Skip to main content

How to create a waveform animation with HTML and JavaScript

Recently, for a pet project, I wanted to create an animation of a waveform based on the varying decibel level of the microphone input. I was thinking about a really simple way to accomplish this with SVG and JavaScript. Given below is the first sample code I did on the Codepen. You can change this code to use with any framework of your choice.

For this sample code, I am using a random number as the microphone input. You can replace it with any other time based input.

Code Pen : https://codepen.io/nadeeth/pen/vmaYXw

For this example, you need an HTML code snippet like the one given below. It’s just an SVG with a Polyline element inside. 

<div style="text-align:center">
  <svg height="150" width="400" id='svg'>
    <polyline id="polyline-id" fill="none" stroke="#005c66" stroke-width="1" />
  </svg>
</div>
And then the plain Javascript code to animate the polyline. You can replace the setInterval function and the statement that generates the random number based on your actual need.

var svg = document.getElementById('svg');
var polyline= document.getElementById('polyline-id');
var width = 400;
var height = 150;
var x = 0;

setInterval(function(){ 
  //Create the new point and increment the x for the next point
  var point = svg.createSVGPoint();
  point.x = x;
  point.y = height - Math.floor((Math.random() * height));
  polyline.points.appendItem(point);
  x++;

  //Reset the x axis points when the line reaches the width
  if (polyline.points.length > width) { 
    //Remove the first point to make space for the last point
    polyline.points.removeItem(0);
    //Reset x points
    for (var j=0; j<width; j++) { 
      polyline.points[j].x = j;
    }
  }
}, 100);

Comments

Popular posts from this blog

Common Characteristics of Enterprise Applications

Last week, I was conducting a tech talk about “Architectural Patterns of Enterprise Applications” with our team. The discussion was mainly based on Marin Fowler's famous book “Patterns of Enterprise Application Architecture”. So, I thought, it's good to write something about that in my Blog. Given below are few common characteristics of Enterprise Applications. If any software product has the following characteristics, we can identify it as an Enterprise Application. These ware originally documented by “Martin Fowler”, in his book “Patterns of Enterprise Application Architecture”. Persistent Data - Enterprise applications usually involve persistent data. The data is persistent because it needs to be around between multiple runs of the program—indeed, it usually needs to persist for several years. Also during this time there will be many changes in the programs that use it. Lot of Data - There's usually a lot of data, a moderate system will have over 1 GB of data organ

How to create a new module for vtiger...

Recently, I had to create a new module for vtigerCRM for my client in current working place. I did search in many places including the official vtiger sites, but couldn’t find a better documentation for my purpose. The latest vtiger version at that time was 5.0.3. Because I had some experience doing lots of core modifications for this system, I did decide to read the source code and find how to add a new module. Finally, I could create a new module and started the project. So, I thought it will be a good thing to write some thing on my blog about this topic, so that others who want to do this thing can read. Given below is a brief description about how to create a new module for vtiger CRM 5.0.3. Source code of this example module is also available to Download . Step 01: Creating the module directory and minimum required files. Create a directory called “newModule” inside your vtiger modules directory, or any other name that you prefer. Now, module index file should be created. Creat

How to avoid those little issues one can get when creating new projects with Zend Framwork...

CSS styles my not apply to the templates : Some times this happens when you haven't created a virtual host for the application. After the virtual host is created styles will apply properly, or just use some url helper like "baseUrl" when linking the style sheets to the templates. Error messages when using the commands like "zf enable layout", "zf create db-table ....", "zf create model ...", "zf configure db-adapter", and "zf create action ...." etc... You may get error like "Action 'enable' is not a valid action", "Action 'configure' is not a valid action"......... etc... Reason for this may be, the Zend library is not in the include path. If so add the library path to the include path. Or check whether there are old libraries in any directories of include paths that conflicts with the new one. Check whether there is a one as a PEAR package. And check whether the "zf" c