hello, perhaps silly question but i struggle with it as beginner.

i want to create rectangle using mouse coordinates. so desired behviour would be like this:

mouse pressed -> set starting position of upper-left corner of rect...
mouse dragged -> setting end position of rectangle (lower-right corner)
mouse released -> end of drawing the rect.

so pretty much the same as 'selection tool' in many graphic applications.

how can i program this in processing?
rect() function allow me to create rectangles only based on predefined coordinates...

thanks for help.