radial-gradient() - CSS: Cascading Style Sheets 编辑

The radial-gradient() CSS function creates an image consisting of a progressive transition between two or more colors that radiate from an origin. Its shape may be a circle or an ellipse. The function's result is an object of the <gradient> data type, which is a special kind of <image>.

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.

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.

Syntax

/* A gradient at the center of its container,
   starting red, changing to blue, and finishing green */
radial-gradient(circle at center, red 0, blue, green 100%)

A radial gradient is specified by indicating the center of the gradient (where the 0% ellipse will be) and the size and shape of the ending shape (the 100% ellipse). 

Values

<position>

The position of the gradient, interpreted in the same way as background-position or transform-origin. If unspecified, it defaults to center.

<ending-shape>

The gradient's ending-shape. The value can be circle (meaning that the gradient's shape is a circle with a constant radius) or ellipse (meaning that the shape is an axis-aligned ellipse). If unspecified, it defaults to ellipse.

<size>

Determines the size of the gradient’s ending shape. If omitted it defaults to farthest-corner. It can be given explicitly or by keyword. For the purpose of the keyword definitions, consider the gradient box edges as extending infinitely in both directions, rather than being finite line segments.

Both circle and ellipse gradients accept the following keywords for their <size>:

Keyword	Description
closest-side	The gradient's ending shape meets the side of the box closest to its center (for circles) or meets both the vertical and horizontal sides closest to the center (for ellipses).
closest-corner	The gradient's ending shape is sized so that it exactly meets the closest corner of the box from its center.
farthest-side	Similar to closest-side, except the ending shape is sized to meet the side of the box farthest from its center (or vertical and horizontal sides).
farthest-corner	The default value, the gradient's ending shape is sized so that it exactly meets the farthest corner of the box from its center.

If <ending-shape> is specified as circle or is omitted, the size may be given explicitly as a <length>, which provides an explicit circle radius. Negative values are invalid.

If <ending-shape> is specificed as ellipse or is ommitted, the size may be given as a <length-percentage> with two values to provide an explicit ellipse size. The first value represents the horizontal radius, the second the vertical radius. Percentages values are relative to the corresponding dimension of the gradient box. Negative values are invalid.

<linear-color-stop>

A color-stop's <color> value, followed by an one or two optional stop positions (either a <percentage> or a <length> along the gradient's axis). A percentage of 0%, or a length of 0, represents the center of the gradient; the value 100% represents the intersection of the ending shape with the virtual gradient ray. Percentage values in between are linearly positioned on the gradient ray. Including two stop positions is equivalent to declaring two color stops with the same color at the two positions.

<color-hint>

Th color-hint is an interpolation hint defining how the gradient progresses between adjacent color stops. The length defines at which point between two color stops the gradient color should reach the midpoint of the color transition. If omitted, the midpoint of the color transition is the midpoint between two color stops.

Description

As with any gradient, a radial gradient has no intrinsic dimensions; i.e., it has no natural or preferred size, nor a preferred ratio. Its concrete size will match the size of the element it applies to.

To create a radial gradient that repeats so as to fill its container, use the repeating-radial-gradient() function instead.

Because <gradient>s belong to the <image> data type, they can only be used where <image>s can be used. For this reason, radial-gradient() won't work on background-color and other properties that use the <color> data type.

Composition of a radial gradient

A radial gradient is defined by a center point, an ending shape, and two or more color-stop points.

To create a smooth gradient, the radial-gradient() function draws a series of concentric shapes radiating out from the center to the ending shape (and potentially beyond). The ending shape may be either a circle or an ellipse.

Color-stop points are positioned on a virtual gradient ray that extends horizontally from the center towards the right. Percentage-based color-stop positions are relative to the intersection between the ending shape and this gradient ray, which represents 100%. Each shape is a single color determined by the color on the gradient ray it intersects.

Examples

Simple gradient

<div class="radial-gradient"></div>

.radial-gradient {
  width: 240px;
  height: 120px;
}

.radial-gradient {
  background-image: radial-gradient(cyan 0%, transparent 20%, salmon 40%);
} 

Non-centered gradient

<div class="radial-gradient"></div>

.radial-gradient {
  width: 240px;
  height: 120px;
}

.radial-gradient {
  background-image: radial-gradient(farthest-corner at 40px 40px,
      #f35 0%, #43e 100%);
}

More radial-gradient examples

Please see Using CSS gradients for more examples.

Specifications

Specification	Status	Comment
CSS Images Module Level 3 The definition of 'radial-gradients()' in that specification.	Candidate Recommendation	Initial definition.

Browser compatibility

BCD tables only load in the browser

Quantum CSS notes

Gecko used to have a long-standing bug whereby radial gradients like radial-gradient(circle gold,red) would work, even though they shouldn't because of the missing comma between circle and gold. Also, calc() expressions were rejected — causing the value to be invalid — when used as the radius component of a radial-gradient() function (bug 1376019). Firefox's new parallel CSS engine (also known as Quantum CSS or Stylo, released in Firefox 57) fixed these bugs.

See also

• Using CSS gradients
• Other gradient functions: repeating-radial-gradient(), linear-gradient(), repeating-linear-gradient(), conic-gradient(), repeating-conic-gradient()
• <image>
• image()
• element()()
• image-set()
• cross-fade()