polygon-generator
API
polygon = require('polygon-generator');coordinates method
Calculate coordinates of an equilateral polygon. The returned object is an array of the following structure:
[{x: 0, y: 0}, {x: 1, y: 0}, {x: 0.5, y: 0.866}]The vectors form an anti-clockwise path with the last vector connecting back to the first one. All coordinates will be in the first quadrant of a cartesian coordinate system meaning there will be no negative numbers. This method takes three parameters:
- sides: the number of sides of the polygon (minimum is 3)
- sideLength: the length of each side (default is 1)
- startingAngle: determines the angle of the first edge, rotates anti-clockwise (default is 0, horizontal line)
sides = 3;
sideLength = 1;
startingAngle = 10;
vertices = polygon.coordinates(sides, sideLength, startingAngle);polygon wrapper
The polygon object provides translation, rotation and scaling methods for polygons. To create one simply pass in an array of vectors representing the vertices.
poly = polygon.polygon([{x: 0, y: 0}, {x: 1, y: 0}, {x: 0.5, y: 0.866}]);You can also directly pass in the results of the coordinates method.
poly = polygon.polygon(polygon.coordinates(5,2,20));translate
poly.translate(vector);Translate shifts a polygon along a vector. The vector needs to be an object with a field x and y, which should both be numbers.
rotate
poly.rotate(angle, point);Rotate a polygon anti-clockwise around a given point {x: ?, y: ?} by the specified angle. If no point is specified then the centroid of the polygon will be used.
scale
poly.rotate(factor, point);Scale a polygon by a certain factor with regard to a given point. If no point is specified then the centroid of the polygon will be used.
area
poly.area();Returns the area of the polygon.
centroid
poly.centroid();Returns the coordinates of the centroid {x: Cx, y: Cy}.