Is it possible to feed an arbitrary (but valid) font file into eggPlant & have it render and detect text based on that font file?
You can do something like that using the Text Image Generation functionality. You can do that directly in eggPlant for Mac or as an external agent (either on the SUT or the eggPlant machine) on Windows. Those features work well but only if the Text is being rendered using those same font system on the SUT.
You can read more about that functionality in the online [u]Using Eggplant[/u] documentation.
Jonathan, what exactly do you mean by external agents? What would be some examples, and how would they communicate with eggPlant?
The Text Image Generator program for Windows that we offer on our Download Page is an example of an external agent. It communicates with eggPlant over TCP (Port 5899 by default).