How to save an image with CSS filter applied

Question

I am wondering how I can apply a CSS filter to an image and then save the image to disk.

For example, I have an image tag, I can apply a sepia effect via CSS

img.sepia{
  filter: sepia(20%);
}

And apply the class to an image tag in the HTML

<img src="img.png" class="sepia" />

How can I save that image with the filter applied?

Answer 1

You could write the image to a canvas element, set the filter you want in javascript and then download that. So it would be something like this

var canvas = document.getElementById('image');
var ctx = canvas.getContext('2d');
ctx.filter = "sepia(20%)";
var img = document.getElementById("dataimage");
ctx.drawImage(img,0,0, canvas.width, canvas.height);

var downloadFile = document.getElementById('download');
downloadFile.addEventListener('click', download, false);


function download() {
   var dt = canvas.toDataURL('image/jpeg');
   this.href = dt;
};

img{
  width:400px;
  height:400px;
}

<img src="" id="dataimage" />
<canvas id="image" width="400px" height="400px"></canvas>
<a id="download">Download image</a>