keySplines - SVG: Scalable Vector Graphics 编辑

The keySplines attribute defines a set of Bézier curve control points associated with the keyTimes list, defining a cubic Bézier function that controls interval pacing.

This attribute is ignored unless the calcMode attribute is set to spline.

If there are any errors in the keySplines specification (bad values, too many or too few values), the animation will not occur.

Four elements are using this attribute: <animate>, <animateColor>, <animateMotion>, and <animateTransform>

html, body, svg {
  height: 100%;
}

<svg viewBox="0 0 120 120" xmlns="http://www.w3.org/2000/svg">
  <circle cx="60" cy="10" r="10">
    <animate attributeName="cx" dur="4s" calcMode="spline" repeatCount="indefinite"
        values="60 ; 110 ; 60 ; 10 ; 60" keyTimes="0 ; 0.25 ; 0.5 ; 0.75 ; 1"
        keySplines="0.5 0 0.5 1 ; 0.5 0 0.5 1 ; 0.5 0 0.5 1 ; 0.5 0 0.5 1"/>
    <animate attributeName="cy" dur="4s" calcMode="spline" repeatCount="indefinite"
        values="10 ; 60 ; 110 ; 60 ; 10" keyTimes="0 ; 0.25 ; 0.5 ; 0.75 ; 1"
        keySplines="0.5 0 0.5 1 ; 0.5 0 0.5 1 ; 0.5 0 0.5 1 ; 0.5 0 0.5 1"/>
  </circle>
</svg>

Usage notes

The attribute value is a semicolon-separated list of control point descriptions.

<control-point>

Each control point description is a set of four values: x1 y1 x2 y2, describing the Bézier control points for one time segment. The keyTimes values that define the associated segment are the Bézier "anchor points", and the keySplines values are the control points. Thus, there must be one fewer sets of control points than there are keyTimes.

The values of x1 y1 x2 y2 must all be in the range 0 to 1.

Specifications

See also

• Wikipedia article on Bézier curves