MacPaint had that in 1983, but it never shipped because Bill Atkinson “was afraid that if he left it in, people would actually use it a lot, and MacPaint would be regarded as an inadequate word processor instead of a great drawing program” (https://www.folklore.org/MacPaint_Evolution.html)

Also shows a way to do that fast:

“ First, he wrote assembly language routines to isolate the bounding box of each character in the selected range. Then he computed a checksum of the pixels within each bounding box, and compared them to a pre-computed table that was made for each known font, only having to perform the full, detailed comparison if the checksum matched.”