Question

当鼠标悬停在div上时，如何使图像淡出灰度？

这是页面http://www.stirringminds.com/partners/

HTML：

<div class="col-xs-4 dealsdiv" id="businessfltr" style="background-color:#fff;border:1px solid #DDD;border-radius:4px;margin:10px;"><img class="dealsimg" src="http://13.126.32.0/wp-content/uploads/2017/05/aws_logo_web_300px.png"/><span style="position:relative;bottom:15%;left:7%;color:#000;">Amazon Web Services</span><br><span style="position:relative;left:48.5%;bottom:50%;padding-right:-100px;">$1000 credits for 1 year.</span></div>

CSS：

.dealsdiv {
    height: 100px;
}

.dealsimg {
  width:150px;
  height:auto;
  position: relative;
  top: 50%;
  transform: translateY(-50%);
  -webkit-filter: grayscale(100%); /* Safari 6.0 - 9.0 */
  filter: grayscale(100%);
}

Answer 1

.dealsdiv {
    height: 100px;

}

.dealsimg {
  width:150px;
  height:auto;
  position: relative;
  top: 50%;
  transform: translateY(-50%);
  -webkit-filter: grayscale(100%); /* Safari 6.0 - 9.0 */
  filter: grayscale(100%);
  transition: filter 400ms ease-in-out; //this is optional. change the duration if you want.

}

.dealsdiv:hover .dealsimg {
filter: grayscale(0);
}

Answer 2

使用transition

.dealsimg {
    -webkit-transition: -webkit-filter 300ms;
    transition:filter 300ms;
}
.dealsdiv:hover .dealsimg{
  -webkit-filter: grayscale(0%); /* Safari 6.0 - 9.0 */
  filter: grayscale(0%);
}

Answer 3

这是我在StackOverflow上的第一个答案，但我相信我至少能指出你正确的方向。

对此的一个答案是使用JQuery和HTML canvas元素。

// waits until all images have loaded
$(window).load(function(){

//Fade in images so there isn't a color "pop" document load and then on window load
    $(".item img").fadeIn(500);

    // clone image
    $('.item img').each(function(){
        var el = $(this);
        el.css({"position":"absolute"}).wrap("<div class='img_wrapper' style='display: inline-block'>").clone().addClass('img_grayscale').css({"position":"absolute","z-index":"998","opacity":"0"}).insertBefore(el).queue(function(){
            var el = $(this);
            el.parent().css({"width":this.width,"height":this.height});
            el.dequeue();
        });
        this.src = grayscale(this.src);
    });

    // Fade image 
    $('.item img').mouseover(function(){
        $(this).parent().find('img:first').stop().animate({opacity:1}, 1000);
    })
    $('.img_grayscale').mouseout(function(){
        $(this).stop().animate({opacity:0}, 1000);
    });     
});

// Grayscale w canvas method
function grayscale(src){
    var canvas = document.createElement('canvas');
    var ctx = canvas.getContext('2d');
    var imgObj = new Image();
    imgObj.src = src;
    canvas.width = imgObj.width;
    canvas.height = imgObj.height; 
    ctx.drawImage(imgObj, 0, 0); 
    var imgPixels = ctx.getImageData(0, 0, canvas.width, canvas.height);
    for(var y = 0; y < imgPixels.height; y++){
        for(var x = 0; x < imgPixels.width; x++){
            var i = (y * 4) * imgPixels.width + x * 4;
            var avg = (imgPixels.data[i] + imgPixels.data[i + 1] + imgPixels.data[i + 2]) / 3;
            imgPixels.data[i] = avg; 
            imgPixels.data[i + 1] = avg; 
            imgPixels.data[i + 2] = avg;
        }
    }
    ctx.putImageData(imgPixels, 0, 0, 0, 0, imgPixels.width, imgPixels.height);
    return canvas.toDataURL();
}

SOURCE＆lt; - 来自达西克拉克的一个很好的步行路程，demo（我想）正是你正在寻找的。

注意：使用上面的代码，请记住：

你应该设置目标图像（例如：.post-img，img，.gallery img等）

您可以更改动画速度（即1000 = 1秒）

在mouseover div

3 个答案: