我有一个 Java 脚本，可以自动将图像变灰，并在鼠标悬停时淡入彩色!
我已将以下代码添加到我的 html 页面的标题中!但它不起作用我尝试更改目标图像。
添加此代码后，HTML 或 CSS 中是否需要执行任何操作。
图像应该如何设置才能工作
<script src="jquery.js" type="text/javascript"></script>
<script type="text/javascript">
// 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
$(".menu img").fadeIn(500);
// clone image
$('.menu 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
$('.menu 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();
}
最佳答案
如您所见 - 它运行完美 http://jsfiddle.net/8aSmM/
问题可能来自:
- 您的浏览器不支持 Canvas
- 您的图片正在从另一个域加载。阅读此https://developer.mozilla.org/en/Canvas_tutorial/Using_images#Using_images_from_other_domains上面示例中的图片来自 jsfiddle。
Although you can use images without CORS approval in your canvas, doing so taints the canvas. Once a canvas has been tainted, you can no longer pull data back out of the canvas. For example, you can no longer use the canvas toBlob(), toDataURL(), or getImageData() methods; doing so will throw a security error.
关于javascript - 如何设置应在此代码下的目标图像，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/9528715/