rectMode()
Modifies the location from which rectangles are drawn by changing the way in which parameters given to rect() are interpreted.
The default mode is rectMode(CORNER), which interprets the first two parameters of rect() as the upper-left corner of the shape, while the third and fourth parameters are its width and height.
rectMode(CORNERS) interprets the first two parameters of rect() as the location of one corner, and the third and fourth parameters as the location of the opposite corner.
rectMode(CENTER) interprets the first two parameters of rect() as the shape's center point, while the third and fourth parameters are its width and height.
rectMode(RADIUS) also uses the first two parameters of rect() as the shape's center point, but uses the third and fourth parameters to specify half of the shape's width and height.
The parameter must be written in ALL CAPS because Lua is a case-sensitive language.
Examples

function setup()
size(400, 400)
rectMode(CORNER) -- Default rectMode is CORNER
fill(255) -- Set fill to white
rect(100, 100, 200, 200) -- Draw white rect using CORNER mode
rectMode(CORNERS) -- Set rectMode to CORNERS
fill(100) -- Set fill to gray
rect(100, 100, 200, 200) -- Draw gray rect using CORNERS mode
describe('White square drawn in center with overlaid gray square in upper left corner')
end

function setup()
size(400, 400)
rectMode(RADIUS) -- Set rectMode to RADIUS
fill(255) -- Set fill to white
rect(200, 200, 120, 120) -- Draw white rect using RADIUS mode
rectMode(CENTER) -- Set rectMode to CENTER
fill(100) -- Set fill to gray
rect(200, 200, 120, 120) -- Draw gray rect using CENTER mode
describe('A centered white square surrounding a smaller centered gray square')
end
Syntax
rectMode(mode)
Parameters
| Parameter | |
|---|---|
| mode | Constant: either CENTER, RADIUS, CORNER or CORNERS |