movedX
A Number system variable that tracks the mouse's horizontal movement.
movedX tracks how many pixels the mouse moves left or right between frames. movedX will have a negative value if the mouse moves left between frames and a positive value if it moves right. movedX can be calculated as mouseX - pmouseX.
Examples

function setup()
size(100, 100)
describe(
'A gray square. The text ">>" appears when the user moves the mouse to the right. The text "<<" appears when the user moves the mouse to the left.'
)
end
function draw()
background(200)
fill(0)
-- Style the text.
textAlign(CENTER)
textSize(16)
-- Display >> when movedX is positive and
-- << when it's negative.
if movedX > 0 then
text('>>', 50, 50)
elseif movedX < 0 then
text('<<', 50, 50)
end
end
Syntax
movedX
Returns
Number: positive or negative number tracking horizontal movement.