love.graphics.setScissor
Sets or disables scissor.

The scissor limits the drawing area to a specified rectangle. This affects all graphics calls, including love.graphics.clear.

The dimensions of the scissor is unaffected by graphical transformations (translate, scale, ...).
love.graphics.setScissor( x, y, width, height )
x number x coordinate of upper left corner.
y number y coordinate of upper left corner.
width number width of clipping rectangle.
height number height of clipping rectangle.
love.graphics.setScissor()