r - SVG: Scalable Vector Graphics 编辑

The r attribute defines the radius of a circle.

Two elements are using this attribute: <circle>, and <radialGradient>

html,body,svg { height:100% }

<svg viewBox="0 0 300 200" xmlns="http://www.w3.org/2000/svg">
  <radialGradient r="0" id="myGradient000">
    <stop offset="0"    stop-color="white" />
    <stop offset="100%" stop-color="black" />
  </radialGradient>
  <radialGradient r="50%" id="myGradient050">
    <stop offset="0"    stop-color="white" />
    <stop offset="100%" stop-color="black" />
  </radialGradient>
  <radialGradient r="100%" id="myGradient100">
    <stop offset="0"    stop-color="white" />
    <stop offset="100%" stop-color="black" />
  </radialGradient>

  <circle cx="50"  cy="50" r="0"/>
  <circle cx="150" cy="50" r="25"/>
  <circle cx="250" cy="50" r="50"/>

  <rect x="20"  y="120" width="60" height="60" fill="url(#myGradient000)" />
  <rect x="120" y="120" width="60" height="60" fill="url(#myGradient050)" />
  <rect x="220" y="120" width="60" height="60" fill="url(#myGradient100)" />
</svg>

circle

For <circle>, r defines the radius of the circle and therefor its size. With a value lower or equal to zero the circle won't be drawn at all.

Note: Starting with SVG2, r is a Geometry Property meaning this attribute can also be used as a CSS property for circles.

radialGradient

For <radialGradient>, r defines the radius of the end circle for the radial gradient.

The gradient will be drawn such that the 100% gradient stop is mapped to the perimeter of this end circle. A value of lower or equal to zero will cause the area to be painted as a single color using the color and opacity of the last gradient <stop>.

Specifications