PicoGraphics error with 1Bit pen

[dajames-mk1]

I have a breakout garden 1.12" mono OLED display connected to a Pi Pico. I tested it using the oled_128x128_demo.cpp example program.

I imagine that the expected output is a white screen with the string "PIRATES!" in black bouncing around. (It would be really nice to have a short video of the expected output so that we can check correct operation). What I actually got was "PIRATES!" in black bouncing around on a background of white dots on black -- not easy to read!

It turns out that the code

        graphics.set_pen(1);
        graphics.clear();

doesn't set all the pixels in the rectangle of the full display to white, but only one pixel in 16. I tried setting the pen to 15 and achieved a white background, which gives the display I expected.

Clearly setting a 1-bit pen value to 15 is a nonsense. There is an error somewhere in the rectangle fill code for PicoGraphics_Pen1Bit.

EDIT: Sorry, I've just reread the documentation page for Pico Graphics and see that your 1-bit pen is supposed to work this way(!) As that's the case I suggest that the example could be improved by setting the pen colour to 15 (as I did) as the text is very hard to discern against a dithered background.