I'm trying to print text rotated, so it's readable if you rotate the watch a quarter-turn counter-clockwise.

I checked the font API but couldn't find out how to do this.

Do I need to make a separate .png for each number, separately? Or is there an easier way?

Thanks for the help!

You could try rotating the font, setting PWTS_WRAP on your PWidgetTextDynamic, and setting left/right of the PWTextBox so that its width is less than the height of two lines of the font.
There should be some program that can batch rotate a font but I'm not sure which. FontForge probably can with a bit of Python scripting.
Not sure if this is really easier than PNG per character, especially if you don't need many different characters (e.g. just numbers).