Mouse Jitter Filter Lua Script

-- rebind: min_sdk=0.1.0 mouse_block=true
-- rebind: name=Mouse Jitter Filter
-- rebind: description=Reduce mouse tremor and jitter while preserving intentional movement

local cfg = UI.Schema({
    enabled = UI.Toggle(true, { label = "Enable Filter" }),
    
    jitter_threshold = UI.Slider(2, {
        min = 1,
        max = 10,
        suffix = "px",
        label = "Jitter Threshold",
        tooltip = "Movements smaller than this are filtered out",
        group = "Filtering",
    }),
    
    smoothing = UI.Slider(40, {
        min = 0,
        max = 90,
        suffix = "%",
        label = "Smoothing",
        tooltip = "Higher = smoother but more latency",
        group = "Filtering",
    }),
    
    acceleration_factor = UI.Slider(1.2, {
        min = 1.0,
        max = 3.0,
        step = 0.1,
        label = "Acceleration Factor",
        tooltip = "Boost large movements to maintain responsiveness",
        group = "Advanced",
    }),
})

local buffer = { x = 0, y = 0 }
local lastMagnitude = 0
local frameCounter = 0

function OnMove(dx, dy)
    if not cfg.enabled then
        return true
    end

    -- calculate movement magnitude
    local magnitude = math.sqrt(dx * dx + dy * dy)

    -- filter out sub-threshold jitter
    if magnitude < cfg.jitter_threshold then
        return false
    end

    -- apply exponential smoothing
    local smoothFactor = cfg.smoothing / 100
    buffer.x = buffer.x * smoothFactor + dx * (1 - smoothFactor)
    buffer.y = buffer.y * smoothFactor + dy * (1 - smoothFactor)

    -- apply acceleration boost for large movements to maintain responsiveness
    local accelFactor = 1.0
    if magnitude > cfg.jitter_threshold * 3 then
        accelFactor = cfg.acceleration_factor
    end

    local outX = buffer.x * accelFactor
    local outY = buffer.y * accelFactor

    -- send smoothed movement
    HID.Move(outX, outY)
    lastMagnitude = magnitude
    frameCounter = frameCounter + 1

    return false
end

function OnBlur()
    -- reset buffers when leaving the active window
    buffer.x = 0
    buffer.y = 0
    lastMagnitude = 0
    frameCounter = 0
end

function OnStop()
    Audio.StopAll()
end