CSS CSS过滤器：制作透明白色的彩色图像
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CSS filter: make color image with transparency white
提问by Pascal Klein
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?
我有一个透明的彩色 png 图像。我想使用 css 过滤器使整个图像变白，但保持透明度不变。这在 CSS 中可能吗？
回答by Oriol
You can use
您可以使用
filter: brightness(0) invert(1);
html {
background: red;
}
p {
float: left;
max-width: 50%;
text-align: center;
}
img {
display: block;
max-width: 100%;
}
.filter {
-webkit-filter: brightness(0) invert(1);
filter: brightness(0) invert(1);
}<p>
Original:
<img src="http://i.stack.imgur.com/jO8jP.gif" />
</p>
<p>
Filter:
<img src="http://i.stack.imgur.com/jO8jP.gif" class="filter" />
</p>First, brightness(0)makes all image black, except transparent parts, which remain transparent.
首先，brightness(0)使所有图像变黑，透明部分除外，它们保持透明。
Then, invert(1)makes the black parts white.
然后，invert(1)使黑色部分变白。
回答by Daniel Perván
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.
据我所知，遗憾的是没有 CSS 过滤器来为元素着色（也许使用了一些 SVG 过滤器魔法，但我对此有点陌生），即使情况并非如此，过滤器基本上只支持webkit 浏览器。
With that said, you could still work around this and use a canvasto 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.
话虽如此，您仍然可以解决这个问题并使用 acanvas来修改您的图像。基本上，您可以将图像元素绘制到画布上，然后循环遍历像素，将相应的 RGBA 值修改为您想要的颜色。
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.
但是，画布确实有一些限制。最重要的是，您必须确保图像 src 来自与页面相同的域。否则浏览器将不允许您读取或修改画布的像素数据。
Here's a JSFiddlechanging the colour of the JSFiddle logo.
这里有一个的jsfiddle改变的jsfiddle徽标的颜色。
//Base64 source, but any local source will work
var src = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAC0AAAAgCAYAAACGhPFEAAAABGdBTUEAALGPC/xhBQAABzhJREFUWAnNWAtwXFUZ/v9zs4GUJJu+k7tb5DFAGWO1aal1sJUiY3FQQaWidqgPLAMqYzd9CB073VodhCa7KziiFgWhzvAYQCiCD5yK4gOTDnZK2ymdZoruppu0afbu0pBs7p7f7yy96W662aw2QO/Mzj2P//Gd/5z/+89dprfzubnTN332Re+xiKawllxWucm+9O4eCi9xT8ctn45yKd3AXX1BPsu3XIiuY+K5kDmrUA7jORb5m2baLm7uscNrJr9eOF9Je8JAz9ySnFHlq9nEpG6CYx+RdJDQDtKymxT1iWZLFDUy0/kkfDUxzYVzV0hvHZLs946Gph+uBLCRmRDQdjTVwmw9DZCNMPi4KzqWbPX/sxwIu71vlrKq10HnZizwTSFZngj5f1NOx5s7bdB2LHWDEusBOD487LrX9qyd8qpnvJL3zGjqAh+pR4W4RVhu715Vv2U8PTWeQLn5YHvms4qsR4TpH/ImLfhfARvbPaGGrrjTtwjH5hFFfHcgkv5SOZ9mbvxIgwGaZl+8ULGcJ8zOsJa9R1r9B2d8v2eGb1KNieqBhLNz8ekyAoV3VAX985+FvSXEenF8lf9lA7DUUxa0HUl/RTG1EfOUQmUwwCtggDewiHmc1R+Ir/MfKJz/f9tTwn31Nf7qVxlHLR6qXwg7cHXqU/p4hPdUB6Lp55TiXwDYTsrpG12dbdY5t0WLrCSRSVjIItG0dqIAG2jHwlPTmvQdsL3Ajjg3nAq3zIgdS98ZiGV0MJZeWVJs2WNWIJK5hcLh0osuqVTxIAdi6X3w/0LFGoa+AtFMzo5kflix0gQLBiLOZmAYro84RcfSc3NKpFAcliM9eYDdjZ7QO/1mRc+CTapqFX+4lO9TQEPoUpz//anQ5FQphXdizB1QXXk/moOl/JUC7aLMDpQSHj02PdxbG9xybM60u47UjZ4bq290Zm451ky3HSi6kxTKJ9fXHQVvZJm1XTjutYsozw53T1L+2ufBGPMTe/c30M/mD3uChW+c+6tQttthuBnbqMBLKGbydI54/eFQ3b5CWa/dGMl8xFJ0D/rvg1Pjdxil+2XK5b6ZWD15lyfnvYOxTBYs9TrY5NbuUENRUo5EGtGyVUNtBwBfDjA/IDtTkiNRsdYD8O+NcVN2KUfXo3UnukvA6Z3I+mWeY++NpNoAwDvAv1Uiss7oiNBmYD+XraoO0NvnPVnvrbUsA4CcYusPgajzY2/cvN+KtOFl/6w/IWrvdTV/Ktla92KhkNcOxpwPCqm/IgLbEvteW1m4E2/d8iY9AZOXQ/7WxKq6nxq9YNT5OLF6DmAfTHT13EL3XjTk2csXk4bqX2OXWiQ73Jz49tS4N5d/oxoHLr14EzPfAf1IIlS/2oznIx1omLURhL5Qa1oxFuC8EeHb8U6I88bXCwGbuZ61jb2Jgz1XYUHb0b0vEHNWmHE9lNsjWrcmnMhNhYDNnCkmNJSFHFdzte82M1b04HgC6HrYbAPw1pFdNOc4GE334wz9qkihRAdK/0HBub/E1MkhJBiq6V8gq7Htm05OjN2C/z/jCP1xbAlCwcnsAsbdkGHF/trPIcoNrtbjFRNmoama6EgZ42SimRG5FjLHWakNwWjmirLyZpLpKH7TysghZ00OUHNTxFmK2yDNQSKlx7u0Q0GQeLtQdy4rY5zMzqVb/ccoJ/OQMEmoPWW3988to4NY8DxYf6WMDCW6ktuRvFqxmqewgguhdLCcwsic0DMA8lE7kvrYyFhBw446X2B/nRNo739/YnX9azKUXYCg9CtlvdAUyywuEB1p4gh9AzbPZc0mF8Z+sINgn0MIwiVgKcAG6rGlT86AMdqw2n8ppR63o+mveQXCFAxzX2BWD0P6pcT+g3uNlmEDV3JX4iOh1xICdWU2gGXOMXN5HfRhK4IoPxlfXQfmKf+Ajh1I+MEeHMcKzqvoxoZsHsoOXgP+fEkxbw1e2JhB0h2q9tc4OL/fAVdsdd3jnyhklmRo8qGBQXchIvMMKPW7Pt85/SM66CNmDw1mh75cHu6JWZFZxNLNSJTPIM5PuJquKEt3o6zmqyJZH4LTC7CIfTonO5Jr/B2jxIq6jW3OZVYVX4edDSD6e1BAXqwgl/I2miKp+ZayOkT0CjaJww21/2bhznio7uoiL2dQB8HdhoV++ri4AdUdtgfw789mRHspzulXzyCcI1BMVQXgL5LodnP7zFfE+N9/9yOUyedxTn/SFHWWj0ifAY1ANHUleOJRlPqdCUmbO85J1jjxUfkUkgVCsg1/uGw0n/fvFm67LT2NLTLfi98Cke8dpMGl3r9QxVRnPuPrWzaIUmsAtgas0okd6ETh7AYt5d7+BeCbhfKVcQ6CtwgJjjoiP3fdgVbcbY57/otBnxidfndvo6/67BtxUf4kztJsbMg0CJaU9QxN2FskhePQBWr7La6wvzRFarTtyoBgB4hm5M//aAMT2+/Vlfzp81/vywLMWSBN1QAAAABJRU5ErkJggg==";
var canvas = document.getElementById("theCanvas");
var ctx = canvas.getContext("2d");
var img = new Image;
//wait for the image to load
img.onload = function() {
//Draw the original image so that you can fetch the colour data
ctx.drawImage(img,0,0);
var imgData = ctx.getImageData(0, 0, canvas.width, canvas.height);
/*
imgData.data is a one-dimensional array which contains
the respective RGBA values for every pixel
in the selected region of the context
(note i+=4 in the loop)
*/
for (var i = 0; i < imgData.data.length; i+=4) {
imgData.data[i] = 255; //Red, 0-255
imgData.data[i+1] = 255; //Green, 0-255
imgData.data[i+2] = 255; //Blue, 0-255
/*
imgData.data[i+3] contains the alpha value
which we are going to ignore and leave
alone with its original value
*/
}
ctx.clearRect(0, 0, canvas.width, canvas.height); //clear the original image
ctx.putImageData(imgData, 0, 0); //paint the new colorised image
}
//Load the image!
img.src = src;body {
background: green;
}<canvas id="theCanvas"></canvas>