zircon/system/fidl/fuchsia-hardware-backlight/backlight.fidl

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

library fuchsia.hardware.backlight;
using zx;

struct State {
    bool backlight_on;
    /// |brightness| can either be:
    /// 1. The unitless brightness value on a linear scale where 0.0 is the minimum
    ///    brightness and 1.0 is the maximum brightness - represents the current /
    ///    desired brightness as a percentage within the supported range. Used
    ///    by the |GetStateNormalized| / |SetStateNormalized| calls.
    /// 2. Absolute brightness in nits. Used by the |GetStateAbsolute| /
    ///    |SetStateAbsolute| calls.
    float64 brightness;
};

protocol Device {
    /// Gets the current backlight brightness as a percentage value between 0.0
    /// and 1.0
    GetStateNormalized() -> (State state) error zx.status;

    /// Sets the current backlight brightness as a percentage value between 0.0
    /// and 1.0
    SetStateNormalized(State state) -> () error zx.status;

    /// Gets the current backlight brightness in nits
    GetStateAbsolute() -> (State state) error zx.status;

    /// Sets the current backlight brightness in nits
    SetStateAbsolute(State state) -> () error zx.status;

    /// Gets the maximum supported backlight brightness in nits, if known.
    /// Otherwise returns error ZX_ERR_NOT_SUPPORTED.
    GetMaxAbsoluteBrightness() -> (float64 max_brightness) error zx.status;
};