Set background size image css

background-size

The background-size CSS property sets the size of the element’s background image. The image can be left to its natural size, stretched, or constrained to fit the available space.

Try it

Spaces not covered by a background image are filled with the background-color property, and the background color will be visible behind background images that have transparency/translucency.

Syntax

/* Keyword values */ background-size: cover; background-size: contain; /* One-value syntax */ /* the width of the image (height becomes 'auto') */ background-size: 50%; background-size: 3.2em; background-size: 12px; background-size: auto; /* Two-value syntax */ /* first value: width of the image, second value: height */ background-size: 50% auto; background-size: 3em 25%; background-size: auto 6px; background-size: auto auto; /* Multiple backgrounds */ background-size: auto, auto; /* Not to be confused with `auto auto` */ background-size: 50%, 25%, 25%; background-size: 6px, auto, contain; /* Global values */ background-size: inherit; background-size: initial; background-size: revert; background-size: revert-layer; background-size: unset; 

The background-size property is specified in one of the following ways:

  • Using the keyword values contain or cover .
  • Using a width value only, in which case the height defaults to auto .
  • Using both a width and a height value, in which case the first sets the width and the second sets the height. Each value can be a , a , or auto .
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To specify the size of multiple background images, separate the value for each one with a comma.

Values

Scales the image as large as possible within its container without cropping or stretching the image. If the container is larger than the image, this will result in image tiling, unless the background-repeat property is set to no-repeat .

Scales the image (while preserving its ratio) to the smallest possible size to fill the container (that is: both its height and width completely cover the container), leaving no empty space. If the proportions of the background differ from the element, the image is cropped either vertically or horizontally.

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

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

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 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.

Note: In Gecko, background images created using the element() function are currently treated as images with the dimensions of the element, or of the background positioning area if the element is SVG, with the corresponding intrinsic proportion. This is non-standard behavior.

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 ; an explicit background-size causes preserveAspectRatio to be ignored.

    • 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.

    Note: Background sizing for vector images that lack intrinsic dimensions or proportions is not yet fully implemented in all browsers. Be careful about relying on the behavior described above, and test in multiple browsers to be sure the results are acceptable.

    Formal definition

    Initial value auto auto
    Applies to all elements. It also applies to ::first-letter and ::first-line .
    Inherited no
    Percentages relative to the background positioning area
    Computed value as specified, but with relative lengths converted into absolute lengths
    Animation type a repeatable list of

    Formal syntax

    Examples

    Tiling a large image

    Let’s consider a large image, a 2982×2808 Firefox logo image. We want to tile four copies of this image into a 300×300-pixel element. To do this, we can use a fixed background-size value of 150 pixels.

    HTML

    div class="tiledBackground">div> 

    CSS

    .tiledBackground  background-image: url(https://www.mozilla.org/media/img/logos/firefox/logo-quantum.9c5e96634f92.png); background-size: 150px; width: 300px; height: 300px; border: 2px solid; color: pink; > 

    Result

    Specifications

    Browser compatibility

    BCD tables only load in the browser

    See also

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    Источник

    CSS background-size Property

    Specify the size of a background-image with «auto» and in pixels:

    #example1 <
    background: url(mountain.jpg);
    background-repeat: no-repeat;
    background-size: auto;
    >

    #example2 background: url(mountain.jpg);
    background-repeat: no-repeat;
    background-size: 300px 100px;
    >

    More «Try it Yourself» examples below.

    Definition and Usage

    The background-size property specifies the size of the background images.

    There are four different syntaxes you can use with this property: the keyword syntax («auto», «cover» and «contain»), the one-value syntax (sets the width of the image (height becomes «auto»), the two-value syntax (first value: width of the image, second value: height), and the multiple background syntax (separated with comma).

    Default value: auto
    Inherited: no
    Animatable: yes. Read about animatable Try it
    Version: CSS3
    JavaScript syntax: object.style.backgroundSize=»60px 120px» Try it

    Browser Support

    The numbers in the table specify the first browser version that fully supports the property.

    Numbers followed by -webkit-, -moz-, or -o- specify the first version that worked with a prefix.

    CSS Syntax

    Property Values

    Value Description Demo
    auto Default value. The background image is displayed in its original size Demo ❯
    length Sets the width and height of the background image. The first value sets the width, the second value sets the height. If only one value is given, the second is set to «auto». Read about length units Demo ❯
    percentage Sets the width and height of the background image in percent of the parent element. The first value sets the width, the second value sets the height. If only one value is given, the second is set to «auto» Demo ❯
    cover Resize the background image to cover the entire container, even if it has to stretch the image or cut a little bit off one of the edges Demo ❯
    contain Resize the background image to make sure the image is fully visible Demo ❯
    initial Sets this property to its default value. Read about initial
    inherit Inherits this property from its parent element. Read about inherit

    More Examples

    Example

    Specify the size of a background image with percent:

    #example1 <
    background: url(mountain.jpg);
    background-repeat: no-repeat;
    background-size: 100% 100%;
    >

    #example2 background: url(mountain.jpg);
    background-repeat: no-repeat;
    background-size: 75% 50%;
    >

    Example

    Specify the size of a background image with «cover»:

    Example

    Specify the size of a background image with «contain»:

    Example

    Here we have two background images. We specify the size of the first background image with «contain», and the second background-image with «cover»:

    #example1 <
    background: url(img_tree.gif), url(mountain.jpg);
    background-repeat: no-repeat;
    background-size: contain, cover;
    >

    Example

    Use different background properties to create a «hero» image:

    .hero-image <
    background-image: url(«photographer.jpg»); /* The image used */
    background-color: #cccccc; /* Used if the image is unavailable */
    height: 500px; /* You must set a specified height */
    background-position: center; /* Center the image */
    background-repeat: no-repeat; /* Do not repeat the image */
    background-size: cover; /* Resize the background image to cover the entire container */
    >

    Источник

    background — size

    Нужно чтобы фоновая картинка заняла всю площадь элемента? Вам нужно это свойство!

    Время чтения: меньше 5 мин

    Кратко

    Скопировать ссылку «Кратко» Скопировано

    Свойство background — size позволяет изменять размер фонового изображения. Если фоновая картинка не совпадает по размеру с размерами блока, то при помощи этого свойства можно сделать так, чтобы она, картинка занимала всю площадь блока или, наоборот, была определённого размера.

    Пример

    Скопировать ссылку «Пример» Скопировано

    Создадим блок и в качестве фона зададим ему красивую панораму:

    Фон с красивой панорамой

     div class="element">div>      
     .element  height: 100vh; background-color: #f1f1f1; background-image: url("landscape.jpg"); background-repeat: no-repeat;> .element  height: 100vh; background-color: #f1f1f1; background-image: url("landscape.jpg"); background-repeat: no-repeat; >      

    Примеры background-size

    Попробуйте поменять размеры фоновой картинки и посмотреть, как будет меняться фоновый паттерн.

    Источник

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