HTML/CSS - create alpha mask over image

Question

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.

Something like this: http://imgur.com/fqtc9.png

I prefer to do this with CSS/HTML/JS - not images. Any thoughts on where to start? Thanks.

Answer 1

you could do something like this for example : Example

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

@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; 

}

Answer 2

Ah — based on your comment on antyrat's answer, your best bet is to create a PNG image that contains the effect (ie a semi-transparent white shape), and position it over the top of your actual image using CSS ( position:absolute and z-index will be involved).

You can't currently create non-square shapes using HTML and CSS alone.

Answer 3

I know that you are asking specifically for a CSS/JavaScript solution, and I'm sure you have your reasons.

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.

Answer 4

Start with jQuery . For example see fadeIn function.

For static alpha mask over image use opacity css property:

.myimage {
  filter:progid:DXImageTransform.Microsoft.Alpha(opacity=50); 
  -moz-opacity: 0.5;
  -khtml-opacity: 0.5;
  opacity: 0.5;
}

Answer 5

jQuery animate功能（具有不透明度）应该/可能能够处理，但是如果你简单地淡化覆盖，antyrat的答案应该也可以。