[css] CSS filter: make color image with transparency white

I have a colored png image with transparency. I would like to use css filter to make the whole image white but leave the transparency as it is. Is that possible in CSS?

This question is related to css css-filters

The answer is


To my knowledge, there is sadly no CSS filter to colorise an element (perhaps with the use of some SVG filter magic, but I'm somewhat unfamiliar with that) and even if that wasn't the case, filters are basically only supported by webkit browsers.

With that said, you could still work around this and use a canvas to modify your image. Basically, you can draw an image element onto a canvas and then loop through the pixels, modifying the respective RGBA values to the colour you want.

However, canvases do come with some restrictions. Most importantly, you have to make sure that the image src comes from the same domain as the page. Otherwise the browser won't allow you to read or modify the pixel data of the canvas.

Here's a JSFiddle changing the colour of the JSFiddle logo.

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//Base64 source, but any local source will work_x000D_
var src = "data:image/png;base64,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";_x000D_
var canvas = document.getElementById("theCanvas");_x000D_
var ctx = canvas.getContext("2d");_x000D_
var img = new Image;_x000D_
_x000D_
//wait for the image to load_x000D_
img.onload = function() {_x000D_
    //Draw the original image so that you can fetch the colour data_x000D_
    ctx.drawImage(img,0,0);_x000D_
    var imgData = ctx.getImageData(0, 0, canvas.width, canvas.height);_x000D_
    _x000D_
    /*_x000D_
    imgData.data is a one-dimensional array which contains _x000D_
    the respective RGBA values for every pixel _x000D_
    in the selected region of the context _x000D_
    (note i+=4 in the loop)_x000D_
    */_x000D_
    _x000D_
    for (var i = 0; i < imgData.data.length; i+=4) {_x000D_
   imgData.data[i] = 255; //Red, 0-255_x000D_
   imgData.data[i+1] = 255; //Green, 0-255_x000D_
   imgData.data[i+2] = 255; //Blue, 0-255_x000D_
   /* _x000D_
   imgData.data[i+3] contains the alpha value_x000D_
   which we are going to ignore and leave_x000D_
   alone with its original value_x000D_
   */_x000D_
    }_x000D_
    ctx.clearRect(0, 0, canvas.width, canvas.height); //clear the original image_x000D_
    ctx.putImageData(imgData, 0, 0); //paint the new colorised image_x000D_
}_x000D_
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//Load the image!_x000D_
img.src = src;
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body {_x000D_
    background: green;_x000D_
}
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<canvas id="theCanvas"></canvas>
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