graphics/circle.js

  1. 'use strict';
  3. var Thing = require('./thing.js');
  4. var Color = require('./color.js');
  5. var graphicsUtils = require('./graphics-utils.js');
  7. /**
  8.  * @class Circle
  9.  * @augments Thing
  10.  * @param {number} radius - Desired radius
  11.  */
  12. function Circle(radius) {
  13.     if (arguments.length !== 1) {
  14.         throw new Error('You should pass exactly 1 argument to <span ' +
  15.             'class="code">new Circle(radius)</span>');
  16.     }
  17.     if (typeof radius !== 'number' || !isFinite(radius)) {
  18.         throw new TypeError('You must pass a finite number to <span class=' +
  19.             '"code">new Circle(radius)</span>. Did you forget the ' +
  20.             'parentheses in <span class="code">getWidth()</span> or <span ' +
  21.             'class="code">getHeight()</span>? Or did you perform a ' +
  22.             'calculation on a variable that is not a number?');
  23.     }
  25.     Thing.call(this);
  26.     this.radius = Math.max(0, radius);
  27.     this.color = Color.black;
  28.     this.lineWidth = 3;
  29.     this.type = 'Circle';
  30. }
  32. Circle.prototype = new Thing();
  33. Circle.prototype.constructor = Circle;
  35. /**
  36.  * Draws the circle in the canvas.
  37.  * @param {CodeHSGraphics} __graphics__ - Instance of the Graphics module.
  38.  */
  39. Circle.prototype.draw = function(__graphics__) {
  40.     var context = __graphics__.getContext();
  41.     context.beginPath();
  43.     if (this.hasBorder) {
  44.         context.strokeStyle = this.stroke.toString();
  45.         context.lineWidth = this.lineWidth;
  46.     }
  47.     context.fillStyle = this.color.toString();
  48.     context.arc(this.x,this.y,this.radius,0,Math.PI * 2,true);
  49.     context.closePath();
  51.     if (this.hasBorder) {
  52.         context.stroke();
  53.     }
  54.     context.fill();
  55. };
  57. /**
  58.  * Gets the radius of the circle
  59.  * @returns {number} Radius of the circle.
  60.  */
  61. Circle.prototype.getRadius = function() {
  62.     return this.radius;
  63. };
  65. /**
  66.  * Gets the height (diamter) of the circle.
  67.  * @returns {number} Height (diameter) of the circle.
  68.  */
  69. Circle.prototype.getHeight = function() {
  70.     return this.radius * 2;
  71. };
  73. /**
  74.  * Gets the width (diamter) of the circle.
  75.  * @returns {number} Width (diameter) of the circle.
  76.  */
  77. Circle.prototype.getWidth = function() {
  78.     return this.radius * 2;
  79. };
  81. /**
  82.  * Sets the radius of the circle.
  83.  * @param {number} radius - Desired resulting radius of the circle.
  84.  */
  85. Circle.prototype.setRadius = function(radius) {
  86.     if (arguments.length !== 1) {
  87.         throw new Error('You should pass exactly 1 argument to <span ' +
  88.             'class="code">setRadius(radius)</span>');
  89.     }
  90.     if (typeof radius !== 'number' || !isFinite(radius)) {
  91.         throw new TypeError('You must pass a finite number to <span class=' +
  92.             '"code">setRadius(radius)</span>. Did you forget the ' +
  93.             'parentheses in <span class="code">getWidth()</span> or <span ' +
  94.             'class="code">getHeight()</span>? Or did you perform a ' +
  95.             'calculation on a variable that is not a number?');
  96.     }
  98.     this.radius = Math.max(0, radius);
  99. };
  101. /**
  102.  * Checks if the passed point is contained in the circle.
  103.  * @param {number} x - The x coordinate of the point being tested.
  104.  * @param {number} y - The y coordinate of the point being tested.
  105.  * @returns {boolean} Whether the passed point is contained in the circle.
  106.  */
  107. Circle.prototype.containsPoint = function(x, y) {
  108.     var circleEdge = this.radius;
  109.     if (this.hasBorder) {
  110.         circleEdge += this.lineWidth;
  111.     }
  112.     var dist = graphicsUtils.getDistance(this.x, this.y, x, y);
  113.     return dist < circleEdge;
  114. };
  116. module.exports = Circle;