Why does Tkinter wipe previous rectangles when drawing?
The default color for the outline of a rectangle is black. This makes it seem like the other rectangles aren't being drawn when their outline is just overlapping.
Try changing:
self.rect_array.append(c.create_rectangle(one_pixel_loc, fill='white'))to this:
self.rect_array.append(c.create_rectangle(one_pixel_loc, fill='white', outline='white')Not sure if this is exactly what you're looking for, hope it helps.