HTML5 - Canvas

HTML5 element <canvas> gives you an easy and powerful way to draw graphics using JavaScript. It can be used to draw graphs, make photo compositions or do simple (and not so simple) animations.
Here is a simple <canvas> element which has only two specific attributeswidth and height plus all the core HTML5 attributes like id, name and class etc.
<canvas id="mycanvas" width="100" height="100"></canvas>
You can easily find that <canvas> element in the DOM using getElementById()method as follows −
var canvas  = document.getElementById("mycanvas");
Let us see a simple example on using <canvas> element in HTML5 document.
<!DOCTYPE HTML>
<html>
   <head>
   
      <style>
         #mycanvas{border:1px solid red;}
      </style>
      
   </head>
   <body>

      <canvas id="mycanvas" width="100" height="100"></canvas>
      
   </body>
</html>
This will produce following result −

The Rendering Context

The <canvas> is initially blank, and to display something, a script first needs to access the rendering context and draw on it.
The canvas element has a DOM method called getContext, used to obtain the rendering context and its drawing functions. This function takes one parameter, the type of context 2d.
Following is the code to get required context along with a check if your browser supports <canvas> element −
var canvas  = document.getElementById("mycanvas");

if (canvas.getContext){   
   var ctx = canvas.getContext('2d');   
   // drawing code here   
} 

else {   
   // canvas-unsupported code here 
}

Browser Support

The latest versions of Firefox, Safari, Chrome and Opera all support for HTML5 Canvas but IE8 does not support canvas natively.
You can use ExplorerCanvas to have canvas support through Internet Explorer. You just need to include this javascript as follows:
<!--[if IE]><script src="excanvas.js"></script><![endif]-->

HTML5 Canvas Examples

This tutorial covers following examples related to HTML5 <canvas> element.
ExamplesDescription
Learn how to draw rectangle using HTML5 <canvas> element
Learn how to make shapes using paths in HTML5 <canvas> element
Learn how to draw lines using HTML5 <canvas> element
Learn how to draw bezier curve using HTML5 <canvas> element
Learn how to draw quadratic curve using HTML5 <canvas> element
Learn how to use images with HTML5 <canvas> element
Learn how to create gradients using HTML5 <canvas> element
Learn how to apply styles and colors using HTML5 <canvas> element
Learn how to draw amazing text using different fonts and their size.
Learn how to draw different patterns and drop shadows.
Learn how to save and restore canvas states while doing complex drawings on a canvas.
This method is used to move the canvas and its origin to a different point in the grid.
This method is used to rotate the canvas around the current origin.
This method is used to increase or decrease the units in a canvas grid.
These methods allow modifications directly to the transformation matrix.
This method is used to mask off certain areas or clear sections from the canvas.
Learn how to create basic animation using HTML5 canvas and Javascript.
Labels: ,

No comments:

Post a Comment

Subscribe to: Post Comments (Atom)