size of "images" created by imagestring

imagestring essentially turns text strings into images. Unfortunately,
these images can be of any size and, as far as I know, an images size
needs to be decided upon before imagestring is called.

So is there anyway the size that imagestring would require could be
calculated before the image was created?

When TTF fonts are used, the imagettfbbox function can be used to do
this, but what if TTF fonts aren't being used?

yawnmoth wrote:Try using the GD library -- much more powerful.

Carl Vondrick wrote:Correct me if I'm wrong, but wouldn't I have to specify a font if I
were to use the GD library?

Or is there a way for me to convert text strings to images while using
some of the built-in fonts that already exist (such as those that
imagestring uses?)