easing

The easing namespace provides Robert Penner’s standard easing algorithms.

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Function Signature

All easing functions follow the standard signature:

easing.<function>(time: number, begin: number, change: number, duration: number) --> number

• time: Current elapsed progression time (0 .. duration).
• begin: Starting value.
• change: Total delta to change (target - begin).
• duration: Total duration of the transition.

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Available Easing Families

Linear

• easing.linear(t, b, c, d)

Curve Families

Each family provides 4 variations: _in, _out, _in_out, and _out_in:

Family	Variations
quad	easing.quad_in, quad_out, quad_in_out, quad_out_in
cubic	easing.cubic_in, cubic_out, cubic_in_out, cubic_out_in
quart	easing.quart_in, quart_out, quart_in_out, quart_out_in
quint	easing.quint_in, quint_out, quint_in_out, quint_out_in
sine	easing.sine_in, sine_out, sine_in_out, sine_out_in
expo	easing.expo_in, expo_out, expo_in_out, expo_out_in
circ	easing.circ_in, circ_out, circ_in_out, circ_out_in
elastic	easing.elastic_in, elastic_out, elastic_in_out, elastic_out_in
back	easing.back_in, back_out, back_in_out, back_out_in
bounce	easing.bounce_in, bounce_out, bounce_in_out, bounce_out_in

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Example: Smooth Menu Slide-in

local anim_start = 0
local anim_duration = 0.35 -- 350ms

client.add_callback("render", function()
    local elapsed = globals.realtime - anim_start
    local clamped_t = math.min(elapsed, anim_duration)

    -- Smoothly interpolate X coordinate from 0 to 200 using quintic out
    local current_x = easing.quint_out(clamped_t, 0, 200, anim_duration)

    render.rect(vector(current_x, 100), vector(current_x + 150, 200), color(20, 20, 20, 200))
end)