DIV CSS 佈局教程網

HTML5和jQuery實現彩圖變灰與還原，請使用支持HTML5的浏覽器體驗。


效果預覽：
http:///keleyi/phtml/image/2/

效果圖片：


代碼：

<script type="text/javascript">

// $(".item img").css({"display":"none");

// On window load. This waits until images have loaded which is essential
$(window).load(function () {

// Fade in images so there isn't a color "pop" document load and then on window load
$(".item img").animate({ opacity: 1 }, 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();
}

</script>