Question

Here is what I read about it but cant understand exactly what it does:

One way to implement rubber-banding is to draw in XOR mode. You set
XOR mode by calling the setXORMode() method for a graphics context and
passing a color to it — usually the background color. In this mode
the pixels are not written directly to the screen. The color in which
you are drawing is combined with the color of the pixel currently
displayed together with a third color that you specify, by exclusive
ORing them together, and the resultant pixel color is written to the
screen. The third color is usually set to be the background color, so
the color of the pixel that is written is the result of the following
operation:

resultant_Color = foreground_color^background_color^current_color

I know how XORing works but don’t know what the above paragraph means. Please elucidate it for me

Answer 1

It takes a color in and applies an XOR mask just like a regular XOR would a bit mask, except it is on the RGB colors, so it produces the color you pass in if it overlays a color with the same values or the inverse of that colors RGB and and color below its RGB if the values are different.

Just write some code and try it and it will be immediate evident what happens.