sdk/fidl/fuchsia.ui.input3/modifiers.fidl

// Copyright 2020 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.ui.input3;

/// Modifiers are special keys that modify the purpose or the function
/// of other keys when used in combination with them.  In the Modifiers type,
/// a bit is set if the specific modifier key is actuated (held down),
/// irrespective of whether the modifier is has an associated lock state or not.
type Modifiers = flexible bits : uint64 {
    /// Applies when the `CAPS_LOCK` modifier is actuated.
    CAPS_LOCK = 0x00000001;
    /// Applies when the `NUM_LOCK` modifier is actuated.
    NUM_LOCK = 0x00000002;
    /// Applies when the `SCROLL_LOCK` modifier is actuated.
    SCROLL_LOCK = 0x00000004;

    // TODO: Define additional modifiers as needed.
    // SHIFT, CONTROL, ALT, META
    // ALT_GRAPH, FUNCTION, FUNCTION_LOCK, SYMBOL, SYMBOL_LOCK
};

/// Lock state reports whether the lock is active for the keys which have a lock
/// state (need to be pressed once to activate, and one more time to deactivate).
/// A set bit denotes active lock state.
type LockState = flexible bits : uint64 {
    /// Applies when the `CAPS_LOCK` modifier is locked.
    ///
    /// Users should bear in mind that the effect of `CAPS_LOCK` is limited to
    /// alphabetic keys (not even *alphanumerics*) mainly.
    ///
    /// For example, pressing `a` on a US QWERTY keyboard while `CAPS_LOCK`
    /// state is locked results in the key meaning `A`, just as if the Shift modifier
    /// was used.  However, pressing `[` when `CAPS_LOCK` is locked gives `[`,
    /// even though Shift+`[` gives `{`.
    ///
    /// The position of alphabetic keys may vary depending on the keymap in
    /// current use too.
    CAPS_LOCK = 0x00000001;
    /// Applies when the `NUM_LOCK` modifier is locked.
    NUM_LOCK = 0x00000002;
    /// Applies when the `SCROLL_LOCK` modifier is locked.
    SCROLL_LOCK = 0x00000004;
};