Book Image

Canvas Cookbook

Book Image

Canvas Cookbook

Overview of this book

With the growing popularity of HTML5 Canvas, this book offers tailored recipes to help you develop portable applications, presentations, and games. The recipes are simple yet creative and build on each other. At every step, the book inspires the reader to develop his/her own recipe. From basic to advanced, every aspect of Canvas API has been covered to guide readers to develop their own application, presentation, or game.
Table of Contents (16 chapters)
Canvas Cookbook
About the Author
About the Reviewer

Rendering effects to images

This recipe shows the various effects that can be applied to an image. The output of the recipe is as shown here:

How to do it

The recipe is as follows:

The HTML code:

<script src="ImageEffects.js"></script>
<body onload="init();">
<canvas id="MyCanvasArea" width="650" height="450" style="border:2px solid blue;" >
your browser does not support canvas</canvas>
<h1>Image Effects-normal,negative,gryascale,red,sepia& noise</h1>

The JavaScript code:

var can;var ctx;var boyimage;var x,y;var imageData;var imgPixels;

var red;var green;var blue;var alpha;var avg;

function init(){
  can = document.getElementById('MyCanvasArea'),
  ctx = can.getContext('2d');
  var imageObj=new Image();