Centering output-pane text

I'm using gp:draw-string to display text in an output-pane. I'd like  
to center it horizontally (or perhaps right-justify). In order to do  
that, it would be great if there were a function that returns the  
width of the string in pixels.

Question #1: Is there such a function?

I happen to be using a fixed-width font, which means I could  
presumably do a simple computation based on the number of characters,  
but I'd like a more general solution.

For some of my panes (this is a calendar with days that respond to  
clicks and weekly totals that don't), I could use something other than  
an output-pane, but even then I don't see what kind of pane provides  
for centered text.

Question #2: Are there panes that provide for displaying centered text?

Thanks! (LWM 5.1.1)

Laughing Water