Javascript HTML/CSS - 在图像上创建 alpha 蒙版
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HTML/CSS - create alpha mask over image
提问by sa125
I'd like to create an effect in a site I'm building where an image is masked by an overlay. The overlay should create a “fade out” effect — I don't actually want anything animated, but the overlay should make the image look as if it's fading to the background colour at the edges.
我想在我正在构建的站点中创建一个效果，其中图像被覆盖层掩盖。覆盖应该创建一个“淡出”效果——我实际上并不想要任何动画，但覆盖应该使图像看起来好像它正在边缘的背景颜色褪色。
Something like this: http://imgur.com/fqtc9.png
像这样的东西：http: //imgur.com/fqtc9.png
I prefer to do this with CSS/HTML/JS - not images. Any thoughts on where to start? Thanks.
我更喜欢用 CSS/HTML/JS 来做这件事——而不是图像。关于从哪里开始的任何想法？谢谢。
采纳答案by Nate Nolting
you could do something like this for example : Example
你可以做这样的事情，例如：示例
html
html
<div class="photo_container">
<div class="photo">
<img src="/lakenwoods/images/mockup-photo.png" width="540" height="463" /></div>
<div class="overlay">
<div class="content">
<h1>Welcome to Lake-N-Woods Realty</h1>
<p>
We are a Diverse and Highly Effective Real Estate Company, Dedicated to Satisfying all of our Clients Needs. We Specialize in Recreational, Rural and Investment Property throughout Bemidji and North Central Minnesota.
</p>
</div>
</div>
<div class="clear">
</div>
</div>
CSS
CSS
@charset "utf-8";
/* CSS Document */
.clear {
clear:both;
}
.photo_container {
position: relative;
width: 540px;
height: 463px;
overflow:hidden;
margin: 0; padding:0;
}
.photo_container .photo {
z-index:1;
}
.photo_container .overlay {
width: 540px;
height: 463px;
background: url(/lakenwoods/images/mockup-overlay.png) no-repeat top center;
position:absolute;
bottom: 0;
left: 0;
z-index:10;
}
.photo_container .overlay .content h1 {
position:absolute;
top: 310px;
left: 34px;
font-family: Helvetica, Helvetica Neue, Arial, sans-serif;
font-size:18px;
color: #fff;
font-weight: 700;
width: 315px;
}
.photo_container .overlay .content p {
position:absolute;
top: 335px;
left: 34px;
font-family: Helvetica, Helvetica Neue, Arial, sans-serif;
font-size:12px;
color: #fff;
width: 315px;
line-height: 1.4em;
}
回答by Paul D. Waite
Ah — based on your comment on antyrat's answer, your best bet is to create a PNG image that contains the effect (i.e. a semi-transparent white shape), and position it over the top of your actual image using CSS (position:absoluteand z-indexwill be involved).
啊——根据你对 antyrat 的回答的评论，你最好的办法是创建一个包含效果的 PNG 图像（即半透明的白色形状），并使用 CSS将其放置在实际图像的顶部（position:absolute并且z-index将涉及）。
You can't currently create non-square shapes using HTML and CSS alone.
您目前无法单独使用 HTML 和 CSS 创建非方形形状。
回答by JohnB
I know that you are asking specifically for a CSS/JavaScript solution, and I'm sure you have your reasons.
我知道您特别要求 CSS/JavaScript 解决方案，我相信您有自己的理由。
Nevertheless, I just wanted to throw out the simple solution of a single faded image file like you already posted in your question with no fancy programmed effects.
尽管如此，我只是想抛出一个简单的褪色图像文件的简单解决方案，就像你已经在你的问题中发布的那样，没有花哨的编程效果。
回答by antyrat
回答by smdrager
The jQuery animatefunction (with opacity) should/may be able to handle that, though antyrat's answer should work as well if you simply fadein the overlay.
jQueryanimate函数（具有不透明度）应该/可能能够处理这个问题，尽管如果您只是淡入叠加层，antyrat 的答案也应该有效。
