point-geometry

a point geometry with transforms

Point(x, y)

A standalone point geometry with useful accessor, comparison, and modification methods.

Parameters

| parameter | type | description | | --------- | ------ | -------------------------------------------------------------------------------------- | | x | Number | the x-coordinate. this could be longitude or screen pixels, or any other sort of unit. | | y | Number | the y-coordinate. this could be latitude or screen pixels, or any other sort of unit. |

Example

var point = new Point(-77, 38);

clone

Clone this point, returning a new point that can be modified without affecting the old one.

Returns Point, the clone

add(p)

Add this point's x & y coordinates to another point, yielding a new point.

Parameters

| parameter | type | description | | --------- | ----- | --------------- | | p | Point | the other point |

Returns Point, output point

sub(p)

Subtract this point's x & y coordinates to from point, yielding a new point.

Parameters

| parameter | type | description | | --------- | ----- | --------------- | | p | Point | the other point |

Returns Point, output point

multByPoint(p)

Multiply this point's x & y coordinates by point, yielding a new point.

Parameters

| parameter | type | description | | --------- | ----- | --------------- | | p | Point | the other point |

Returns Point, output point

divByPoint(p)

Divide this point's x & y coordinates by point, yielding a new point.

Parameters

| parameter | type | description | | --------- | ----- | --------------- | | p | Point | the other point |

Returns Point, output point

mult(k)

Multiply this point's x & y coordinates by a factor, yielding a new point.

Parameters

| parameter | type | description | | --------- | ----- | ----------- | | k | Point | factor |

Returns Point, output point

div(k)

Divide this point's x & y coordinates by a factor, yielding a new point.

Parameters

| parameter | type | description | | --------- | ----- | ----------- | | k | Point | factor |

Returns Point, output point

rotate(a)

Rotate this point around the 0, 0 origin by an angle a, given in radians

Parameters

| parameter | type | description | | --------- | ------ | ---------------------------------- | | a | Number | angle to rotate around, in radians |

Returns Point, output point

rotateAround(a, p)

Rotate this point around p point by an angle a, given in radians

Parameters

| parameter | type | description | | --------- | ------ | ---------------------------------- | | a | Number | angle to rotate around, in radians | | p | Point | Point to rotate around |

Returns Point, output point

matMult(m)

Multiply this point by a 4x1 transformation matrix

Parameters

| parameter | type | description | | --------- | ----------------- | --------------------- | | m | Array.<Number> | transformation matrix |

Returns Point, output point

unit

Calculate this point but as a unit vector from 0, 0, meaning that the distance from the resulting point to the 0, 0 coordinate will be equal to 1 and the angle from the resulting point to the 0, 0 coordinate will be the same as before.

Returns Point, unit vector point

perp

Compute a perpendicular point, where the new y coordinate is the old x coordinate and the new x coordinate is the old y coordinate multiplied by -1

Returns Point, perpendicular point

round

Return a version of this point with the x & y coordinates rounded to integers.

Returns Point, rounded point

mag

Return the magitude of this point: this is the Euclidean distance from the 0, 0 coordinate to this point's x and y coordinates.

Returns Number, magnitude

equals(other)

Judge whether this point is equal to another point, returning true or false.

Parameters

| parameter | type | description | | --------- | ----- | --------------- | | other | Point | the other point |

Returns boolean, whether the points are equal

dist(p)

Calculate the distance from this point to another point

Parameters

| parameter | type | description | | --------- | ----- | --------------- | | p | Point | the other point |

Returns Number, distance

distSqr(p)

Calculate the distance from this point to another point, without the square root step. Useful if you're comparing relative distances.

Parameters

| parameter | type | description | | --------- | ----- | --------------- | | p | Point | the other point |

Returns Number, distance

angle

Get the angle from the 0, 0 coordinate to this point, in radians coordinates.

Returns Number, angle

angleTo(b)

Get the angle from this point to another point, in radians

Parameters

| parameter | type | description | | --------- | ----- | --------------- | | b | Point | the other point |

Returns Number, angle

angleWith(b)

Get the angle between this point and another point, in radians

Parameters

| parameter | type | description | | --------- | ----- | --------------- | | b | Point | the other point |

Returns Number, angle

angleWithSep(x, y)

Find the angle of the two vectors, solving the formula for the cross product a x b = |a||b|sin(θ) for θ.

Parameters

| parameter | type | description | | --------- | ------ | ---------------- | | x | Number | the x-coordinate | | y | Number | the y-coordinate |

Returns Number, the angle in radians

convert(a)

Construct a point from an array if necessary, otherwise if the input is already a Point, or an unknown type, return it unchanged

Parameters

| parameter | type | description | | --------- | ------------------------ | ----------------------- | | a | Array.<Number>,Point | any kind of input value |

Example

// this
var point = Point.convert([0, 1]);
// is equivalent to
var point = new Point(0, 1);

Returns Point, constructed point, or passed-through value.

Installation

Requires nodejs.

$ npm install point-geometry

Tests

$ npm test