A collection of useful canvas methods

basic-canvas.js

var BasicCanvas = (function() {
  
  return {
    
    init: function() {
      this.canvas = document.getElementById('canvas');
      this.ctx = this.canvas.getContext('2d');
      this.setSize(window.innerWidth, window.innerHeight);
    },
    
    setSize: function(x, y) {
      this.width = this.canvas.width = x;
      this.height = this.canvas.height = y;
    },
    
    clear: function(color) {
      if(color) {
        this.ctx.fillStyle = color;
        this.ctx.fillRect(0, 0, this.width, this.height);
      } else {
        this.clearRect(0, 0, this.width, this.height); 
      }
    },
    
    getImage: function() {
      var newWindow = window.open('', "Image"),
          src = this.canvas.toDataURL("image/png");     
      newWindow.document.write('<img src="'+ src +'" />');   
    },
    
    degToRad: function(degrees) {
      return degrees * (Math.PI/180);
    },
    
    radToDeg: function(radians) {
      return radians * (180/Math.PI);
    },
    
    randomiseNum: function(num, tolerance) {
      var toleranceRange;
      if(num > 0) {
          toleranceRange = (tolerance * num) / 100;
      } else {
          return 0;
      }
      return (num + toleranceRange) + ((toleranceRange * 2) * Math.random()); 
    }
  }
  
})();