tobii_research_streams.h File Reference

Functionality for eye tracker streams. More...

Go to the source code of this file.

Data Structures
struct	TobiiResearchGazeOrigin
struct	TobiiResearchPupilData
struct	TobiiResearchGazePoint
struct	TobiiResearchEyeData
struct	TobiiResearchGazeData
struct	TobiiResearchHMDPupilPosition
struct	TobiiResearchHMDGazeOrigin
struct	TobiiResearchHMDGazeDirection
struct	TobiiResearchHMDEyeData
struct	TobiiResearchHMDGazeData
struct	TobiiResearchTimeSynchronizationData
struct	TobiiResearchExternalSignalData
struct	TobiiResearchNotification
struct	TobiiResearchStreamErrorData
struct	TobiiResearchEyeImage
struct	TobiiResearchEyeImageGif

Typedefs
typedef void(*	tobii_research_gaze_data_callback) (TobiiResearchGazeData *gaze_data, void *user_data)
	Gaze data callback. More...
typedef void(*	tobii_research_hmd_gaze_data_callback) (TobiiResearchHMDGazeData *hmd_gaze_data, void *user_data)
	HMD gaze data callback. More...
typedef void(*	tobii_research_external_signal_data_callback) (TobiiResearchExternalSignalData *external_signal_data, void *user_data)
	External signal callback. More...
typedef void(*	tobii_research_time_synchronization_data_callback) (TobiiResearchTimeSynchronizationData *time_synchronization_data, void *user_data)
	Time synchronization callback. More...
typedef void(*	tobii_research_stream_error_callback) (TobiiResearchStreamErrorData *stream_error, void *user_data)
	Stream error callback. More...
typedef void(*	tobii_research_notification_callback) (TobiiResearchNotification *notification, void *user_data)
	Notification callback. More...
typedef void(*	tobii_research_eye_image_callback) (TobiiResearchEyeImage *frame, void *user_data)
	Eye image callback. More...
typedef void(*	tobii_research_eye_image_as_gif_callback) (TobiiResearchEyeImageGif *frame, void *user_data)
	Eye image gif callback. More...

Enumerations

Functions
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_subscribe_to_gaze_data (TobiiResearchEyeTracker *eyetracker, tobii_research_gaze_data_callback callback, void *user_data)
	Subscribes to gaze data for the eye tracker. More...
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_unsubscribe_from_gaze_data (TobiiResearchEyeTracker *eyetracker, tobii_research_gaze_data_callback callback)
	Unsubscribes from gaze data for the eye tracker. More...
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_subscribe_to_hmd_gaze_data (TobiiResearchEyeTracker *eyetracker, tobii_research_hmd_gaze_data_callback callback, void *user_data)
	Subscribes to gaze data for the eye tracker. More...
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_unsubscribe_from_hmd_gaze_data (TobiiResearchEyeTracker *eyetracker, tobii_research_hmd_gaze_data_callback callback)
	Unsubscribes from HMD gaze data for the eye tracker. More...
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_subscribe_to_external_signal_data (TobiiResearchEyeTracker *eyetracker, tobii_research_external_signal_data_callback callback, void *user_data)
	Subscribes to external signal data for the eye tracker. More...
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_unsubscribe_from_external_signal_data (TobiiResearchEyeTracker *eyetracker, tobii_research_external_signal_data_callback callback)
	Unsubscribes from external signal data for the eye tracker. More...
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_subscribe_to_time_synchronization_data (TobiiResearchEyeTracker *eyetracker, tobii_research_time_synchronization_data_callback callback, void *user_data)
	Subscribes to time synchronization data for the eye tracker. More...
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_unsubscribe_from_time_synchronization_data (TobiiResearchEyeTracker *eyetracker, tobii_research_time_synchronization_data_callback callback)
	Unsubscribes from time synchronization data for the eye tracker. More...
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_subscribe_to_stream_errors (TobiiResearchEyeTracker *eyetracker, tobii_research_stream_error_callback callback, void *user_data)
	Subscribes to stream errors for the eye tracker. More...
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_unsubscribe_from_stream_errors (TobiiResearchEyeTracker *eyetracker, tobii_research_stream_error_callback callback)
	Unsubscribes from stream errors for the eye tracker. More...
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_subscribe_to_notifications (TobiiResearchEyeTracker *eyetracker, tobii_research_notification_callback callback, void *user_data)
	Subscribes to notifications for the eye tracker. More...
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_unsubscribe_from_notifications (TobiiResearchEyeTracker *eyetracker, tobii_research_notification_callback callback)
	Unsubscribes from notifications for the eye tracker. More...
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_subscribe_to_eye_image (TobiiResearchEyeTracker *eyetracker, tobii_research_eye_image_callback callback, void *user_data)
	Subscribes to eye image for the eye tracker. More...
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_subscribe_to_eye_image_as_gif (TobiiResearchEyeTracker *eyetracker, tobii_research_eye_image_as_gif_callback callback, void *user_data)
	Subscribes to eye image for the eye tracker with the image delivered in gif format. More...
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_unsubscribe_from_eye_image (TobiiResearchEyeTracker *eyetracker, tobii_research_eye_image_callback callback)
	Unsubscribes from eye image for the eye tracker. More...
TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL	tobii_research_unsubscribe_from_eye_image_as_gif (TobiiResearchEyeTracker *eyetracker, tobii_research_eye_image_as_gif_callback callback)
	Unsubscribes from eye image for the eye tracker. More...

Detailed Description

Functionality for eye tracker streams.

Copyright

COPYRIGHT 2017 - PROPERTY OF TOBII AB

2017 TOBII AB - KARLSROVAGEN 2D, DANDERYD 182 53, SWEDEN - All Rights Reserved.

NOTICE: All information contained herein is, and remains, the property of Tobii AB and its suppliers, if any. The intellectual and technical concepts contained herein are proprietary to Tobii AB and its suppliers and may be covered by U.S.and Foreign Patents, patent applications, and are protected by trade secret or copyright law. Dissemination of this information or reproduction of this material is strictly forbidden unless prior written permission is obtained from Tobii AB.

Typedef Documentation

typedef void(* tobii_research_external_signal_data_callback) (TobiiResearchExternalSignalData *external_signal_data, void *user_data)

External signal callback.

Implement this and send as a parameter to tobii_research_subscribe_to_external_signal_data.

Parameters

external_signal_data	External signal data received from the eye tracker.
user_data	Caller specific data sent in with tobii_research_subscribe_to_external_signal_data.

typedef void(* tobii_research_eye_image_as_gif_callback) (TobiiResearchEyeImageGif *frame, void *user_data)

Eye image gif callback.

Implement this and send as a parameter to tobii_research_subscribe_to_eye_image_as_gif.

Parameters

frame	Eye image gif frame received from the eye tracker.
user_data	Caller specific data sent in with tobii_research_subscribe_to_eye_image_as_gif.

typedef void(* tobii_research_eye_image_callback) (TobiiResearchEyeImage *frame, void *user_data)

Eye image callback.

Implement this and send as a parameter to tobii_research_subscribe_to_eye_image.

Parameters

frame	Eye image frame received from the eye tracker.
user_data	Caller specific data sent in with tobii_research_subscribe_to_eye_image.

typedef void(* tobii_research_gaze_data_callback) (TobiiResearchGazeData *gaze_data, void *user_data)

Gaze data callback.

Implement this and send as a parameter to tobii_research_subscribe_to_gaze_data.

Parameters

gaze_data	Gaze data received from the eye tracker.
user_data	Caller specific data sent in with tobii_research_subscribe_to_gaze_data.

typedef void(* tobii_research_hmd_gaze_data_callback) (TobiiResearchHMDGazeData *hmd_gaze_data, void *user_data)

HMD gaze data callback.

Implement this and send as a parameter to tobii_research_subscribe_to_hmd_gaze_data.

Parameters

hmd_gaze_data	HMD gaze data received from the eye tracker.
user_data	Caller specific data sent in with tobii_research_subscribe_to_hmd_gaze_data.

typedef void(* tobii_research_notification_callback) (TobiiResearchNotification *notification, void *user_data)

Notification callback.

Implement this and send as a parameter to tobii_research_subscribe_to_notifications.

Parameters

notification	Notification received from the eye tracker.
user_data	Caller specific data sent in with tobii_research_subscribe_to_notifications.

typedef void(* tobii_research_stream_error_callback) (TobiiResearchStreamErrorData *stream_error, void *user_data)

Stream error callback.

Implement this and send as a parameter to tobii_research_subscribe_to_stream_errors.

Parameters

stream_error	TobiiResearchStreamErrorData object.
user_data	Caller specific data sent in with tobii_research_subscribe_to_stream_errors.

typedef void(* tobii_research_time_synchronization_data_callback) (TobiiResearchTimeSynchronizationData *time_synchronization_data, void *user_data)

Time synchronization callback.

Implement this and send as a parameter to tobii_research_subscribe_to_time_synchronization_data.

Parameters

gaze_data	Time synchronization data received from the eye tracker.
user_data	Caller specific data sent in with tobii_research_subscribe_to_time_synchronization_data.

Enumeration Type Documentation

enum TobiiResearchExternalSignalChangeType

Defines external signal change type.

Enumerator
TOBII_RESEARCH_EXTERNAL_SIGNAL_VALUE_CHANGED	Indicates that the value sent to the eye tracker has changed.
TOBII_RESEARCH_EXTERNAL_SIGNAL_INITIAL_VALUE	Indicates that the value is the initial value, and is received when starting a subscription.
TOBII_RESEARCH_EXTERNAL_SIGNAL_CONNECTION_RESTORED	Indicates that there has been a connection lost and now it is restored and the value is the current value.

enum TobiiResearchEyeImageType

Defines eye image type.

Enumerator
TOBII_RESEARCH_EYE_IMAGE_TYPE_FULL	Indicates that the eye tracker could not identify the eyes, and the image is the full image.
TOBII_RESEARCH_EYE_IMAGE_TYPE_CROPPED	Indicates that the image is cropped and shows the eyes.
TOBII_RESEARCH_EYE_IMAGE_TYPE_UNKNOWN	The eye image has an unexpected type.

enum TobiiResearchNotificationType

Defines notification types

Enumerator
TOBII_RESEARCH_NOTIFICATION_CONNECTION_LOST	Indicates that the connection to the eye tracker is lost
TOBII_RESEARCH_NOTIFICATION_CONNECTION_RESTORED	Indicates that the connection to the eye tracker is restored
TOBII_RESEARCH_NOTIFICATION_CALIBRATION_MODE_ENTERED	Indicates that the calibration mode is entered.
TOBII_RESEARCH_NOTIFICATION_CALIBRATION_MODE_LEFT	Indicates that the calibration mode is left.
TOBII_RESEARCH_NOTIFICATION_TRACK_BOX_CHANGED	Indicates that the track box is changed.
TOBII_RESEARCH_NOTIFICATION_DISPLAY_AREA_CHANGED	Indicates that the display area is changed.
TOBII_RESEARCH_NOTIFICATION_GAZE_OUTPUT_FREQUENCY_CHANGED	Indicates that the gaze output frequency is changed
TOBII_RESEARCH_NOTIFICATION_UNKNOWN

enum TobiiResearchStreamError

Defines error types

Enumerator
TOBII_RESEARCH_STREAM_ERROR_CONNECTION_LOST	Indicates that the connection to the eye tracker was lost.
TOBII_RESEARCH_STREAM_ERROR_INSUFFICIENT_LICENSE	Indicates that the license is insufficient for subscribing to the stream.
TOBII_RESEARCH_STREAM_ERROR_NOT_SUPPORTED	Indicates that the stream isn't supported by the eye tracker.
TOBII_RESEARCH_STREAM_ERROR_INTERNAL_ERROR	Indicates that an internal error occurred.
TOBII_RESEARCH_STREAM_ERROR_USER_ERROR	Indicates that the user threw an exception in the callback.

enum TobiiResearchStreamErrorSource

Defines error sources

Enumerator
TOBII_RESEARCH_STREAM_ERROR_SOURCE_USER	User callback failed.
TOBII_RESEARCH_STREAM_ERROR_SOURCE_STREAM_PUMP	Error when pumping event.
TOBII_RESEARCH_STREAM_ERROR_SOURCE_SUBSCRIPTION_GAZE_DATA	Error when subscribing to event for gaze data.
TOBII_RESEARCH_STREAM_ERROR_SOURCE_SUBSCRIPTION_EXTERNAL_SIGNAL	Error when subscribing to event for external signal.
TOBII_RESEARCH_STREAM_ERROR_SOURCE_SUBSCRIPTION_TIME_SYNCHRONIZATION_DATA	Error when subscribing to event for time synchronization data.
TOBII_RESEARCH_STREAM_ERROR_SOURCE_SUBSCRIPTION_EYE_IMAGE	Error when subscribing to event for eye images.
TOBII_RESEARCH_STREAM_ERROR_SOURCE_SUBSCRIPTION_NOTIFICATION	Error when subscribing to notification event.

enum TobiiResearchValidity

Specifies the validity.

Enumerator
TOBII_RESEARCH_VALIDITY_INVALID	Indicates invalid.
TOBII_RESEARCH_VALIDITY_VALID	Indicates valid.

Function Documentation

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_subscribe_to_external_signal_data	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_external_signal_data_callback	callback,
		void *	user_data
	)

Subscribes to external signal data for the eye tracker.

You will get a callback when the value of the external signal port (TTL input) on the eye tracker device changes. Not all eye trackers have an output trigger port. The output feature could be used to synchronize the eye tracker data with data from other devices. The output data contains a time reference that matches the time reference on the time synchronized gaze data.

void external_signal_callback(TobiiResearchExternalSignalData* external_signal_data, void* user_data) {
    (void)(user_data); // Is NULL, see subscription call
    printf("External signal: device time stamp %" PRId64 ", value %i \n",
            external_signal_data->device_time_stamp, external_signal_data->value);
}

void external_signal_example(TobiiResearchEyeTracker* eyetracker) {
    char* serial_number;
    tobii_research_get_serial_number(eyetracker, &serial_number);

    printf("Subscribing to external signal for eye tracker with serial number %s.\n", serial_number);

    tobii_research_free_string(serial_number);

    tobii_research_subscribe_to_external_signal_data(eyetracker, external_signal_callback, NULL);

    /* Wait for external signal. */
    sleep_ms(2000);

    tobii_research_unsubscribe_from_external_signal_data(eyetracker, external_signal_callback);
    printf("Unsubscribed from external signal.");

}

Parameters

eyetracker	Eye tracker object.
callback	Callback that will receive the external signal data.
user_data	Caller specific data that will be sent to the callback.

Returns

A TobiiResearchStatus code.

Examples:

external_signal.c.

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_subscribe_to_eye_image	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_eye_image_callback	callback,
		void *	user_data
	)

Subscribes to eye image for the eye tracker.

You will get a callback when a new eye image is received, and the occurrence depends on the eye tracker model. Not all eye tracker models support this feature. If no one is listening to gaze data, the eye tracker will only deliver full images, otherwise either cropped or full images will be delivered depending on whether or not the eye tracker has detected eyes.

void eye_image_callback(TobiiResearchEyeImage* frame, void* user_data) {
    const char* dir_path = (const char*)user_data;
    char img_path[256];
    FILE* fd;
    TiffHeader header = {
        .id=0x4949, // II little endian
        .version = 42, // Image version 
        .offset_first_ifd = sizeof(header) + (int32_t)frame->data_size // Offset to first IFD from start of file
    };
    TiffIFDEntry img_lenght = {.tag=257, .type=3, .N=1, .value=frame->height};      //  Image length (height)
    TiffIFDEntry img_width = {.tag=256, .type=3, .N=1, .value=frame->width};        //  Image  width
    TiffIFDEntry compression = {.tag=259, .type=3, .N=1, .value=1};                 //  Compression 1 = no compression
    TiffIFDEntry bits_per_sample = {.tag=258, .type=3, .N=1, .value=8};             //  BitsPerSample
    TiffIFDEntry strip_offsets = {.tag=273, .type=3, .N=1, .value=8};               //  StripOffsets 
    TiffIFDEntry samples_per_pixels = {.tag=277, .type=3, .N=1, .value=1};          //  SamplesPerPixel
    TiffIFDEntry photometric_interpretation = {.tag=262, .type=3, .N=1, .value=1};  //  PhotometricInterpretation
    int16_t number_of_ifd_entries = 7;
    int16_t next_ifd_offset = 0;  // 0, hence no more IFD in this file

    sprintf(img_path, "%s/eye_image_%" PRId64 ".tif", dir_path, frame->device_time_stamp); // Create image name
    printf("Received image %s\n", img_path);

    fd = fopen(img_path, "wb");

    fwrite(&header, sizeof(header), 1, fd);        // Writing header
    fwrite(frame->data, frame->data_size, 1, fd);  // Writing image data to file

    // Writing IFD entries, starts with number of entries
    fwrite(&number_of_ifd_entries, 1, sizeof(number_of_ifd_entries), fd);       

    fwrite(&img_lenght, 1, sizeof(img_lenght), fd);
    fwrite(&img_width, 1, sizeof(img_width), fd);
    fwrite(&compression, 1, sizeof(compression), fd);
    fwrite(&bits_per_sample, 1, sizeof(bits_per_sample), fd);
    fwrite(&strip_offsets, 1, sizeof(strip_offsets), fd);
    fwrite(&samples_per_pixels, 1, sizeof(samples_per_pixels), fd);
    fwrite(&photometric_interpretation, 1, sizeof(photometric_interpretation), fd);  

    fwrite(&next_ifd_offset, 1, sizeof(next_ifd_offset), fd);

    fclose(fd);
}

void eye_images_example(TobiiResearchEyeTracker* eyetracker, const char* dir_path) {
    /* Subscribe to eye images */
    tobii_research_subscribe_to_eye_image(eyetracker, eye_image_callback, (void*)dir_path);

    /* Wait for eye images. */
    sleep_ms(2000);

    /* Unsubscribe to eye images */
    tobii_research_unsubscribe_from_eye_image(eyetracker, eye_image_callback);
}

Parameters

eyetracker	Eye tracker object.
callback	Callback that will receive the frames.
user_data	Caller specific data that will be sent to the callback.

Returns

A TobiiResearchStatus code.

Examples:

eye_images.c.

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_subscribe_to_eye_image_as_gif	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_eye_image_as_gif_callback	callback,
		void *	user_data
	)

Subscribes to eye image for the eye tracker with the image delivered in gif format.

You will get a callback when a new eye image is received, and the occurrence depends on the eye tracker model. Not all eye tracker models support this feature. If no one is listening to gaze data, the eye tracker will only deliver full images, otherwise either cropped or full images will be delivered depending on whether or not the eye tracker has detected eyes.

void eye_image_as_gif_callback(TobiiResearchEyeImageGif* frame, void* user_data) {
    const char* dir_path = (const char*)user_data;
    char img_path[256];
    FILE* fd;
    sprintf(img_path, "%s/eye_image_%" PRId64 ".gif", dir_path, frame->device_time_stamp);
    printf("Received image %s\n", img_path);

    fd = fopen(img_path, "wb");
    fwrite(frame->image_data, frame->image_size, 1, fd);
    fclose(fd);
}

void eye_images_as_gif_example(TobiiResearchEyeTracker* eyetracker, const char* dir_path) {
    /* Subscribe to eye images */
    tobii_research_subscribe_to_eye_image_as_gif(
            eyetracker,
            eye_image_as_gif_callback, (void*)dir_path);

    /* Wait for eye images. */
    sleep_ms(2000);

    /* Unsubscribe to eye images */
    tobii_research_unsubscribe_from_eye_image_as_gif(
            eyetracker,
            eye_image_as_gif_callback);
}

Parameters

eyetracker	Eye tracker object.
callback	Callback that will receive the frames.
user_data	Caller specific data that will be sent to the callback.

Returns

A TobiiResearchStatus code.

Examples:

eye_images_as_gif.c.

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_subscribe_to_gaze_data	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_gaze_data_callback	callback,
		void *	user_data
	)

Subscribes to gaze data for the eye tracker.

You will get a callback when time synchronized gaze is received.Time synchronized gaze is not supported on all eye trackers, other eye trackers need additional license to activate this support.

void gaze_data_callback(TobiiResearchGazeData* gaze_data, void* user_data) {
    memcpy(user_data, gaze_data, sizeof(*gaze_data));
}

void gaze_data_example(TobiiResearchEyeTracker* eyetracker) {


    TobiiResearchGazeData gaze_data;
    char* serial_number;
    tobii_research_get_serial_number(eyetracker, &serial_number);

    printf("Subscribing to gaze data for eye tracker with serial number %s.\n", serial_number);

    tobii_research_free_string(serial_number);

    TobiiResearchStatus status = tobii_research_subscribe_to_gaze_data(eyetracker, gaze_data_callback, &gaze_data);

    if (status != TOBII_RESEARCH_STATUS_OK)
        return;

    /* Wait while some gaze data is collected. */
    sleep_ms(2000);

    status = tobii_research_unsubscribe_from_gaze_data(eyetracker, gaze_data_callback);
    printf("Unsubscribed from gaze data with status %i.\n", status);

    printf("Last received gaze package:\n");
    printf("System time stamp: %"  PRId64 "\n", gaze_data.system_time_stamp);
    printf("Device time stamp: %"  PRId64 "\n", gaze_data.device_time_stamp);
    printf("Left eye 2D gaze point on display area: (%f, %f)\n",
            gaze_data.left_eye.gaze_point.position_on_display_area.x,
            gaze_data.left_eye.gaze_point.position_on_display_area.y);
    printf("Right eye 3d gaze origin in user coordinates (%f, %f, %f)\n",
            gaze_data.right_eye.gaze_origin.position_in_user_coordinates.x,
            gaze_data.right_eye.gaze_origin.position_in_user_coordinates.y,
            gaze_data.right_eye.gaze_origin.position_in_user_coordinates.z);

    /* Wait while some gaze data is collected. */
    sleep_ms(2000);
}

Parameters

eyetracker	Eye tracker object.
callback	Callback that will receive the gaze data.
user_data	Caller specific data that will be sent to the callback.

Returns

A TobiiResearchStatus code.

Examples:

gaze_data.c.

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_subscribe_to_hmd_gaze_data	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_hmd_gaze_data_callback	callback,
		void *	user_data
	)

Subscribes to gaze data for the eye tracker.

Parameters

eyetracker	Eye tracker object.
callback	Callback that will receive the gaze data.
user_data	Caller specific data that will be sent to the callback.

Returns

A TobiiResearchStatus code.

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_subscribe_to_notifications	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_notification_callback	callback,
		void *	user_data
	)

Subscribes to notifications for the eye tracker.

You will get a callback when notification is received.

void notification_callback(TobiiResearchNotification* notification, void* user_data) {

    if (TOBII_RESEARCH_NOTIFICATION_CALIBRATION_MODE_ENTERED != notification->notification_type) {
        printf("Enter calibration mode notification received at time stamp %" PRId64 ".\n", notification->system_time_stamp);
    }

    if (TOBII_RESEARCH_NOTIFICATION_CALIBRATION_MODE_LEFT != notification->notification_type) {
        printf("Left calibration mode notification received at time stamp %" PRId64 ".\n", notification-> system_time_stamp);
    }
    (void)(user_data); // Is NULL, see subscription call

}

void notifications_example(TobiiResearchEyeTracker* eyetracker) {

    tobii_research_subscribe_to_notifications(eyetracker, notification_callback, NULL);

    /* Trigger some notifications */
    tobii_research_screen_based_calibration_enter_calibration_mode(eyetracker);

    tobii_research_screen_based_calibration_leave_calibration_mode(eyetracker);

    /* Unsubscribe from notifications. */
    tobii_research_unsubscribe_from_notifications(eyetracker, notification_callback);

}

Parameters

eyetracker	Eye tracker object.
callback	Callback that will receive the notifications.
user_data	Caller specific data that will be sent to the callback.

Returns

A TobiiResearchStatus code.

Examples:

notifications.c.

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_subscribe_to_stream_errors	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_stream_error_callback	callback,
		void *	user_data
	)

Subscribes to stream errors for the eye tracker.

You will get a callback when an error occurs on other streams. You can get errors when subscribing, when something happened to the connection in the stream pump or when an error was raised in a callback.

Parameters

eyetracker	Eye tracker object.
callback	Callback that will receive the stream errors.
user_data	Caller specific data that will be sent to the callback.

Returns

A TobiiResearchStatus code.

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_subscribe_to_time_synchronization_data	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_time_synchronization_data_callback	callback,
		void *	user_data
	)

Subscribes to time synchronization data for the eye tracker.

You will get a callback when the computer and the eye trackers clocks gets synchronized. To handle normal drifts between clocks the clocks are checked on regular basis, and this results in that the time stamps are adjusted for the drifts in the data streams. This drift handling is done in real time. The data received from this event could be used for an even more accurate drift adjustment in the post processing.

void time_synchronization_data_callback(TobiiResearchTimeSynchronizationData* time_synchronization_data,
        void* user_data){
        (void)(user_data);  // Is NULL, see subscribing call
        printf("Device time stamp: %" PRId64 "\n", time_synchronization_data->device_time_stamp);
        printf("System request time stamp: %" PRId64 "\n", time_synchronization_data->system_request_time_stamp);
        printf("System response time stamp: %" PRId64 "\n", time_synchronization_data->system_response_time_stamp);
}


void time_synchronization_data_example(TobiiResearchEyeTracker* eyetracker) {

    char* serial_number;
    tobii_research_get_serial_number(eyetracker, &serial_number);

    printf("Subscribing to time synchronization data for eye tracker with serial number %s.\n", serial_number);

    tobii_research_free_string(serial_number);

    tobii_research_subscribe_to_time_synchronization_data(eyetracker, time_synchronization_data_callback, NULL);

    /* Wait while some time synchronization data is collected. */
    sleep_ms(2000);

    tobii_research_unsubscribe_from_time_synchronization_data(eyetracker, time_synchronization_data_callback);
    printf("Unsubscribed from time synchronization data.\n");
}

Parameters

eyetracker	Eye tracker object.
callback	Callback that will receive the time synchronization data.
user_data	Caller specific data that will be sent to the callback.

Returns

A TobiiResearchStatus code.

Examples:

time_synchronization_data.c.

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_unsubscribe_from_external_signal_data	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_external_signal_data_callback	callback
	)

Unsubscribes from external signal data for the eye tracker.

Parameters

eyetracker	Eye tracker object.
callback	Callback sent to tobii_research_subscribe_to_external_signal_data

Returns

A TobiiResearchStatus code.

Examples:

external_signal.c.

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_unsubscribe_from_eye_image	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_eye_image_callback	callback
	)

Unsubscribes from eye image for the eye tracker.

Parameters

eyetracker	Eye tracker object.
callback	Callback sent to tobii_research_subscribe_to_eye_image.

Returns

A TobiiResearchStatus code.

Examples:

eye_images.c.

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_unsubscribe_from_eye_image_as_gif	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_eye_image_as_gif_callback	callback
	)

Unsubscribes from eye image for the eye tracker.

Parameters

eyetracker	Eye tracker object.
callback	Callback sent to tobii_research_subscribe_to_eye_image_as_gif.

Returns

A TobiiResearchStatus code.

Examples:

eye_images_as_gif.c.

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_unsubscribe_from_gaze_data	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_gaze_data_callback	callback
	)

Unsubscribes from gaze data for the eye tracker.

Parameters

eyetracker	Eye tracker object.
callback	Callback sent to tobii_research_subscribe_to_gaze_data.

Returns

A TobiiResearchStatus code.

Examples:

gaze_data.c.

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_unsubscribe_from_hmd_gaze_data	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_hmd_gaze_data_callback	callback
	)

Unsubscribes from HMD gaze data for the eye tracker.

Parameters

eyetracker	Eye tracker object.
callback	Callback sent to tobii_research_subscribe_to_hmd_gaze_data.

Returns

A TobiiResearchStatus code.

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_unsubscribe_from_notifications	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_notification_callback	callback
	)

Unsubscribes from notifications for the eye tracker.

Parameters

eyetracker	Eye tracker object.
callback	Callback sent to tobii_research_subscribe_to_notifications.

Returns

A TobiiResearchStatus code.

Examples:

notifications.c.

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_unsubscribe_from_stream_errors	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_stream_error_callback	callback
	)

Unsubscribes from stream errors for the eye tracker.

Parameters

eyetracker	Eye tracker object.
callback	Callback sent to tobii_research_subscribe_to_stream_errors.

Returns

A TobiiResearchStatus code.

TOBII_RESEARCH_API TobiiResearchStatus TOBII_RESEARCH_CALL tobii_research_unsubscribe_from_time_synchronization_data	(	TobiiResearchEyeTracker *	eyetracker,
		tobii_research_time_synchronization_data_callback	callback
	)

Unsubscribes from time synchronization data for the eye tracker.

Parameters

eyetracker	Eye tracker object.
callback	Callback sent to tobii_research_subscribe_to_time_synchronization_data.

Returns

A TobiiResearchStatus code.

Examples:

time_synchronization_data.c.