What does cover mean in css

cover in CSS specifies that the background image completely covers the container and maintains the original aspect ratio. It needs to be used as the value of the background size attribute when used, and can also be used with contain to prevent image deformation. Applicable scenarios include full-screen backgrounds, hero areas, and sliders, but be aware that images may be stretched, cropped, or blurred.

The meaning of cover in CSS

cover is the keyword used to set the background image attribute in CSS. It Specifies that the image will completely cover the container while maintaining the image's original aspect ratio. This means that the image will be stretched or reduced to fill the container without being cropped or distorted.

How to use cover

When using cover, you need to specify it as the value of the background-size attribute:

background-size: cover;

You can also use it with contain Used together, contain specifies that the image will be scaled to fill the container, but not exceed its original aspect ratio, which prevents the image from being stretched out of shape:

background-size: contain;

When to use cover

cover is suitable for situations where the background image needs to completely cover the container, for example:

• Full-screen background: Use cover to create a full-screen background image, and the image will automatically scale to accommodate different screen sizes.
• Hero area: The hero area usually contains a large and eye-catching image, using cover can ensure that the image completely fills the area while maintaining its aspect ratio.
• Slider: Slider components usually use cover to ensure that the image completely covers the slider area.

Notes

You should pay attention to the following points when using cover:

• The image may be stretched or reduced. Image quality may be reduced.
• If the aspect ratio of the image is different from the aspect ratio of the container, the image will be stretched or cropped to fit the container.
• In some cases, cover will cause the image to be blurry.

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