 | Jan 24, 2023 |

#**724** in Math

**135** downloads per month

Used in esvg

**MIT**license

38KB

886 lines

# Polygonical

A library for interacting with polygons on a 2d plane.

## Examples

Rotate a polygon:

` ``use` `polygonical``::``polygon``::`Polygon`;`
`use` `polygonical``::``point``::`Point`;`
`let` poly `=` `Polygon``::`new`(``vec!``[`
`Point``::`new`(``0.``0``,` `1.``0``)``,`
`Point``::`new`(``1.``0``,` `1.``0``)``,`
`Point``::`new`(``1.``0``,` `0.``0``)``,`
`]``)``;`
`//` get the area of the polygon
`let` area `=` poly`.``area``(``)``;`
`//` rotate the polygon around its own center by 90 degrees
`let` rotated `=` poly`.``rotate_around_center``(``90.``0_``f64``.``to_radians``(``)``)``;`
`println!``(``"`area: `{}` rotated: `{}``"``,` area`,` rotated`)``;`

Create an approximation of a circle:

` ``use` `polygonical``::``polygon``::`Polygon`;`
`use` `polygonical``::``point``::`Point`;`
`let` num_points `=` `16``;`
`let` radius `=` `2.``0``;`
`let` center `=` `Point``::`new`(``10.``0``,` `20.``0``)``;`
`//` Note: we use an integer number of degrees here because rust won't let you iterate over floats like this.
`let` points `=` `(``0``..``360``)``.``step_by``(``360``/`num_points`)`
`.``map``(``|``a``|` `Point``::`new`(`radius`,` `0.``0``)``.``rotate``(``(`a `as` `f64``)``.``to_radians``(``)``)``.``translate``(``&`center`)``)`
`.``collect``(``)``;`
`let` circle `=` `Polygon``::`new`(`points`)``;`
`let` approx_area `=` circle`.``area``(``)``;`
`let` area `=` `std``::``f64``::``consts``::``PI` `*` radius `*` radius`;`
`println!``(``"`area: `{}` aprox_area: `{}` difference: `{}``"``,` area`,` approx_area`,` area `-` approx_area`)``;`

## Features

- Points
- Polygons
- Bounding boxes
- Translations of points
- Polygons contain points
- Polygon is_self_intersecting
- Polygon area
- Translations of polygons
- Rotations of points
- Rotations of polygons
- Overlap detection
- Contains detection
- Polygon unions

## Wanted Features

Things we want to implement but haven't yet.

- Scale of points
- Scale of polygons
- Polygon subtraction

## Unwanted Features

Things this library won't do.

- 3d Geometry
- Output to things like svg (that is for another library)
- Coordinate system transforms, epsg codes, pixel space to world space etc.

## Design goals

- Correct
- Safe
- Fast

In that order

## Limitations / Warnings

Polygons must be specified with the points going clockwise around them. Several algorithms only work when points are defined clockwise. There is no detection of this, it will probably cause weird results, it has not been tested.

#### Dependencies

~45KB