MobTouch (mob_touch v0.1.0)

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Stream the user's raw screen touches to a screen — a Mob plugin.

Unlike per-widget on_tap (which only fires for a tapped button), this observes every touch on the app's surface and reports its coordinates, so you can build drawing, custom gestures, heatmaps, joysticks, and the like.

It observes without consuming: the touches still reach the app's normal UI, so buttons and scrolling keep working while you stream. No runtime permission.

Updates arrive in the screen's handle_info/2:

handle_info({:touch, %{phase: phase, x: x, y: y, pointer: pointer,
                       timestamp: ms}}, socket)
  • phase — :down (finger lands), :move, :up (finger lifts), or :cancel (the OS took the gesture, e.g. a system swipe).
  • x, y — dp (logical pixels), origin top-left of the app window; the same coordinate space the layout uses.
  • pointer — a stable id per finger across a gesture, so multi-touch is distinguishable. Single-finger use can ignore it.
  • timestamp — unix milliseconds.

iOS: a passive UIGestureRecognizer on the key window. Android: a Window.Callback that observes dispatchTouchEvent and forwards it on.

Call stop/1 when you no longer need the stream — the observer stays installed (and keeps the screen's mailbox busy on every touch) until you do.

Summary

Functions

start(socket, opts \\ [])

Start streaming touches to the calling screen.

stop(socket)

Stop streaming touches and remove the observer.

Functions

start(socket, opts \\ [])

@spec start(
  Mob.Socket.t(),
  keyword()
) :: Mob.Socket.t()

Start streaming touches to the calling screen.

Options:

  • :throttle_ms — the minimum interval between :move deliveries (default 16, ≈ 60 Hz). :down/:up/:cancel are never throttled. Raise it to cut mailbox traffic for coarse gestures; set 0 for every raw move.

stop(socket)

@spec stop(Mob.Socket.t()) :: Mob.Socket.t()

Stop streaming touches and remove the observer.