- constructor:
- Polygon - create a polygon instance
- polygon structural manipulation:
- remove - remove vertices given at certain indexes
- splice - remoce vertices found within two given indexes
- slice - return a new polygon built with vertices found within two given indexes
- push - push a new vertices at the end of the polygon
- unshift - push a new vertices at the begining of the polygon
- shift - retrive and remove first vertex
- pop - retrive and remove last vertex
- change - change a given vertex
- swap - swap between polygon X and Y properties
- append - append a given polygon at the end of current polygon
- insertPolygon - insert a polygon in a given index
- insertVertex - insert a vertex in a given index
- reverse - reverse polygon vertices
- sortCW - sort polygon vertices clockwise
- polygon information extraction
- getX - return an array of vertices X part
- getY - return an array of vertices Y part
- vertices - return two arrays of vertices location (X, Y)
- size - return number of vertices in polygon
- data - return polygon area, perimeter, centeroid, moments of inertia and centroidal moments of inertia
- isClockWise - return true if polygon vertices are sorted clock wise
- maxSide - return index of first vertices (and the following vertices) whos side is largest, and that side value
- minSide - return index of first vertices (and the following vertices) whos side is smallest, and that side value
- maxAngle - return index of first vertices whos angle is smallest (sharpest edge) and that angle value
- minAngle - return index of first vertices whos angle is largest (widest edge) and thath angle value
- extent - return the bounding box of polygon [Xmin, Xmax, Ymin, Ymax] (not necessarily the minimal bounding box)
- bottomVertex - return index of lowest vertex
- upperVertex - return index of highest vertex
- leftVertex - return index of "left-most" vertex
- rightVertex - return index of "right-most" vertex
- polygon geometric manipulation:
- rotate - rotate polygon certain degrees around a given point
- moveAlong - move polygon certain distance along a given directions
- moveBy - move polygon certain distance along the X and Y axis
- simplify - remove "reduceable" (= "less important") vertices
- sliceBox - remove all polygon vertices located within a given box [bottom left, upper right]
- sliceCircle - remove all polygon vertices located within a given circle [x, y, radius]
- polygon-point operation / information:
- inside - test if a given point is located within the polygon
- on - test if a given point is located on the polygon
- closest - return the polygon vertices closest to a given point
- polygon-line operation / information:
- lineIntersect - return a flag indicating if a line intersects the polygon and a set of (x,y) intersection points
- polygon-polygon operation / information:
- intersect - perform intersection between two polygons (clipping polygon must be convex)
- union - perform union between two polygons (clipping polygon must be convex)
- isEqual - return true if two polygons are equal
- other methods:
- toString - return polygon as a human readable string
- convexHull - return a polygon which is the convex hull of current polygon
- radialFit - approximate polygon as a circle or an ellipse
- accuracy - used to determine floating point equality tolerance default: 1e-10
- Polygon is always closed. Last vertex is connected to first vertex.
- Boolean operation (union, intersect) are allowed only if the "clipping" polygon is convex.
- methods convexHull and Simplify utilize recrusive functions.
- Polygon class use 'privileged' methods (a term used to describe closures within the constructor).
- The following polygon operations can be chained: remove, splice, push, unshift, change, swap, append, insertPolygon, insertVertex, reverse, sortCW, sliceBox, sliceCircle, rotate, moveAlong, moveBy, simplify.
// create a star shaped polygon composed of 100 points
var _star = new Polygon({type: 'star', inner: 100, outer: 300, points: 100});
// remove all its 'inner circle' vertex and move it 50px to the right
_star.sliceCircle(0, 0, 200).moveBy(50, 0);
// fit a circle
var _circleFit = _star.radialFit('circle');
// check fitted circle error
console.log('fitted circle radius error is ' + (_circleFit[2] - 300) + '.\n' +
'fitted circle origin error in x is ' + (_circleFit[0] - 50) + '.\n' +
'fitted circle origin error in y is ' + (_circleFit[1]) + '.\n'); // create a hexagon
var _hex = new Polygon({type: 'regular', radius: 100, points: 6});
// rotate hexagon by 70 degrees and move it 95px in a 45 degrees bearing
_hex.rotate(0, 0, 70).moveAlong(45, 95);
// create a circle
var _circ = new Polygon({type: 'circle', radius: 45, points: 50});
// move circle 110px to the right
_circ.moveBy(110, 0);
// calcute circle and hexagon intersection
var _intersect = _hex.intersect(_circ);
// extract intersection geometrical properties
var _data = _intersect.data();
// console.log();
console.log('intersection polygon centeroid is (' + _data[0] + ', ' + _data[1] + ')\n' +
'intersection polygon perimeter is ' + _data[2] + '\n' +
'intersection polygon Ixx is ' + _data[3] + '\n' +
'intersection polygon Iyy is ' + _data[4] + '\n' +
'intersection polygon Ixy is ' + _data[5] + '\n' +
'intersection polygon centeroidal Ixx is ' + _data[6] + '\n' +
'intersection polygon centeroidal Iyy is ' + _data[7] + '\n' +
'intersection polygon centeroidal Ixy is ' + _data[8]); // create two polygons
var subject = new Polygon({type: 'point', points: [[50, 150], [200, 50], [350, 150], [350, 300], [250, 300], [200, 250], [150, 350], [100, 250], [100, 200]]}),
cliper = new Polygon({type: 'point', points: [[100, 100], [300, 100], [300, 300], [100, 300]]});
// calculate their union
union = subject.union(cliper);