only ever supported by Sprite and BitmapText. Handle it globally, using
m_size. This way, an actor only needs to set m_size to support alignment.
This means alignment can be set for non-drawing ActorFrames, if a size
is set explicitly. This allows stretching from the border of a frame
without playing games with extra nested frames. "setsize,100,100;valign,4;zoomx,.5"
This adds an extra matrix multiply. This will only happen for actors
actually set to non-centered alignment, which is the exception.
BitmapText still overrides this behavior a bit. Alignment for text
does two things: changes the alignment of the bounding box vs. the
X/Y position (the generic behavior), and changes the alignment of
the text within the bounding box.
yet decided whether these should be -1.0 ... +1.0, indicating
"fully left aligned" and "fully right aligned", or 0.0 ... 1.0,
indicating "anchor to this fractional position in m_size".
It may become the latter.)
Glenn Maynard