1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/toolkit/modules/Geometry.jsm Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,327 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +this.EXPORTED_SYMBOLS = ["Point", "Rect"];
1.9 +
1.10 +/**
1.11 + * Simple Point class.
1.12 + *
1.13 + * Any method that takes an x and y may also take a point.
1.14 + */
1.15 +this.Point = function Point(x, y) {
1.16 + this.set(x, y);
1.17 +}
1.18 +
1.19 +Point.prototype = {
1.20 + clone: function clone() {
1.21 + return new Point(this.x, this.y);
1.22 + },
1.23 +
1.24 + set: function set(x, y) {
1.25 + this.x = x;
1.26 + this.y = y;
1.27 + return this;
1.28 + },
1.29 +
1.30 + equals: function equals(x, y) {
1.31 + return this.x == x && this.y == y;
1.32 + },
1.33 +
1.34 + toString: function toString() {
1.35 + return "(" + this.x + "," + this.y + ")";
1.36 + },
1.37 +
1.38 + map: function map(f) {
1.39 + this.x = f.call(this, this.x);
1.40 + this.y = f.call(this, this.y);
1.41 + return this;
1.42 + },
1.43 +
1.44 + add: function add(x, y) {
1.45 + this.x += x;
1.46 + this.y += y;
1.47 + return this;
1.48 + },
1.49 +
1.50 + subtract: function subtract(x, y) {
1.51 + this.x -= x;
1.52 + this.y -= y;
1.53 + return this;
1.54 + },
1.55 +
1.56 + scale: function scale(s) {
1.57 + this.x *= s;
1.58 + this.y *= s;
1.59 + return this;
1.60 + },
1.61 +
1.62 + isZero: function() {
1.63 + return this.x == 0 && this.y == 0;
1.64 + }
1.65 +};
1.66 +
1.67 +(function() {
1.68 + function takePointOrArgs(f) {
1.69 + return function(arg1, arg2) {
1.70 + if (arg2 === undefined)
1.71 + return f.call(this, arg1.x, arg1.y);
1.72 + else
1.73 + return f.call(this, arg1, arg2);
1.74 + };
1.75 + }
1.76 +
1.77 + for each (let f in ['add', 'subtract', 'equals', 'set'])
1.78 + Point.prototype[f] = takePointOrArgs(Point.prototype[f]);
1.79 +})();
1.80 +
1.81 +
1.82 +/**
1.83 + * Rect is a simple data structure for representation of a rectangle supporting
1.84 + * many basic geometric operations.
1.85 + *
1.86 + * NOTE: Since its operations are closed, rectangles may be empty and will report
1.87 + * non-positive widths and heights in that case.
1.88 + */
1.89 +
1.90 +this.Rect = function Rect(x, y, w, h) {
1.91 + this.left = x;
1.92 + this.top = y;
1.93 + this.right = x + w;
1.94 + this.bottom = y + h;
1.95 +};
1.96 +
1.97 +Rect.fromRect = function fromRect(r) {
1.98 + return new Rect(r.left, r.top, r.right - r.left, r.bottom - r.top);
1.99 +};
1.100 +
1.101 +Rect.prototype = {
1.102 + get x() { return this.left; },
1.103 + get y() { return this.top; },
1.104 + get width() { return this.right - this.left; },
1.105 + get height() { return this.bottom - this.top; },
1.106 + set x(v) {
1.107 + let diff = this.left - v;
1.108 + this.left = v;
1.109 + this.right -= diff;
1.110 + },
1.111 + set y(v) {
1.112 + let diff = this.top - v;
1.113 + this.top = v;
1.114 + this.bottom -= diff;
1.115 + },
1.116 + set width(v) { this.right = this.left + v; },
1.117 + set height(v) { this.bottom = this.top + v; },
1.118 +
1.119 + isEmpty: function isEmpty() {
1.120 + return this.left >= this.right || this.top >= this.bottom;
1.121 + },
1.122 +
1.123 + setRect: function(x, y, w, h) {
1.124 + this.left = x;
1.125 + this.top = y;
1.126 + this.right = x+w;
1.127 + this.bottom = y+h;
1.128 +
1.129 + return this;
1.130 + },
1.131 +
1.132 + setBounds: function(l, t, r, b) {
1.133 + this.top = t;
1.134 + this.left = l;
1.135 + this.bottom = b;
1.136 + this.right = r;
1.137 +
1.138 + return this;
1.139 + },
1.140 +
1.141 + equals: function equals(other) {
1.142 + return other != null &&
1.143 + (this.isEmpty() && other.isEmpty() ||
1.144 + this.top == other.top &&
1.145 + this.left == other.left &&
1.146 + this.bottom == other.bottom &&
1.147 + this.right == other.right);
1.148 + },
1.149 +
1.150 + clone: function clone() {
1.151 + return new Rect(this.left, this.top, this.right - this.left, this.bottom - this.top);
1.152 + },
1.153 +
1.154 + center: function center() {
1.155 + if (this.isEmpty())
1.156 + throw "Empty rectangles do not have centers";
1.157 + return new Point(this.left + (this.right - this.left) / 2,
1.158 + this.top + (this.bottom - this.top) / 2);
1.159 + },
1.160 +
1.161 + copyFrom: function(other) {
1.162 + this.top = other.top;
1.163 + this.left = other.left;
1.164 + this.bottom = other.bottom;
1.165 + this.right = other.right;
1.166 +
1.167 + return this;
1.168 + },
1.169 +
1.170 + translate: function(x, y) {
1.171 + this.left += x;
1.172 + this.right += x;
1.173 + this.top += y;
1.174 + this.bottom += y;
1.175 +
1.176 + return this;
1.177 + },
1.178 +
1.179 + toString: function() {
1.180 + return "[" + this.x + "," + this.y + "," + this.width + "," + this.height + "]";
1.181 + },
1.182 +
1.183 + /** return a new rect that is the union of that one and this one */
1.184 + union: function(other) {
1.185 + return this.clone().expandToContain(other);
1.186 + },
1.187 +
1.188 + contains: function(other) {
1.189 + if (other.isEmpty()) return true;
1.190 + if (this.isEmpty()) return false;
1.191 +
1.192 + return (other.left >= this.left &&
1.193 + other.right <= this.right &&
1.194 + other.top >= this.top &&
1.195 + other.bottom <= this.bottom);
1.196 + },
1.197 +
1.198 + intersect: function(other) {
1.199 + return this.clone().restrictTo(other);
1.200 + },
1.201 +
1.202 + intersects: function(other) {
1.203 + if (this.isEmpty() || other.isEmpty())
1.204 + return false;
1.205 +
1.206 + let x1 = Math.max(this.left, other.left);
1.207 + let x2 = Math.min(this.right, other.right);
1.208 + let y1 = Math.max(this.top, other.top);
1.209 + let y2 = Math.min(this.bottom, other.bottom);
1.210 + return x1 < x2 && y1 < y2;
1.211 + },
1.212 +
1.213 + /** Restrict area of this rectangle to the intersection of both rectangles. */
1.214 + restrictTo: function restrictTo(other) {
1.215 + if (this.isEmpty() || other.isEmpty())
1.216 + return this.setRect(0, 0, 0, 0);
1.217 +
1.218 + let x1 = Math.max(this.left, other.left);
1.219 + let x2 = Math.min(this.right, other.right);
1.220 + let y1 = Math.max(this.top, other.top);
1.221 + let y2 = Math.min(this.bottom, other.bottom);
1.222 + // If width or height is 0, the intersection was empty.
1.223 + return this.setRect(x1, y1, Math.max(0, x2 - x1), Math.max(0, y2 - y1));
1.224 + },
1.225 +
1.226 + /** Expand this rectangle to the union of both rectangles. */
1.227 + expandToContain: function expandToContain(other) {
1.228 + if (this.isEmpty()) return this.copyFrom(other);
1.229 + if (other.isEmpty()) return this;
1.230 +
1.231 + let l = Math.min(this.left, other.left);
1.232 + let r = Math.max(this.right, other.right);
1.233 + let t = Math.min(this.top, other.top);
1.234 + let b = Math.max(this.bottom, other.bottom);
1.235 + return this.setRect(l, t, r-l, b-t);
1.236 + },
1.237 +
1.238 + /**
1.239 + * Expands to the smallest rectangle that contains original rectangle and is bounded
1.240 + * by lines with integer coefficients.
1.241 + */
1.242 + expandToIntegers: function round() {
1.243 + this.left = Math.floor(this.left);
1.244 + this.top = Math.floor(this.top);
1.245 + this.right = Math.ceil(this.right);
1.246 + this.bottom = Math.ceil(this.bottom);
1.247 + return this;
1.248 + },
1.249 +
1.250 + scale: function scale(xscl, yscl) {
1.251 + this.left *= xscl;
1.252 + this.right *= xscl;
1.253 + this.top *= yscl;
1.254 + this.bottom *= yscl;
1.255 + return this;
1.256 + },
1.257 +
1.258 + map: function map(f) {
1.259 + this.left = f.call(this, this.left);
1.260 + this.top = f.call(this, this.top);
1.261 + this.right = f.call(this, this.right);
1.262 + this.bottom = f.call(this, this.bottom);
1.263 + return this;
1.264 + },
1.265 +
1.266 + /** Ensure this rectangle is inside the other, if possible. Preserves w, h. */
1.267 + translateInside: function translateInside(other) {
1.268 + let offsetX = (this.left <= other.left ? other.left - this.left :
1.269 + (this.right > other.right ? other.right - this.right : 0));
1.270 + let offsetY = (this.top <= other.top ? other.top - this.top :
1.271 + (this.bottom > other.bottom ? other.bottom - this.bottom : 0));
1.272 + return this.translate(offsetX, offsetY);
1.273 + },
1.274 +
1.275 + /** Subtract other area from this. Returns array of rects whose union is this-other. */
1.276 + subtract: function subtract(other) {
1.277 + let r = new Rect(0, 0, 0, 0);
1.278 + let result = [];
1.279 + other = other.intersect(this);
1.280 + if (other.isEmpty())
1.281 + return [this.clone()];
1.282 +
1.283 + // left strip
1.284 + r.setBounds(this.left, this.top, other.left, this.bottom);
1.285 + if (!r.isEmpty())
1.286 + result.push(r.clone());
1.287 + // inside strip
1.288 + r.setBounds(other.left, this.top, other.right, other.top);
1.289 + if (!r.isEmpty())
1.290 + result.push(r.clone());
1.291 + r.setBounds(other.left, other.bottom, other.right, this.bottom);
1.292 + if (!r.isEmpty())
1.293 + result.push(r.clone());
1.294 + // right strip
1.295 + r.setBounds(other.right, this.top, this.right, this.bottom);
1.296 + if (!r.isEmpty())
1.297 + result.push(r.clone());
1.298 +
1.299 + return result;
1.300 + },
1.301 +
1.302 + /**
1.303 + * Blends two rectangles together.
1.304 + * @param rect Rectangle to blend this one with
1.305 + * @param scalar Ratio from 0 (returns a clone of this rect) to 1 (clone of rect).
1.306 + * @return New blended rectangle.
1.307 + */
1.308 + blend: function blend(rect, scalar) {
1.309 + return new Rect(
1.310 + this.left + (rect.left - this.left ) * scalar,
1.311 + this.top + (rect.top - this.top ) * scalar,
1.312 + this.width + (rect.width - this.width ) * scalar,
1.313 + this.height + (rect.height - this.height) * scalar);
1.314 + },
1.315 +
1.316 + /**
1.317 + * Grows or shrinks the rectangle while keeping the center point.
1.318 + * Accepts single multipler, or separate for both axes.
1.319 + */
1.320 + inflate: function inflate(xscl, yscl) {
1.321 + let xAdj = (this.width * xscl - this.width) / 2;
1.322 + let s = (arguments.length > 1) ? yscl : xscl;
1.323 + let yAdj = (this.height * s - this.height) / 2;
1.324 + this.left -= xAdj;
1.325 + this.right += xAdj;
1.326 + this.top -= yAdj;
1.327 + this.bottom += yAdj;
1.328 + return this;
1.329 + }
1.330 +};
