HTML Canvas Image change pixel value

Description

HTML Canvas Image change pixel value

View in separate window 

<!DOCTYPE html>

<html>
  <head>
    <title>Manipulating images and video</title>
    <meta charset="utf-8">
    //from  w ww. j av  a 2  s.com
    <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");
        
        // Drawing pixels to the canvas
        var imageData = context.createImageData(200, 200);
        var pixels = imageData.data;
        var numPixels = imageData.width*imageData.height;
        
        // Access and change pixel values
        for (var i = 0; i < numPixels; i++) {
          pixels[i*4] = 255; // Red
          pixels[i*4+1] = 0; // Green
          pixels[i*4+2] = 0; // Blue
          pixels[i*4+3] = 255; // Alpha
        };
        
        // Draw image data to the canvas
        context.putImageData(imageData, 0, 0);
        

      });
    </script>
  </head>
  
  <body>
    <canvas id="myCanvas" width="500" height="500">
      <!-- Insert fallback content here -->
    </canvas>
  </body>
</html>



PreviousNext

Related