background-size

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

배경 이미지로 덮히지 않은 공간은 background-color 속성으로 채워져있고, 투명/반투명인 배경 이미지 뒤에도 배경 색이 보여질 것입니다.

구문

/* 키워드 값 */
background-size: cover;
background-size: contain;

/* 단일 값 구문 */
/* 이미지 너비 (높이는 'auto'이 됨) */
background-size: 50%;
background-size: 3.2em;
background-size: 12px;
background-size: auto;

/* 두개 값 구문 */
/* 첫번째 값: 이미지 너비, 두번째 값: 이미지 높이 */
background-size: 50% auto;
background-size: 3em 25%;
background-size: auto 6px;
background-size: auto auto;

/* 여러 배경들 */
background-size: auto, auto; /* `auto auto`와 혼동하지 말 것 */
background-size: 50%, 25%, 25%;
background-size: 6px, auto, contain;

/* 전역 값 */
background-size: inherit;
background-size: initial;
background-size: unset;

 background-size 속성은 다음 방법으로 지정될 수 있습니다. 

• 키워드 값인 contain 또는 cover 를 사용합니다.
• 너비 값만 사용하는 경우, 높이는 기본적으로 auto로 설정됩니다.
• 너비와 높이 값을 모두 사용하는 경우, 첫번째 값은 너비로, 두번째 값은 높이로 설정됩니다. 각 값은 <length>, <percentage>, 또는 auto가 될 수 있습니다.

여러 배경 이미지의 사이즈를 지정하려면, 각각의 값을 쉼표로 구분하세요.

값

contain

Scales the image as large as possible without cropping or stretching the image.

cover

Scales the image as large as possible without stretching the image. If the proportions of the image differ from the element, it is cropped either vertically or horizontally so that no empty space remains.

auto

Scales the background image in the corresponding direction such that its intrinsic proportions are maintained.

<length>

Stretches the image in the corresponding dimension to the specified length. Negative values are not allowed.

<percentage>

Stretches the image in the corresponding dimension to the specified percentage of the background positioning area. The background positioning area is determined by the value of background-origin (by default, the padding box). However, if the background's background-attachment value is fixed, the positioning area is instead the entire viewport. Negative values are not allowed.

Intrinsic dimensions and proportions

The computation of values depends on the image's intrinsic dimensions (width and height) and intrinsic proportions (width-to-height ratio). These attributes are as follows:

• A bitmap image (such as JPG) always has intrinsic dimensions and proportions.
• A vector image (such as SVG) does not necessarily have intrinsic dimensions. If it has both horizontal and vertical intrinsic dimensions, it also has intrinsic proportions. If it has no dimensions or only one dimension, it may or may not have proportions.
• CSS <gradient>s have no intrinsic dimensions or intrinsic proportions.
• Background images created with the element() function use the intrinsic dimensions and proportions of the generating element.

Based on the intrinsic dimensions and proportions, the rendered size of the background image is computed as follows:

If both components of background-size are specified and are not auto:

The background image is rendered at the specified size.

If the background-size is contain or cover:

While preserving its intrinsic proportions, the image is rendered at the largest size contained within, or covering, the background positioning area. If the image has no intrinsic proportions, then it's rendered at the size of the background positioning area.

If the background-size is auto or auto auto:

• If the image has both horizontal and vertical intrinsic dimensions, it's rendered at that size.
• If the image has no intrinsic dimensions and has no intrinsic proportions, it's rendered at the size of the background positioning area.
• If the image has no intrinsic dimensions but has intrinsic proportions, it's rendered as if contain had been specified instead.
• If the image has only one intrinsic dimension and has intrinsic proportions, it's rendered at the size corresponding to that one dimension. The other dimension is computed using the specified dimension and the intrinsic proportions.
• If the image has only one intrinsic dimension but has no intrinsic proportions, it's rendered using the specified dimension and the other dimension of the background positioning area.

Note: SVG images have a preserveAspectRatio attribute that defaults to the equivalent of contain. In Firefox 43, as opposed to Chrome 52, an explicit background-size causes preserveAspectRatio to be ignored.

If the background-size has one auto component and one non-auto component:

• If the image has intrinsic proportions, it's stretched to the specified dimension. The unspecified dimension is computed using the specified dimension and the intrinsic proportions.
• If the image has no intrinsic proportions, it's stretched to the specified dimension. The unspecified dimension is computed using the image's corresponding intrinsic dimension, if there is one. If there is no such intrinsic dimension, it becomes the corresponding dimension of the background positioning area.

Formal syntax

<bg-size>#
where 
<bg-size> = [ <length-percentage> | auto ]{1,2} | cover | contain
where 
<length-percentage> = <length> | <percentage>

Examples

Please see Scaling background images for examples.

Notes

If you use a <gradient> as the background and specify a background-size to go with it, it's best not to specify a size that uses a single auto component, or is specified using only a width value (for example, background-size: 50%). Rendering of <gradient>s in such cases changed in Firefox 8, and at present is generally inconsistent across browsers, which do not all implement rendering in full accordance with the CSS3 background-size specification and with the CSS3 Image Values gradient specification.

.gradient-example {
  width: 50px;
  height: 100px;
  background-image: linear-gradient(blue, red);

  /* Not safe to use */
  background-size: 25px;
  background-size: 50%;
  background-size: auto 50px;
  background-size: auto 50%;

  /* Safe to use */
  background-size: 25px 50px;
  background-size: 50% 50%;
}

Note that it's particularly not recommended to use a pixel dimension and an auto dimension with a <gradient>, because it's impossible to replicate rendering in versions of Firefox prior to 8, and in browsers not implementing Firefox 8's rendering, without knowing the exact size of the element whose background is being specified.

Specifications

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

See also

• Scaling background images
• Scaling of SVG backgrounds
• object-fit