How to use CSS Viewport units to implement adaptive background images

How to use CSS Viewport units to implement adaptive background images

Background images play a very important role in web design and can add beauty and appeal to web pages . However, implementing adaptive background images becomes a challenge due to different devices and screen sizes. In this article, we’ll explain how to use CSS Viewport units to implement adaptive background images, and give specific code examples.

CSS Viewport units are units that define length relative to the dimensions of the browser window (i.e., the viewport). There are two commonly used Viewport units, vw and vh. Among them, 1vw is equal to one percent of the viewport width, and 1vh is equal to one percent of the viewport height. Below we will use these two units to implement adaptive background images.

First, we need to prepare a background image, which can be set as the background image of the web page using the following code:

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

Next, we use vw units to set the width of the background image. For example, if we want the width of the background image to occupy 50% of the width of the viewport, we can use the following code:

body {
  background-image: url('background.jpg');
  background-size: 50vw;
  background-repeat: no-repeat;
  background-position: center;
}

By setting the background-size property to 50vw, the width of the background image will automatically be based on the width of the viewport. Adjustment to achieve adaptive effect.

Similarly, we can use vh units to set the height of the background image. For example, if we want the height of the background image to occupy 50% of the viewport height, we can use the following code:

body {
  background-image: url('background.jpg');
  background-size: cover;
  background-repeat: no-repeat;
  background-position: center;
  height: 100vh;
}

By setting height: 100vh, the height of the background image will automatically adjust according to the height of the viewport, so that It fills the entire viewport.

In addition, we can also combine vw and vh units to set the width and height of the background image at the same time to achieve a more free adaptive effect. For example, if we want the width and height of the background image to occupy 50% of the viewport, we can use the following code:

body {
  background-image: url('background.jpg');
  background-size: 50vw 50vh;
  background-repeat: no-repeat;
  background-position: center;
}

By setting background-size: 50vw 50vh, the width and height of the background image will be based on the viewport. The size of the mouth is adjusted to achieve a more precise adaptive effect.

In summary, using CSS Viewport units to implement adaptive background images is very simple and practical. By setting the background-size property to vw or vh units, we can easily achieve adaptive effects on the background image. By using these units flexibly, we can make the background image display perfectly on different devices and screen sizes, thereby improving the user experience of the web page.

I hope this article was helpful and I wish you success in using CSS Viewport units to implement adaptive background images!

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