Blend mode:multiply in Internet Explorer

Question

I need to have an Image blended together with an red square in mode multiply. As I know, IE and Safari doesn't support the css-property "blend-mode", so I tried it with blending them together in a canvas and everything worked fine - except in IE. Is there any way to get those blended together in IE or isn't that supported yet?

Solution 1

For Internet Explorer, Canvas blending modes are "under consideration".

https://developer.microsoft.com/en-us/microsoft-edge/platform/status/mixblendmode/?q=blend

Until blends are implemented in IE, you can roll-your-own multiply filter:

function multiply(R, G, B) {
  var imgData = ctx.getImageData(0, 0, canvas.width, canvas.height);
  var data = imgData.data;

  for (var i = 0; i < data.length; i += 4) {
    data[i    ] = R * data[i    ] / 255;
    data[i + 1] = G * data[i + 1] / 255;
    data[i + 2] = B * data[i + 2] / 255;
  }

  ctx.putImageData(imgData, 0, 0);
}

And this multiply image filter is cross-browser compatible too.

Solution 2

Here I found a fully css solution:

https://teamtreehouse.com/community/fallback-for-css-blending-modes

which is:

<!--[if IE]>
  <style>
          .yourTargetClass:before {
               content: "";
               position: absolute;
               height: 100%;
               width: 100%;
               background: rgba(10, 36, 54, 0.9); /* THIS IS WHAT EVER OVERLAY COLOUR YOU WANT */
           }
   </style>

Comments

[Rudi Ørnhøj]

Not useful, opacity is not the same as multiply

[leymannx]

@RudiØrnhøj – You are right. It's not the same. It's a fallback. And it's pure CSS. Upvote incoming.

[Olivier Royo]

true but the target was to put a red border to the image, I think that makes the work.

[Joseph Marikle]

I found this answer very useful. To add to this, you can also mimic opacity of a multiplied layer. I found this one to be identical to Photoshop's multiply layer with opacity: (255 - 255 * opacity + R * opacity) * data[i] / 255 where opacity is a value between 0 and 1 (e.g. 0.75 would be a 75% opaque multiply layer). obviously this needs to be applied to all three color channels.