我有很多幻灯片,每个都显示一个项目。我想让所有未选择的幻灯片变成灰色(不仅仅是淡化它们的不透明度或在它们上面放一层乳白色的覆盖物,我可以这样做),以使当前选择的幻灯片在视觉上脱颖而出。它应该适用于当前的 webkit 浏览器和 IE8 以上。我尝试使用画布将它们变灰,但它破坏了我网站上的幻灯片和其他内容。是否有另一种方法通过 CSS 和 jQuery 使图像/幻灯片变灰?
要是这-webkit-filter: grayscale(100%);
能在 Safari、Chrome、Firefox 和 IE>=8 中工作就好了……
<script type="text/javascript">
$(window).load(function(){
$('.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);
});
$('.item img').mouseover(function(){
$(this).parent().find('img:first').stop().animate({opacity:1}, 1000);
})
$('.img_grayscale').mouseout(function(){
$(this).stop().animate({opacity:0}, 1000);
});
});
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();
}
</script>