reference / pictures
pixel
The color of one pixel of a picture or canvas, counting from the top left: pixel photo at 10 20. A place outside the picture is clear black. Reading a canvas copies it back from the graphics card first, which stalls the frame, so do it once and keep the answer.
photo = load "landscape.png"image photo at 20 20c = pixel photo at 100 40no strokefill crect at 20 200 size 120 60fill (pixel photo at 100 100)rect at 160 200 size 120 60
How to write it
pixel picture at number number
Gives a color.