sdk/fidl/fuchsia.input.report/touch.fidl

// Copyright 2019 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.input.report;

/// A hardcoded number of max contacts per report. This should be increased in the future if
/// we see devices with more than the max amount.
const uint32 TOUCH_MAX_CONTACTS = 10;
const uint32 TOUCH_MAX_NUM_BUTTONS = 10;

/// The device type from which the touch originated.
enum TouchType : uint32 {
    /// A touch screen has direct finger input associated with a display.
    TOUCHSCREEN = 1;
    /// A touch pad is a pointer device that tracks finger positions.
    TOUCHPAD = 2;
};

/// `ContactInputDescriptor` describes the fields associated with a touch on a touch device.
table ContactInputDescriptor {
    /// Describes the reporting of the x-axis.
    1: Axis position_x;

    /// Describes the reporting of the y-axis.
    2: Axis position_y;

    /// Pressure of the contact.
    3: Axis pressure;

    /// Width of the area of contact.
    4: Axis contact_width;

    /// Height of the area of contact.
    5: Axis contact_height;
};

/// Describes the format of the input report that will be sent from the keyboard
/// to the device.
table TouchInputDescriptor {
    /// The contact descriptors associated with this touch descriptor.
    1: vector<ContactInputDescriptor>:TOUCH_MAX_CONTACTS contacts;

    /// The max number of contacts that this touch device can report at once.
    2: uint32 max_contacts;

    /// The type of touch device being used.
    3: TouchType touch_type;

    /// Identifiers for the physical buttons on a touch device.
    4: vector<uint8>:TOUCH_MAX_NUM_BUTTONS buttons;
};

/// The capabilities of a touch device.
table TouchDescriptor {
    1: TouchInputDescriptor input;
};

/// `ContactInputReport` describes one touch on a touch device.
table ContactInputReport {
    /// Identifier for this contact.
    1: uint32 contact_id;

    /// A contact's position on the x axis.
    2: int64 position_x;

    /// A contact's position on the y axis.
    3: int64 position_y;

    /// Pressure of the contact.
    4: int64 pressure;

    /// Width of the bounding box around the touch contact. Combined with
    /// `contact_height`, this describes the area of the touch contact.
    /// `contact_width` and `contact_height` should both have units of distance,
    /// and they should be in the same units as `position_x` and `position_y`.
    5: int64 contact_width;

    /// Height of the bounding box around the touch contact. Combined with
    /// `contact_width`, this describes the area of the touch contact.
    /// `contact_width` and `contact_height` should both have units of distance,
    /// and they should be in the same units as `position_x` and `position_y`.
    6: int64 contact_height;
};

/// `TouchInputReport` describes the current contacts recorded by the touchscreen.
table TouchInputReport {
    /// The contacts currently being reported by the device.
    1: vector<ContactInputReport>:TOUCH_MAX_CONTACTS contacts;

    /// Identifiers for currently pressed buttons.
    2: vector<uint8>:TOUCH_MAX_NUM_BUTTONS pressed_buttons;
};