Animation of tref
Animation of specific attributes of the tref element.
The tref attribute textLength changes from 400 to 600 in 5s
with textLength explicitely set to 1000 for the text element.
The light grey and grey rectangles show the corresponding scaling
and the grey stroked text the approximate glyph positions using an
animation of the x attribute of text.
CDEF
abCDEFgh
abgh