SVG animation with SMIL

Firefox 4 introduced support for animating SVG using Synchronized Multimedia Integration Language (SMIL). SMIL allows you to:

• animate the numeric attributes of an element (x, y, ...)
• animate transform attributes (translation or rotation)
• animate color attributes
• follow a motion path

This is done adding an SVG element like <animate> inside the SVG element to animate. Below are examples for the four different ways.

Animating attributes of an element

The following example animates the cx attribute of a circle. To do so, we add an <animate> element inside the <circle> element. The important attributes for <animate> are:

attributeName

The name of the attribute to animate.

from

The initial value of the attribute.

to

The final value.

dur

The duration of the animation (for example, write '5s' for 5 seconds).

If you want to animate more attributes inside the same element, just add more <animate> elements.

<svg width="300" height="100">
  <title>Attribute Animation with SMIL</title>
  <rect x="0" y="0" width="300" height="100" stroke="black" stroke-width="1" />
  <circle cx="0" cy="50" r="15" fill="blue" stroke="black" stroke-width="1">
    <animate
       attributeName="cx" from="0" to="500"
       dur="5s" repeatCount="indefinite" />
  </circle>
</svg>

Animating the transform attributes

The <animateTransform> element let you animate transform attributes. This new element is necessary because we are not animating a simple attribute like x which is just a number. Rotation attributes look like this: rotation(theta, x, y), where theta is the angle in degrees, and x and y are absolute positions. In the example below, we animate the center of the rotation and the angle.

<svg width="300" height="100">
  <title>SVG SMIL Animate with transform</title>
  <rect x="0" y="0" width="300" height="100" stroke="black" stroke-width="1" />
  <rect x="0" y="50" width="15" height="34" fill="blue" stroke="black" stroke-width="1">
    <animateTransform
       attributeName="transform"
       begin="0s"
       dur="20s"
       type="rotate"
       from="0 60 60"
       to="360 100 60"
       repeatCount="indefinite"
			/>
  </rect>
</svg>

Animation following a path

The <animateMotion> element lets you animate an element position and rotation according to a path. The path is defined the same way as in <path>. You can set the attribute to define whether the object rotates following the tangent of the path.

Example 1: Linear motion

In this example, a blue circle bounces between the left and right edges of a black box, over and over again, indefinitely. The animation here is handled by the <animateMotion> element. In this case, we're establishing a path consisting of a MoveTo command to establish the starting point for the animation, then the Horizontal-line command to move the circle 300 pixels to the right, followed by the Z command, which closes the path, establishing a loop back to the beginning. By setting the value of the repeatCount attribute to indefinite, we indicate that the animation should loop forever, as long as the SVG image exists.

<svg xmlns="http://www.w3.org/2000/svg" width="300" height="100">
  <title>SVG SMIL Animate with Path</title>
  <rect x="0" y="0" width="300" height="100" stroke="black" stroke-width="1" />
  <circle cx="0" cy="50" r="15" fill="blue" stroke="black" stroke-width="1">
    <animateMotion
       path="M 0 0 H 300 Z"
       dur="3s" repeatCount="indefinite" />
  </circle>
</svg>

View live sample

Example 2: Curved motion

Same example as before with a curved path and following the direction of the path.

<svg width="300" height="100">
  <title>SVG SMIL Animate with Path</title>
  <rect x="0" y="0" width="300" height="100" stroke="black" stroke-width="1" />
  <rect x="0" y="0" width="20" height="20" fill="blue" stroke="black" stroke-width="1">
    <animateMotion
       path="M 250,80 H 50 Q 30,80 30,50 Q 30,20 50,20 H 250 Q 280,20,280,50 Q 280,80,250,80Z"
       dur="3s" repeatCount="indefinite" rotate="auto" />
  </rect>
</svg>

See also

• SVG
• SVG Animation Specification
• SMIL Specification