Canvas How to - Scale and flip an image

Question

We would like to know how to scale and flip an image.
Answer


<!--from ww  w  .  j  a v  a  2s  .  c  om-->
<!DOCTYPE html>
<html>
  <head>
    <title>Manipulating images and video</title>
    <meta charset="utf-8">
    
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
    
    <script type="text/javascript">
      $(document).ready(function() {  
        var canvas = $("#myCanvas");
        var context = canvas.get(0).getContext("2d");
        
        // Scaling and flipping
        var image = new Image();
        image.src = "http://www.java2s.com/style/download.png";
        $(image).load(function() {
          // Top left
          context.translate(50, 50);
          context.drawImage(image, 0, 0, 500, 500, 0, 0, 200, 200);
          
          // Bottom left
          context.setTransform(1, 0, 0, 1, 0, 0); // Reset the transformation matrix
          context.translate(50, 450);
          context.scale(1, -1);
          
          context.drawImage(image, 0, 0, 500, 500, 0, 0, 200, 200);
        
          // Bottom right
          context.setTransform(1, 0, 0, 1, 0, 0);
          context.translate(450, 450);
          context.scale(-1, -1);
          
          context.drawImage(image, 0, 0, 500, 500, 0, 0, 200, 200);
          
          // Top right
          context.setTransform(1, 0, 0, 1, 0, 0);
          context.translate(450, 50);
          context.scale(-1, 1);
          
          context.drawImage(image, 0, 0, 500, 500, 0, 0, 200, 200);
        });
        
      });
    </script>
  </head>
  
  <body>
    <canvas id="myCanvas" width="500" height="500">
      <!-- Insert fallback content here -->
    </canvas>
  </body>
</html>
The code above is rendered as follows: