Spaces:
Sleeping
Sleeping
File size: 8,423 Bytes
9a14526 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 | 'use strict';
module.exports = Point;
/**
* A standalone point geometry with useful accessor, comparison, and
* modification methods.
*
* @class Point
* @param {Number} x the x-coordinate. this could be longitude or screen
* pixels, or any other sort of unit.
* @param {Number} y the y-coordinate. this could be latitude or screen
* pixels, or any other sort of unit.
* @example
* var point = new Point(-77, 38);
*/
function Point(x, y) {
this.x = x;
this.y = y;
}
Point.prototype = {
/**
* Clone this point, returning a new point that can be modified
* without affecting the old one.
* @return {Point} the clone
*/
clone: function() { return new Point(this.x, this.y); },
/**
* Add this point's x & y coordinates to another point,
* yielding a new point.
* @param {Point} p the other point
* @return {Point} output point
*/
add: function(p) { return this.clone()._add(p); },
/**
* Subtract this point's x & y coordinates to from point,
* yielding a new point.
* @param {Point} p the other point
* @return {Point} output point
*/
sub: function(p) { return this.clone()._sub(p); },
/**
* Multiply this point's x & y coordinates by point,
* yielding a new point.
* @param {Point} p the other point
* @return {Point} output point
*/
multByPoint: function(p) { return this.clone()._multByPoint(p); },
/**
* Divide this point's x & y coordinates by point,
* yielding a new point.
* @param {Point} p the other point
* @return {Point} output point
*/
divByPoint: function(p) { return this.clone()._divByPoint(p); },
/**
* Multiply this point's x & y coordinates by a factor,
* yielding a new point.
* @param {Point} k factor
* @return {Point} output point
*/
mult: function(k) { return this.clone()._mult(k); },
/**
* Divide this point's x & y coordinates by a factor,
* yielding a new point.
* @param {Point} k factor
* @return {Point} output point
*/
div: function(k) { return this.clone()._div(k); },
/**
* Rotate this point around the 0, 0 origin by an angle a,
* given in radians
* @param {Number} a angle to rotate around, in radians
* @return {Point} output point
*/
rotate: function(a) { return this.clone()._rotate(a); },
/**
* Rotate this point around p point by an angle a,
* given in radians
* @param {Number} a angle to rotate around, in radians
* @param {Point} p Point to rotate around
* @return {Point} output point
*/
rotateAround: function(a,p) { return this.clone()._rotateAround(a,p); },
/**
* Multiply this point by a 4x1 transformation matrix
* @param {Array<Number>} m transformation matrix
* @return {Point} output point
*/
matMult: function(m) { return this.clone()._matMult(m); },
/**
* 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.
* @return {Point} unit vector point
*/
unit: function() { return this.clone()._unit(); },
/**
* 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
* @return {Point} perpendicular point
*/
perp: function() { return this.clone()._perp(); },
/**
* Return a version of this point with the x & y coordinates
* rounded to integers.
* @return {Point} rounded point
*/
round: function() { return this.clone()._round(); },
/**
* Return the magitude of this point: this is the Euclidean
* distance from the 0, 0 coordinate to this point's x and y
* coordinates.
* @return {Number} magnitude
*/
mag: function() {
return Math.sqrt(this.x * this.x + this.y * this.y);
},
/**
* Judge whether this point is equal to another point, returning
* true or false.
* @param {Point} other the other point
* @return {boolean} whether the points are equal
*/
equals: function(other) {
return this.x === other.x &&
this.y === other.y;
},
/**
* Calculate the distance from this point to another point
* @param {Point} p the other point
* @return {Number} distance
*/
dist: function(p) {
return Math.sqrt(this.distSqr(p));
},
/**
* Calculate the distance from this point to another point,
* without the square root step. Useful if you're comparing
* relative distances.
* @param {Point} p the other point
* @return {Number} distance
*/
distSqr: function(p) {
var dx = p.x - this.x,
dy = p.y - this.y;
return dx * dx + dy * dy;
},
/**
* Get the angle from the 0, 0 coordinate to this point, in radians
* coordinates.
* @return {Number} angle
*/
angle: function() {
return Math.atan2(this.y, this.x);
},
/**
* Get the angle from this point to another point, in radians
* @param {Point} b the other point
* @return {Number} angle
*/
angleTo: function(b) {
return Math.atan2(this.y - b.y, this.x - b.x);
},
/**
* Get the angle between this point and another point, in radians
* @param {Point} b the other point
* @return {Number} angle
*/
angleWith: function(b) {
return this.angleWithSep(b.x, b.y);
},
/*
* Find the angle of the two vectors, solving the formula for
* the cross product a x b = |a||b|sin(θ) for θ.
* @param {Number} x the x-coordinate
* @param {Number} y the y-coordinate
* @return {Number} the angle in radians
*/
angleWithSep: function(x, y) {
return Math.atan2(
this.x * y - this.y * x,
this.x * x + this.y * y);
},
_matMult: function(m) {
var x = m[0] * this.x + m[1] * this.y,
y = m[2] * this.x + m[3] * this.y;
this.x = x;
this.y = y;
return this;
},
_add: function(p) {
this.x += p.x;
this.y += p.y;
return this;
},
_sub: function(p) {
this.x -= p.x;
this.y -= p.y;
return this;
},
_mult: function(k) {
this.x *= k;
this.y *= k;
return this;
},
_div: function(k) {
this.x /= k;
this.y /= k;
return this;
},
_multByPoint: function(p) {
this.x *= p.x;
this.y *= p.y;
return this;
},
_divByPoint: function(p) {
this.x /= p.x;
this.y /= p.y;
return this;
},
_unit: function() {
this._div(this.mag());
return this;
},
_perp: function() {
var y = this.y;
this.y = this.x;
this.x = -y;
return this;
},
_rotate: function(angle) {
var cos = Math.cos(angle),
sin = Math.sin(angle),
x = cos * this.x - sin * this.y,
y = sin * this.x + cos * this.y;
this.x = x;
this.y = y;
return this;
},
_rotateAround: function(angle, p) {
var cos = Math.cos(angle),
sin = Math.sin(angle),
x = p.x + cos * (this.x - p.x) - sin * (this.y - p.y),
y = p.y + sin * (this.x - p.x) + cos * (this.y - p.y);
this.x = x;
this.y = y;
return this;
},
_round: function() {
this.x = Math.round(this.x);
this.y = Math.round(this.y);
return this;
}
};
/**
* Construct a point from an array if necessary, otherwise if the input
* is already a Point, or an unknown type, return it unchanged
* @param {Array<Number>|Point|*} a any kind of input value
* @return {Point} constructed point, or passed-through value.
* @example
* // this
* var point = Point.convert([0, 1]);
* // is equivalent to
* var point = new Point(0, 1);
*/
Point.convert = function (a) {
if (a instanceof Point) {
return a;
}
if (Array.isArray(a)) {
return new Point(a[0], a[1]);
}
return a;
};
|