The test consists of two circles: an orange circle on the left,
which serves as a reference, and a blue circle on the right,
whose transform
attribute is animated. Animation of
the circles begins at t=1s and lasts for 3s.
The transform animation that applies to the blue circle is of type
"scale", and specifies by="1"
. Since the animation is
considered to be equivalent to one that specifies from="0" to="1"
,
when the animation begins the circle will be scaled down to a point,
and then will be scaled up until it reaches its original size at
t=4s.