Is there a straightforward way to write text onto the image in landscape orientation? I see no parameters to Image.draw_string() that would do this out of the box.
Alternatively, is there correspondingly simple way to rotate an image (one could rotate, write text, then rotate back in order to maintain an upright display). Neither the sensor nor the image modules seem to offer rotation functions.
No not that I know of, the text was originally added for displaying the FPS. If you like you could submit a feature request on github for text rotation (much easier, faster to implement than the alternative)