MOUSE

Enable the software mouse cursor, choose its icon, and install pointer event handlers. Coordinates are HDMI screen pixels with (0,0) at the top-left, the same space MM.INFO$ and PAINT use.

MOUSE ON MOUSE OFF MOUSE CURSOR [type]

type - pointer (default), hand, crosshair, questionmark, deny, hidden, or

0..5 in that order.

MOUSE ON draws a cursor at the current pointer position while a program runs. MOUSE OFF hides it. The cursor is composited over the finished frame and never writes to a PAGE buffer, so moving the pointer cannot change page pixels or interrupt drawing across multiple pages.

Use MOUSE CURSOR hidden (type 5) to keep reading the pointer position and buttons – MOUSE(x), MOUSE(y) and the ON MOUSEMOVE / ON MOUSECLICK / ON MOUSEDOWN / ON MOUSEUP handlers all keep working – while no cursor sprite is drawn. This lets a program draw its own pointer, or none at all.

Pointer events call SUB handlers installed with ON:

ON MOUSECLICK handler
ON MOUSEDOWN handler
ON MOUSEUP handler
ON MOUSEMOVE handler

ON MOUSEDOWN is an alias of ON MOUSECLICK: both fire on a button press. ON MOUSEUP fires when the button is released. Press and release handlers receive the screen position and button:

SUB click(x, y, button$)
  PRINT x, y, button$      ' button$ is "left", "middle" or "right"
END SUB

The move handler receives the new position:

SUB move(x, y)
  PRINT x, y
END SUB

Example:

MOUSE ON
MOUSE CURSOR crosshair
ON MOUSEMOVE move
ON MOUSECLICK click
ON MOUSEUP release
DO
  PAUSE 10
LOOP

Source: docs/help/mouse.txt inmmcore. On the computer, typeHELP MOUSE.