movedY()
A Number system variable that tracks the mouse's vertical movement.
movedY tracks how many pixels the mouse moves up or down between frames. movedY will have a negative value if the mouse moves up between frames and a positive value if it moves down. movedY can be calculated as mouseY - pmouseY.
Examples

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