Scaling and Stretching CSS Backgrounds

In web design, it’s often necessary to scale or stretch a background image to fit its container. This can be achieved using various techniques in CSS. In this tutorial, we’ll explore how to use the background-size property to achieve this effect.

Introduction to `background-size`

The background-size property is used to specify the size of a background image. It can take one or two values: the first value sets the width, and the second value sets the height. If only one value is provided, the second value defaults to auto.

Scaling Background Images

To scale a background image, you can use the following values for background-size:

cover: scales the image to cover the entire container while maintaining its aspect ratio.
contain: scales the image to fit within the container while maintaining its aspect ratio.
100% 100%: scales the image to fill the container, stretching it if necessary.

Here’s an example of using background-size to scale a background image:

.container {
    background-image: url('image.jpg');
    background-size: cover;
}

This will scale the background image to cover the entire container while maintaining its aspect ratio.

Stretching Background Images

If you want to stretch a background image to fill its container, you can use the following values for background-size:

100% 100%: stretches the image to fill the container.
auto 100%: stretches the image horizontally to fill the container while maintaining its aspect ratio vertically.

Here’s an example of using background-size to stretch a background image:

.container {
    background-image: url('image.jpg');
    background-size: 100% 100%;
}

This will stretch the background image to fill the entire container, potentially distorting it if the aspect ratio is not maintained.

Browser Support

The background-size property is supported in most modern browsers, including Chrome, Firefox, Safari, and Internet Explorer 9+. However, older versions of Internet Explorer may require additional techniques or workarounds to achieve similar effects.

Alternative Techniques

If you need to support older browsers, you can use alternative techniques such as using an img element with CSS styling:

<div id="background">
    <img src="image.jpg" class="stretch" alt="" />
</div>

And the corresponding CSS:

#background {
    width: 100%;
    height: 100%;
    position: absolute;
    left: 0px;
    top: 0px;
    z-index: 0;
}

.stretch {
    width: 100%;
    height: 100%;
}

This technique can be useful for supporting older browsers, but it may not provide the same level of control as using background-size.

Conclusion

In conclusion, scaling and stretching CSS backgrounds is a powerful technique that can add visual interest to your web designs. By using the background-size property, you can achieve a range of effects, from scaling images to cover or contain their containers to stretching them to fill the available space. With its wide browser support and flexibility, background-size is an essential tool in any web designer’s toolkit.

Introduction to background-size