pebble/src/fw/applib/compass_service.h
2025-01-27 11:38:16 -08:00

85 lines
3.4 KiB
C

/*
* Copyright 2024 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <stdbool.h>
#include <stdint.h>
#include "drivers/mag.h"
#include "services/common/ecompass.h"
//! @addtogroup Foundation
//! @{
//! @addtogroup EventService
//! @{
//! @addtogroup CompassService
//!
//! \brief The Compass Service combines information from Pebble's accelerometer and
//! magnetometer to automatically calibrate
//! the compass and transform the raw magnetic field information into a \ref CompassHeading,
//! that is an angle to north. It also
//! provides magnetic north and information about its status and accuracy through the \ref
//! CompassHeadingData structure. The API is designed to also provide true north in a future
//! release.
//!
//! Note that not all platforms have compasses. To check for the presence of a compass at
//! compile time for the current platform use the `PBL_COMPASS` define.
//!
//! To learn more about the Compass Service and how to use it, read the
//! <a href="https://developer.getpebble.com/guides/pebble-apps/sensors/magnetometer/">
//! Determining Direction</a> guide.
//!
//! For available code samples, see the
//! <a href="https://github.com/pebble-examples/feature-compass">feature-compass</a> example.
//!
//! @{
//! Peek at the last recorded reading.
//! @param[out] data a pointer to a pre-allocated CompassHeadingData
//! @return Always returns 0 to indicate success.
int compass_service_peek(CompassHeadingData *data);
//! Set the minimum angular change required to generate new compass heading events.
//! The angular distance is measured relative to the last delivered heading event.
//! Use 0 to be notified of all movements.
//! Negative values and values > TRIG_MAX_ANGLE / 2 are not valid.
//! The default value of this property is TRIG_MAX_ANGLE / 360.
//! @return 0, success.
//! @return Non-Zero, if filter is invalid.
//! @see compass_service_subscribe
int compass_service_set_heading_filter(CompassHeading filter);
//! Callback type for compass heading events
//! @param heading copy of last recorded heading
typedef void (*CompassHeadingHandler)(CompassHeadingData heading);
//! Subscribe to the compass heading event service. Once subscribed, the handler
//! gets called every time the angular distance relative to the previous value
//! exceeds the configured filter.
//! @param handler A callback to be executed on heading events
//! @see compass_service_set_heading_filter
//! @see compass_service_unsubscribe
void compass_service_subscribe(CompassHeadingHandler handler);
//! Unsubscribe from the compass heading event service. Once unsubscribed,
//! the previously registered handler will no longer be called.
//! @see compass_service_subscribe
void compass_service_unsubscribe(void);
//! @} // end addtogroup CompassService
//! @} // end addtogroup EventService
//! @} // end addtogroup Foundation