joystick_gremlin_axis_to_scrollwheel/axis_to_scrollwheel.py

from datetime import datetime, timedelta
import gremlin
from gremlin.user_plugin import *

# User-configurable variables; these appear in the Joystick Gremlin UI

axis = PhysicalInputVariable(
  "Axis",
  "The axis that will trigger scrolling.",
  [gremlin.common.InputType.JoystickAxis],
)

mode = ModeVariable(
  "Mode",
  "The mode in which the axis will be mapped.",
)

scroll_speed = FloatVariable(
  "Scroll Speed",
  "Adjusts the rate at which the target button is pressed, relative to the axis strength.",
  1.0,
)

deadzone = FloatVariable(
  "Deadzone",
  "Applies a deadzone to both sides of the axis.",
  0.0,
)

# NB: Not a real boolean; invert.value returns 0 or 2
invert = BoolVariable(
  "Invert",
  "Reverse the direction that the axis scrolls.",
  False,
)

# Constants
AXIS_SCALING_FACTOR = 250 # Value determined through testing.

# Debugging
ticks = 0

axis_decorator = axis.create_decorator(mode.value)
last_timestamp = datetime.now()
scroll_scaling = scroll_speed.value if scroll_speed.value != 0.0 else 1.0

# TODO: use this code instead when periodic callback is fixed
# @gremlin.input_devices.periodic(1)
@axis_decorator.axis(axis.input_id)
def handle_axis(event):
  global last_timestamp
  global damping
  global ticks # debug

  # TODO: use this code instead when periodic callback is fixed
  # axis_value = joy[axis.device_guid].axis(axis.input_id).value
  axis_value = event.value

  if (abs(axis_value) < deadzone.value):
    return

  delta = (datetime.now() - last_timestamp) / timedelta(milliseconds=1)

  # Scroll speed is *inversely proportional* to the right-hand side of this comparison
  if delta >= ((1 - abs(axis_value)) * AXIS_SCALING_FACTOR) / scroll_scaling:
    direction = 1 if axis_value > 0 else -1
    if invert.value: direction = direction * -1
    gremlin.sendinput.mouse_wheel(direction)
    last_timestamp = datetime.now()

    # debug
    ticks += 1
    gremlin.util.log(ticks)