Units
Percentages as units are tested with animated ellipses compared to local and px units.
Because the viewBox is set to a width of 400 and a height of 300, a horizontal length of
400 corresponds to 100% and a vertical length of 300 corresponds to 100%.
The attributes rx and ry as well as cx and cy are related to these lengths.
Values with different units can be converted
into the same unit system before a continuous animation can take place - or an
interpolated presentation value is a combination of values of different units,
that have to be converted into one value in device pixels to be presented.
For the blue ellipse the values of the animation list is given in gray for comparison,
for the dark blue ellipse there is a red comparison below with an animation, using
only px as units, no mix of different units.
If something red gets visible, an error is occured.