CSS Multiple Backgrounds
In this chapter you will learn how to add
multiple background images to one element.
You will also learn about the following
properties:
- background-size
- background-origin
- background-clip
CSS Multiple Backgrounds
CSS allows you to add
multiple background images for an element, through the background-image property.
The different background
images are separated by commas, and the images are stacked on top of each
other, where the first image is closest to the viewer.
The following example has
two background images, the first image is a flower (aligned to the bottom and
right) and the second image is a paper background (aligned to the top-left
corner):
Example
#example1 {
background-image: url(img_flwr.gif), url(paper.gif);
background-position: right bottom, left top;
background-repeat: no-repeat, repeat;
}
Multiple background images
can be specified using either the individual background properties (as above)
or the background shorthand property.
The following example uses
the background shorthand
property (same result as example above):
Example
#example1 {
background: url(img_flwr.gif) right bottom no-repeat,
url(paper.gif) left top repeat;
}
CSS Background Size
The CSS background-size property
allows you to specify the size of background images.
The size can be specified
in lengths, percentages, or by using one of the two keywords: contain or cover.
The following example
resizes a background image to much smaller than the original image (using
pixels):
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Here is the code:
Example
#div1 {
background: url(img_flower.jpg);
background-size: 100px 80px;
background-repeat: no-repeat;
}
The two other possible
values for background-size are contain and cover.
The contain keyword
scales the background image to be as large as possible (but both its width and
its height must fit inside the content area). As such, depending on the
proportions of the background image and the background positioning area, there
may be some areas of the background which are not covered by the background
image.
The cover keyword
scales the background image so that the content area is completely covered by
the background image (both its width and height are equal to or exceed the
content area). As such, some parts of the background image may not be visible
in the background positioning area.
The following example
illustrates the use of contain and cover:
Example
#div1 {
background: url(img_flower.jpg);
background-size: contain;
background-repeat: no-repeat;
}
#div2 {
background: url(img_flower.jpg);
background-size: cover;
background-repeat: no-repeat;
}
Define Sizes of Multiple Background Images
The background-size property
also accepts multiple values for background size (using a comma-separated
list), when working with multiple backgrounds.
The following example has
three background images specified, with different background-size value for
each image:
Example
#example1 {
background: url(img_tree.gif) left top no-repeat, url(img_flwr.gif)
right bottom no-repeat, url(paper.gif) left top repeat;
background-size: 50px, 130px, auto;
}
Full Size Background Image
Now we want to have a
background image on a website that covers the entire browser window at all
times.
The requirements are as
follows:
- Fill
the entire page with the image (no white space)
- Scale
image as needed
- Center
image on page
- Do
not cause scrollbars
The following example shows
how to do it; Use the <html> element (the <html> element is always
at least the height of the browser window). Then set a fixed and centered
background on it. Then adjust its size with the background-size property:
Example
html {
background: url(img_man.jpg) no-repeat center fixed;
background-size: cover;
}
Hero Image
You could also use
different background properties on a <div> to create a hero image (a
large image with text), and place it where you want.
Example
.hero-image {
background: url(img_man.jpg) no-repeat center;
background-size: cover;
height: 500px;
position: relative;
}
CSS background-origin Property
The CSS background-origin property
specifies where the background image is positioned.
The property takes three
different values:
- border-box
- the background image starts from the upper left corner of the border
- padding-box
- (default) the background image starts from the upper left corner of the
padding edge
- content-box
- the background image starts from the upper left corner of the content
The following example
illustrates the background-origin property:
Example
#example1 {
border: 10px solid black;
padding: 35px;
background: url(img_flwr.gif);
background-repeat: no-repeat;
background-origin: content-box;
}
CSS background-clip Property
The CSS background-clip property
specifies the painting area of the background.
The property takes three
different values:
- border-box
- (default) the background is painted to the outside edge of the border
- padding-box
- the background is painted to the outside edge of the padding
- content-box
- the background is painted within the content box
The following example
illustrates the background-clip property:
Example
#example1 {
border: 10px dotted black;
padding: 35px;
background: yellow;
background-clip: content-box;
}
CSS Advanced Background Properties
|
Property |
Description |
|
background |
A shorthand property for
setting all the background properties in one declaration |
|
background-clip |
Specifies the painting
area of the background |
|
background-image |
Specifies one or more
background images for an element |
|
background-origin |
Specifies where the
background image(s) is/are positioned |
|
background-size |
Specifies the size of the
background image(s) |
