michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = ["Point", "Rect"];
michael@0: 
michael@0: /**
michael@0:  * Simple Point class.
michael@0:  *
michael@0:  * Any method that takes an x and y may also take a point.
michael@0:  */
michael@0: this.Point = function Point(x, y) {
michael@0:   this.set(x, y);
michael@0: }
michael@0: 
michael@0: Point.prototype = {
michael@0:   clone: function clone() {
michael@0:     return new Point(this.x, this.y);
michael@0:   },
michael@0: 
michael@0:   set: function set(x, y) {
michael@0:     this.x = x;
michael@0:     this.y = y;
michael@0:     return this;
michael@0:   },
michael@0: 
michael@0:   equals: function equals(x, y) {
michael@0:     return this.x == x && this.y == y;
michael@0:   },
michael@0: 
michael@0:   toString: function toString() {
michael@0:     return "(" + this.x + "," + this.y + ")";
michael@0:   },
michael@0: 
michael@0:   map: function map(f) {
michael@0:     this.x = f.call(this, this.x);
michael@0:     this.y = f.call(this, this.y);
michael@0:     return this;
michael@0:   },
michael@0: 
michael@0:   add: function add(x, y) {
michael@0:     this.x += x;
michael@0:     this.y += y;
michael@0:     return this;
michael@0:   },
michael@0: 
michael@0:   subtract: function subtract(x, y) {
michael@0:     this.x -= x;
michael@0:     this.y -= y;
michael@0:     return this;
michael@0:   },
michael@0: 
michael@0:   scale: function scale(s) {
michael@0:     this.x *= s;
michael@0:     this.y *= s;
michael@0:     return this;
michael@0:   },
michael@0: 
michael@0:   isZero: function() {
michael@0:     return this.x == 0 && this.y == 0;
michael@0:   }
michael@0: };
michael@0: 
michael@0: (function() {
michael@0:   function takePointOrArgs(f) {
michael@0:     return function(arg1, arg2) {
michael@0:       if (arg2 === undefined)
michael@0:         return f.call(this, arg1.x, arg1.y);
michael@0:       else
michael@0:         return f.call(this, arg1, arg2);
michael@0:     };
michael@0:   }
michael@0: 
michael@0:   for each (let f in ['add', 'subtract', 'equals', 'set'])
michael@0:     Point.prototype[f] = takePointOrArgs(Point.prototype[f]);
michael@0: })();
michael@0: 
michael@0: 
michael@0: /**
michael@0:  * Rect is a simple data structure for representation of a rectangle supporting
michael@0:  * many basic geometric operations.
michael@0:  *
michael@0:  * NOTE: Since its operations are closed, rectangles may be empty and will report
michael@0:  * non-positive widths and heights in that case.
michael@0:  */
michael@0: 
michael@0: this.Rect = function Rect(x, y, w, h) {
michael@0:   this.left = x;
michael@0:   this.top = y;
michael@0:   this.right = x + w;
michael@0:   this.bottom = y + h;
michael@0: };
michael@0: 
michael@0: Rect.fromRect = function fromRect(r) {
michael@0:   return new Rect(r.left, r.top, r.right - r.left, r.bottom - r.top);
michael@0: };
michael@0: 
michael@0: Rect.prototype = {
michael@0:   get x() { return this.left; },
michael@0:   get y() { return this.top; },
michael@0:   get width() { return this.right - this.left; },
michael@0:   get height() { return this.bottom - this.top; },
michael@0:   set x(v) {
michael@0:     let diff = this.left - v;
michael@0:     this.left = v;
michael@0:     this.right -= diff;
michael@0:   },
michael@0:   set y(v) {
michael@0:     let diff = this.top - v;
michael@0:     this.top = v;
michael@0:     this.bottom -= diff;
michael@0:   },
michael@0:   set width(v) { this.right = this.left + v; },
michael@0:   set height(v) { this.bottom = this.top + v; },
michael@0: 
michael@0:   isEmpty: function isEmpty() {
michael@0:     return this.left >= this.right || this.top >= this.bottom;
michael@0:   },
michael@0: 
michael@0:   setRect: function(x, y, w, h) {
michael@0:     this.left = x;
michael@0:     this.top = y;
michael@0:     this.right = x+w;
michael@0:     this.bottom = y+h;
michael@0: 
michael@0:     return this;
michael@0:   },
michael@0: 
michael@0:   setBounds: function(l, t, r, b) {
michael@0:     this.top = t;
michael@0:     this.left = l;
michael@0:     this.bottom = b;
michael@0:     this.right = r;
michael@0: 
michael@0:     return this;
michael@0:   },
michael@0: 
michael@0:   equals: function equals(other) {
michael@0:     return other != null &&
michael@0:             (this.isEmpty() && other.isEmpty() ||
michael@0:             this.top == other.top &&
michael@0:             this.left == other.left &&
michael@0:             this.bottom == other.bottom &&
michael@0:             this.right == other.right);
michael@0:   },
michael@0: 
michael@0:   clone: function clone() {
michael@0:     return new Rect(this.left, this.top, this.right - this.left, this.bottom - this.top);
michael@0:   },
michael@0: 
michael@0:   center: function center() {
michael@0:     if (this.isEmpty())
michael@0:       throw "Empty rectangles do not have centers";
michael@0:     return new Point(this.left + (this.right - this.left) / 2,
michael@0:                           this.top + (this.bottom - this.top) / 2);
michael@0:   },
michael@0: 
michael@0:   copyFrom: function(other) {
michael@0:     this.top = other.top;
michael@0:     this.left = other.left;
michael@0:     this.bottom = other.bottom;
michael@0:     this.right = other.right;
michael@0: 
michael@0:     return this;
michael@0:   },
michael@0: 
michael@0:   translate: function(x, y) {
michael@0:     this.left += x;
michael@0:     this.right += x;
michael@0:     this.top += y;
michael@0:     this.bottom += y;
michael@0: 
michael@0:     return this;
michael@0:   },
michael@0: 
michael@0:   toString: function() {
michael@0:     return "[" + this.x + "," + this.y + "," + this.width + "," + this.height + "]";
michael@0:   },
michael@0: 
michael@0:   /** return a new rect that is the union of that one and this one */
michael@0:   union: function(other) {
michael@0:     return this.clone().expandToContain(other);
michael@0:   },
michael@0: 
michael@0:   contains: function(other) {
michael@0:     if (other.isEmpty()) return true;
michael@0:     if (this.isEmpty()) return false;
michael@0: 
michael@0:     return (other.left >= this.left &&
michael@0:             other.right <= this.right &&
michael@0:             other.top >= this.top &&
michael@0:             other.bottom <= this.bottom);
michael@0:   },
michael@0: 
michael@0:   intersect: function(other) {
michael@0:     return this.clone().restrictTo(other);
michael@0:   },
michael@0: 
michael@0:   intersects: function(other) {
michael@0:     if (this.isEmpty() || other.isEmpty())
michael@0:       return false;
michael@0: 
michael@0:     let x1 = Math.max(this.left, other.left);
michael@0:     let x2 = Math.min(this.right, other.right);
michael@0:     let y1 = Math.max(this.top, other.top);
michael@0:     let y2 = Math.min(this.bottom, other.bottom);
michael@0:     return x1 < x2 && y1 < y2;
michael@0:   },
michael@0: 
michael@0:   /** Restrict area of this rectangle to the intersection of both rectangles. */
michael@0:   restrictTo: function restrictTo(other) {
michael@0:     if (this.isEmpty() || other.isEmpty())
michael@0:       return this.setRect(0, 0, 0, 0);
michael@0: 
michael@0:     let x1 = Math.max(this.left, other.left);
michael@0:     let x2 = Math.min(this.right, other.right);
michael@0:     let y1 = Math.max(this.top, other.top);
michael@0:     let y2 = Math.min(this.bottom, other.bottom);
michael@0:     // If width or height is 0, the intersection was empty.
michael@0:     return this.setRect(x1, y1, Math.max(0, x2 - x1), Math.max(0, y2 - y1));
michael@0:   },
michael@0: 
michael@0:   /** Expand this rectangle to the union of both rectangles. */
michael@0:   expandToContain: function expandToContain(other) {
michael@0:     if (this.isEmpty()) return this.copyFrom(other);
michael@0:     if (other.isEmpty()) return this;
michael@0: 
michael@0:     let l = Math.min(this.left, other.left);
michael@0:     let r = Math.max(this.right, other.right);
michael@0:     let t = Math.min(this.top, other.top);
michael@0:     let b = Math.max(this.bottom, other.bottom);
michael@0:     return this.setRect(l, t, r-l, b-t);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Expands to the smallest rectangle that contains original rectangle and is bounded
michael@0:    * by lines with integer coefficients.
michael@0:    */
michael@0:   expandToIntegers: function round() {
michael@0:     this.left = Math.floor(this.left);
michael@0:     this.top = Math.floor(this.top);
michael@0:     this.right = Math.ceil(this.right);
michael@0:     this.bottom = Math.ceil(this.bottom);
michael@0:     return this;
michael@0:   },
michael@0: 
michael@0:   scale: function scale(xscl, yscl) {
michael@0:     this.left *= xscl;
michael@0:     this.right *= xscl;
michael@0:     this.top *= yscl;
michael@0:     this.bottom *= yscl;
michael@0:     return this;
michael@0:   },
michael@0: 
michael@0:   map: function map(f) {
michael@0:     this.left = f.call(this, this.left);
michael@0:     this.top = f.call(this, this.top);
michael@0:     this.right = f.call(this, this.right);
michael@0:     this.bottom = f.call(this, this.bottom);
michael@0:     return this;
michael@0:   },
michael@0: 
michael@0:   /** Ensure this rectangle is inside the other, if possible. Preserves w, h. */
michael@0:   translateInside: function translateInside(other) {
michael@0:     let offsetX = (this.left <= other.left ? other.left - this.left :
michael@0:                   (this.right > other.right ? other.right - this.right : 0));
michael@0:     let offsetY = (this.top <= other.top ? other.top - this.top :
michael@0:                   (this.bottom > other.bottom ? other.bottom - this.bottom : 0));
michael@0:     return this.translate(offsetX, offsetY);
michael@0:   },
michael@0: 
michael@0:   /** Subtract other area from this. Returns array of rects whose union is this-other. */
michael@0:   subtract: function subtract(other) {
michael@0:     let r = new Rect(0, 0, 0, 0);
michael@0:     let result = [];
michael@0:     other = other.intersect(this);
michael@0:     if (other.isEmpty())
michael@0:       return [this.clone()];
michael@0: 
michael@0:     // left strip
michael@0:     r.setBounds(this.left, this.top, other.left, this.bottom);
michael@0:     if (!r.isEmpty())
michael@0:       result.push(r.clone());
michael@0:     // inside strip
michael@0:     r.setBounds(other.left, this.top, other.right, other.top);
michael@0:     if (!r.isEmpty())
michael@0:       result.push(r.clone());
michael@0:     r.setBounds(other.left, other.bottom, other.right, this.bottom);
michael@0:     if (!r.isEmpty())
michael@0:       result.push(r.clone());
michael@0:     // right strip
michael@0:     r.setBounds(other.right, this.top, this.right, this.bottom);
michael@0:     if (!r.isEmpty())
michael@0:       result.push(r.clone());
michael@0: 
michael@0:     return result;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Blends two rectangles together.
michael@0:    * @param rect Rectangle to blend this one with
michael@0:    * @param scalar Ratio from 0 (returns a clone of this rect) to 1 (clone of rect).
michael@0:    * @return New blended rectangle.
michael@0:    */
michael@0:   blend: function blend(rect, scalar) {
michael@0:     return new Rect(
michael@0:       this.left   + (rect.left   - this.left  ) * scalar,
michael@0:       this.top    + (rect.top    - this.top   ) * scalar,
michael@0:       this.width  + (rect.width  - this.width ) * scalar,
michael@0:       this.height + (rect.height - this.height) * scalar);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Grows or shrinks the rectangle while keeping the center point.
michael@0:    * Accepts single multipler, or separate for both axes.
michael@0:    */
michael@0:   inflate: function inflate(xscl, yscl) {
michael@0:     let xAdj = (this.width * xscl - this.width) / 2;
michael@0:     let s = (arguments.length > 1) ? yscl : xscl;
michael@0:     let yAdj = (this.height * s - this.height) / 2;
michael@0:     this.left -= xAdj;
michael@0:     this.right += xAdj;
michael@0:     this.top -= yAdj;
michael@0:     this.bottom += yAdj;
michael@0:     return this;
michael@0:   }
michael@0: };