Image Gallery
The following image gallery is created with CSS:
Example
<html>
<head>
<style type="text/css">
div.img
{
margin:2px;
border:1px solid #0000ff;
height:auto;
width:auto;
float:left;
text-align:center;
}
div.img img
{
display:inline;
margin:3px;
border:1px solid #ffffff;
}
div.img a:hover img
{
border:1px solid #0000ff;
}
div.desc
{
text-align:center;
font-weight:normal;
width:120px;
margin:2px;
}
</style>
</head>
<body>
<div class="img">
<a target="_blank" href="klematis_big.htm">
<img src="klematis_small.jpg" alt="Klematis" width="110" height="90" />
</a>
<div class="desc">Add a description of the image here</div>
</div>
<div class="img">
<a target="_blank" href="klematis2_big.htm">
<img src="klematis2_small.jpg" alt="Klematis" width="110" height="90" />
</a>
<div class="desc">Add a description of the image here</div>
</div>
<div class="img">
<a target="_blank" href="klematis3_big.htm">
<img src="klematis3_small.jpg" alt="Klematis" width="110" height="90" />
</a>
<div class="desc">Add a description of the image here</div>
</div>
<div class="img">
<a target="_blank" href="klematis4_big.htm">
<img src="klematis4_small.jpg" alt="Klematis" width="110" height="90" />
</a>
<div class="desc">Add a description of the image here</div>
</div>
</body>
</html>
Creating transparent images with CSS is easy.
HINT: The CSS opacity property is a part of the W3C CSS3 recommendation.
Example 1 - Creating a Transparent Image
The CSS3 property for transparency is opacity.
First we will show you how to create a transparent image with CSS.
Regular image:
The same image with transparency:
Look at the following CSS:
img
{
opacity:0.4;
filter:alpha(opacity=40); /* For IE8 and earlier */
}
IE9, Firefox, Chrome, Opera, and Safari use the property opacity for transparency. The opacity property can take a value from 0.0 - 1.0. A lower value makes the element more transparent.
IE8 and earlier use filter:alpha(opacity=x). The x can take a value from 0 - 100. A lower value makes the element more transparent.
Example 2 - Image Transparency - Hover Effect
Mouse over the images:
The CSS looks like this:
img
{
opacity:0.4;
filter:alpha(opacity=40); /* For IE8 and earlier */
}
img:hover
{
opacity:1.0;
filter:alpha(opacity=100); /* For IE8 and earlier */
}
The first CSS block is similar to the code in Example 1. In addition, we have added what should happen when a user hover over one of the images. In this case we want the image to NOT be transparent when the user hover over it.
The CSS for this is: opacity=1.
IE8 and earlier: filter:alpha(opacity=100).
When the mouse pointer moves away from the image, the image will be transparent again.
Example 3 - Text in Transparent Box
This is some text that is placed in the transparent box. This is some text that is placed in the transparent box. This is some text that is placed in the transparent box. This is some text that is placed in the transparent box. This is some text that is placed in the transparent box.
The source code looks like this:
<html>
<head>
<style type="text/css">
div.background
{
width:500px;
height:250px;
background:url(klematis.jpg) repeat;
border:2px solid black;
}
div.transbox
{
width:400px;
height:180px;
margin:30px 50px;
background-color:#ffffff;
border:1px solid black;
opacity:0.6;
filter:alpha(opacity=60); /* For IE8 and earlier */
}
div.transbox p
{
margin:30px 40px;
font-weight:bold;
color:#000000;
}
</style>
</head>
<body>
<div class="background">
<div class="transbox">
<p>This is some text that is placed in the transparent box.
This is some text that is placed in the transparent box.
This is some text that is placed in the transparent box.
This is some text that is placed in the transparent box.
This is some text that is placed in the transparent box.
</p>
</div>
</div>
</body>
</html>
First, we create a div element (class="background") with a fixed height and width, a background image, and a border. Then we create a smaller div (class="transbox") inside the first div element. The "transbox" div have a fixed width, a background color, and a border - and it is transparent. Inside the transparent div, we add some text inside a p element.
Image Sprites
An image sprite is a collection of images put into a single image.
A web page with many images can take a long time to load and generates multiple server requests.
Using image sprites will reduce the number of server requests and save bandwidth.
Image Sprites - Simple Example
Instead of using three separate images, we use this single image ("img_navsprites.gif"):
With CSS, we can show just the part of the image we need.
In the following example the CSS specifies which part of the "img_navsprites.gif" image to show:
Example
img.home
{
width:46px;
height:44px;
background:url(img_navsprites.gif) 0 0;
}
Example explained:
- <img class="home" src="img_trans.gif" /> - Only defines a small transparent image because the src attribute cannot be empty. The displayed image will be the background image we specify in CSS
- width:46px;height:44px; - Defines the portion of the image we want to use
- background:url(img_navsprites.gif) 0 0; - Defines the background image and its position (left 0px, top 0px)
This is the easiest way to use image sprites, now we want to expand it by using links and hover effects.
Image Sprites - Create a Navigation List
We want to use the sprite image ("img_navsprites.gif") to create a navigation list.
We will use an HTML list, because it can be a link and also supports a background image:
Example
#navlist{position:relative;}
#navlist li{margin:0;padding:0;list-style:none;position:absolute;top:0;}
#navlist li, #navlist a{height:44px;display:block;}
#home{left:0px;width:46px;}
#home{background:url('img_navsprites.gif') 0 0;}
#prev{left:63px;width:43px;}
#prev{background:url('img_navsprites.gif') -47px 0;}
#next{left:129px;width:43px;}
#next{background:url('img_navsprites.gif') -91px 0;}
Example explained:
- #navlist{position:relative;} - position is set to relative to allow absolute positioning inside it
- #navlist li{margin:0;padding:0;list-style:none;position:absolute;top:0;} - margin and padding is set to 0, list-style is removed, and all list items are absolute positioned
- #navlist li, #navlist a{height:44px;display:block;} - the height of all the images are 44px
Now start to position and style for each specific part:
- #home{left:0px;width:46px;} - Positioned all the way to the left, and the width of the image is 46px
- #home{background:url(img_navsprites.gif) 0 0;} - Defines the background image and its position (left 0px, top 0px)
- #prev{left:63px;width:43px;} - Positioned 63px to the right (#home width 46px + some extra space between items), and the width is 43px.
- #prev{background:url('img_navsprites.gif') -47px 0;} - Defines the background image 47px to the right (#home width 46px + 1px line divider)
- #next{left:129px;width:43px;}- Positioned 129px to the right (start of #prev is 63px + #prev width 43px + extra space), and the width is 43px.
- #next{background:url('img_navsprites.gif') no-repeat -91px 0;} - Defines the background image 91px to the right (#home width 46px + 1px line divider + #prev width 43px + 1px line divider )
Image Sprites - Hover Effect
Now we want to add a hover effect to our navigation list.
Our new image ("xyz") contains three navigation images and three images to use for hover effects:
Because this is one single image, and not six separate files, there will be no loading delay when a user hovers over the image.
We only add three lines of code to add the hover effect:
Example
#home a:hover{background: url('img_navsprites_hover.gif') 0 -45px;}
#prev a:hover{background: url('img_navsprites_hover.gif') -47px -45px;}
#next a:hover{background: url('img_navsprites_hover.gif') -91px -45px;}
Example explained:
Since the list item contains a link, we can use the :hover pseudo-class
#home a:hover{background: transparent url(img_navsprites_hover.gif) 0 -45px;} - For all three hover images we specify the same background position, only 45px further down.
