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:breadcrumbs: <a href="../../index.html">Home</a> / <a href="../../index.html#software-c">Software</a> / C/C++ - Color Bricklet

.. |device_identifier_constant| replace:: There is also a :ref:`constant <color_bricklet_c_constants>` for the device identifier of this Bricklet.

.. _color_bricklet_c:

C/C++ - Color Bricklet
======================

This is the description of the :ref:`C/C++ API bindings <api_bindings_c>` for the :ref:`Color Bricklet <color_bricklet>`. General information and technical
specifications for the Color Bricklet are summarized in its :ref:`hardware description
<color_bricklet_description>`.

An :ref:`installation guide <api_bindings_c_install>` for the C/C++ API
bindings is part of their general description.

.. _color_bricklet_c_examples:


Examples
--------

The example code below is `Public Domain (CC0 1.0)
<http://creativecommons.org/publicdomain/zero/1.0/>`__.

Simple
^^^^^^

`Download (example_simple.c) <https://github.com/Tinkerforge/color-bricklet/raw/master/software/examples/c/example_simple.c>`__

.. literalinclude:: Color_Bricklet_C_example_simple.c
 :language: c
 :linenos:
 :tab-width: 4

Callback
^^^^^^^^

`Download (example_callback.c) <https://github.com/Tinkerforge/color-bricklet/raw/master/software/examples/c/example_callback.c>`__

.. literalinclude:: Color_Bricklet_C_example_callback.c
 :language: c
 :linenos:
 :tab-width: 4

Threshold
^^^^^^^^^

`Download (example_threshold.c) <https://github.com/Tinkerforge/color-bricklet/raw/master/software/examples/c/example_threshold.c>`__

.. literalinclude:: Color_Bricklet_C_example_threshold.c
 :language: c
 :linenos:
 :tab-width: 4

.. _color_bricklet_c_api:

API
---

Every function of the C/C++ bindings returns an integer which describes an
error code. Data returned from the device, when a getter is called,
is handled via call by reference. These parameters are labeled with the
``ret_`` prefix.

Possible error codes are:

* E_OK = 0
* E_TIMEOUT = -1
* E_NO_STREAM_SOCKET = -2
* E_HOSTNAME_INVALID = -3
* E_NO_CONNECT = -4
* E_NO_THREAD = -5
* E_NOT_ADDED = -6 (unused since bindings version 2.0.0)
* E_ALREADY_CONNECTED = -7
* E_NOT_CONNECTED = -8
* E_INVALID_PARAMETER = -9
* E_NOT_SUPPORTED = -10
* E_UNKNOWN_ERROR_CODE = -11

as defined in :file:`ip_connection.h`.

All functions listed below are thread-safe.




Basic Functions
^^^^^^^^^^^^^^^


.. c:function:: void color_create(Color *color, const char *uid, IPConnection *ipcon)

 Creates the device object ``color`` with the unique device ID ``uid`` and adds
 it to the IPConnection ``ipcon``:

 .. code-block:: c

    Color color;
    color_create(&color, "YOUR_DEVICE_UID", &ipcon);

 This device object can be used after the IP connection has been connected
 (see examples :ref:`above <color_bricklet_c_examples>`).

.. c:function:: void color_destroy(Color *color)

 Removes the device object ``color`` from its IPConnection and destroys it.
 The device object cannot be used anymore afterwards.


.. c:function:: int color_get_color(Color *color, uint16_t *ret_r, uint16_t *ret_g, uint16_t *ret_b, uint16_t *ret_c)

 Returns the measured color of the sensor. The values
 have a range of 0 to 65535.
 
 The red (r), green (g), blue (b) and clear (c) colors are measured
 with four different photodiodes that are responsive at different
 wavelengths:
 
 .. image:: /Images/Bricklets/bricklet_color_wavelength_chart_600.jpg
    :scale: 100 %
    :alt: Chart Responsivity / Wavelength
    :align: center
    :target: ../../_images/Bricklets/bricklet_color_wavelength_chart_600.jpg
 
 If you want to get the color periodically, it is recommended 
 to use the callback :c:data:`COLOR_CALLBACK_COLOR` and set the period with 
 :c:func:`color_set_color_callback_period`.
 
.. c:function:: int color_light_on(Color *color)

 Turns the LED on.
 
.. c:function:: int color_light_off(Color *color)

 Turns the LED off.
 
.. c:function:: int color_is_light_on(Color *color, uint8_t *ret_light)

 Returns the state of the LED. Possible values are:
 
 * 0: On
 * 1: Off
 
 The following defines are available for this function:
 
 * COLOR_LIGHT_ON = 0
 * COLOR_LIGHT_OFF = 1
 
.. c:function:: int color_set_config(Color *color, uint8_t gain, uint8_t integration_time)

 Sets the configuration of the sensor. Gain and integration time
 can be configured in this way.
 
 For configuring the gain:
 
 * 0: 1x Gain
 * 1: 4x Gain
 * 2: 16x Gain
 * 3: 60x Gain
 
 For configuring the integration time:
 
 * 0: 2.4ms
 * 1: 24ms
 * 2: 101ms
 * 3: 154ms
 * 4: 700ms
 
 Increasing the gain enables the sensor to detect a
 color from a higher distance.
 
 The integration time provides a trade-off between conversion time
 and accuracy. With a longer integration time the values read will
 be more accurate but it will take longer time to get the conversion
 results.
 
 The default values are 60x gain and 154ms integration time.
 
 The following defines are available for this function:
 
 * COLOR_GAIN_1X = 0
 * COLOR_GAIN_4X = 1
 * COLOR_GAIN_16X = 2
 * COLOR_GAIN_60X = 3
 * COLOR_INTEGRATION_TIME_2MS = 0
 * COLOR_INTEGRATION_TIME_24MS = 1
 * COLOR_INTEGRATION_TIME_101MS = 2
 * COLOR_INTEGRATION_TIME_154MS = 3
 * COLOR_INTEGRATION_TIME_700MS = 4
 
.. c:function:: int color_get_config(Color *color, uint8_t *ret_gain, uint8_t *ret_integration_time)

 Returns the configuration as set by :c:func:`color_set_config`.
 
 The following defines are available for this function:
 
 * COLOR_GAIN_1X = 0
 * COLOR_GAIN_4X = 1
 * COLOR_GAIN_16X = 2
 * COLOR_GAIN_60X = 3
 * COLOR_INTEGRATION_TIME_2MS = 0
 * COLOR_INTEGRATION_TIME_24MS = 1
 * COLOR_INTEGRATION_TIME_101MS = 2
 * COLOR_INTEGRATION_TIME_154MS = 3
 * COLOR_INTEGRATION_TIME_700MS = 4
 
.. c:function:: int color_get_illuminance(Color *color, uint32_t *ret_illuminance)

 Returns the illuminance affected by the gain and integration time as
 set by :c:func:`color_set_config`. To get the illuminance in Lux apply this formula::
 
  lux = illuminance * 700 / gain / integration_time
 
 To get a correct illuminance measurement make sure that the color
 values themself are not saturated. The color value (R, G or B)
 is saturated if it is equal to the maximum value of 65535.
 In that case you have to reduce the gain, see :c:func:`color_set_config`.
 
.. c:function:: int color_get_color_temperature(Color *color, uint16_t *ret_color_temperature)

 Returns the color temperature in Kelvin.
 
 To get a correct color temperature measurement make sure that the color
 values themself are not saturated. The color value (R, G or B)
 is saturated if it is equal to the maximum value of 65535.
 In that case you have to reduce the gain, see :c:func:`color_set_config`.
 


Advanced Functions
^^^^^^^^^^^^^^^^^^

.. c:function:: int color_get_api_version(Color *color, uint8_t ret_api_version[3])

 Returns the version of the API definition (major, minor, revision) implemented
 by this API bindings. This is neither the release version of this API bindings
 nor does it tell you anything about the represented Brick or Bricklet.
 
.. c:function:: int color_get_response_expected(Color *color, uint8_t function_id, bool *ret_response_expected)

 Returns the response expected flag for the function specified by the function
 ID parameter. It is *true* if the function is expected to send a response,
 *false* otherwise.
 
 For getter functions this is enabled by default and cannot be disabled,
 because those functions will always send a response. For callback configuration
 functions it is enabled by default too, but can be disabled by
 :c:func:`color_set_response_expected`. For setter functions it is disabled by default
 and can be enabled.
 
 Enabling the response expected flag for a setter function allows to detect
 timeouts and other error conditions calls of this setter as well. The
 device will then send a response for this purpose. If this flag is disabled for
 a setter function then no response is send and errors are silently ignored,
 because they cannot be detected.
 
 See :c:func:`color_set_response_expected`
 for the list of function ID defines available for this function.
 
.. c:function:: int color_set_response_expected(Color *color, uint8_t function_id, bool response_expected)

 Changes the response expected flag of the function specified by the
 function ID parameter. This flag can only be changed for setter (default value:
 *false*) and callback configuration functions (default value: *true*). For
 getter functions it is always enabled and callbacks it is always disabled.
 
 Enabling the response expected flag for a setter function allows to detect
 timeouts and other error conditions calls of this setter as well. The
 device will then send a response for this purpose. If this flag is disabled for
 a setter function then no response is send and errors are silently ignored,
 because they cannot be detected.
 
 The following function ID defines are available for this function:
 
 * COLOR_FUNCTION_SET_COLOR_CALLBACK_PERIOD = 2
 * COLOR_FUNCTION_SET_COLOR_CALLBACK_THRESHOLD = 4
 * COLOR_FUNCTION_SET_DEBOUNCE_PERIOD = 6
 * COLOR_FUNCTION_LIGHT_ON = 10
 * COLOR_FUNCTION_LIGHT_OFF = 11
 * COLOR_FUNCTION_SET_CONFIG = 13
 * COLOR_FUNCTION_SET_ILLUMINANCE_CALLBACK_PERIOD = 17
 * COLOR_FUNCTION_SET_COLOR_TEMPERATURE_CALLBACK_PERIOD = 19
 
.. c:function:: int color_set_response_expected_all(Color *color, bool response_expected)

 Changes the response expected flag for all setter and callback configuration
 functions of this device at once.
 
.. c:function:: int color_get_identity(Color *color, char ret_uid[8], char ret_connected_uid[8], char *ret_position, uint8_t ret_hardware_version[3], uint8_t ret_firmware_version[3], uint16_t *ret_device_identifier)

 Returns the UID, the UID where the Bricklet is connected to, 
 the position, the hardware and firmware version as well as the
 device identifier.
 
 The position can be 'a', 'b', 'c' or 'd'.
 
 The device identifier numbers can be found :ref:`here <device_identifier>`.
 |device_identifier_constant|
 


Callback Configuration Functions
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


.. c:function:: void color_register_callback(Color *color, uint8_t id, void *callback, void *user_data)

 Registers a callback with ID ``id`` to the function ``callback``. The
 ``user_data`` will be given as a parameter of the callback.

 The available IDs with corresponding function signatures are listed
 :ref:`below <color_bricklet_c_callbacks>`.


.. c:function:: int color_set_color_callback_period(Color *color, uint32_t period)

 Sets the period in ms with which the :c:data:`COLOR_CALLBACK_COLOR` callback is triggered
 periodically. A value of 0 turns the callback off.
 
 :c:data:`COLOR_CALLBACK_COLOR` is only triggered if the color has changed since the
 last triggering.
 
 The default value is 0.
 
.. c:function:: int color_get_color_callback_period(Color *color, uint32_t *ret_period)

 Returns the period as set by :c:func:`color_set_color_callback_period`.
 
.. c:function:: int color_set_color_callback_threshold(Color *color, char option, uint16_t min_r, uint16_t max_r, uint16_t min_g, uint16_t max_g, uint16_t min_b, uint16_t max_b, uint16_t min_c, uint16_t max_c)

 Sets the thresholds for the :c:data:`COLOR_CALLBACK_COLOR_REACHED` callback. 
 
 The following options are possible:
 
 .. csv-table::
  :header: "Option", "Description"
  :widths: 10, 100
 
  "'x'",    "Callback is turned off"
  "'o'",    "Callback is triggered when the temperature is *outside* the min and max values"
  "'i'",    "Callback is triggered when the temperature is *inside* the min and max values"
  "'<'",    "Callback is triggered when the temperature is smaller than the min value (max is ignored)"
  "'>'",    "Callback is triggered when the temperature is greater than the min value (max is ignored)"
 
 The default value is ('x', 0, 0, 0, 0, 0, 0, 0, 0).
 
 The following defines are available for this function:
 
 * COLOR_THRESHOLD_OPTION_OFF = 'x'
 * COLOR_THRESHOLD_OPTION_OUTSIDE = 'o'
 * COLOR_THRESHOLD_OPTION_INSIDE = 'i'
 * COLOR_THRESHOLD_OPTION_SMALLER = '<'
 * COLOR_THRESHOLD_OPTION_GREATER = '>'
 
.. c:function:: int color_get_color_callback_threshold(Color *color, char *ret_option, uint16_t *ret_min_r, uint16_t *ret_max_r, uint16_t *ret_min_g, uint16_t *ret_max_g, uint16_t *ret_min_b, uint16_t *ret_max_b, uint16_t *ret_min_c, uint16_t *ret_max_c)

 Returns the threshold as set by :c:func:`color_set_color_callback_threshold`.
 
 The following defines are available for this function:
 
 * COLOR_THRESHOLD_OPTION_OFF = 'x'
 * COLOR_THRESHOLD_OPTION_OUTSIDE = 'o'
 * COLOR_THRESHOLD_OPTION_INSIDE = 'i'
 * COLOR_THRESHOLD_OPTION_SMALLER = '<'
 * COLOR_THRESHOLD_OPTION_GREATER = '>'
 
.. c:function:: int color_set_debounce_period(Color *color, uint32_t debounce)

 Sets the period in ms with which the threshold callback
 
 * :c:data:`COLOR_CALLBACK_COLOR_REACHED`
 
 is triggered, if the threshold
 
 * :c:func:`color_set_color_callback_threshold`
 
 keeps being reached.
 
 The default value is 100.
 
.. c:function:: int color_get_debounce_period(Color *color, uint32_t *ret_debounce)

 Returns the debounce period as set by :c:func:`color_set_debounce_period`.
 
.. c:function:: int color_set_illuminance_callback_period(Color *color, uint32_t period)

 Sets the period in ms with which the :c:data:`COLOR_CALLBACK_ILLUMINANCE` callback is triggered
 periodically. A value of 0 turns the callback off.
 
 :c:data:`COLOR_CALLBACK_ILLUMINANCE` is only triggered if the illuminance has changed since the
 last triggering.
 
 The default value is 0.
 
.. c:function:: int color_get_illuminance_callback_period(Color *color, uint32_t *ret_period)

 Returns the period as set by :c:func:`color_set_illuminance_callback_period`.
 
.. c:function:: int color_set_color_temperature_callback_period(Color *color, uint32_t period)

 Sets the period in ms with which the :c:data:`COLOR_CALLBACK_COLOR_TEMPERATURE` callback is triggered
 periodically. A value of 0 turns the callback off.
 
 :c:data:`COLOR_CALLBACK_COLOR_TEMPERATURE` is only triggered if the color temperature has changed since the
 last triggering.
 
 The default value is 0.
 
.. c:function:: int color_get_color_temperature_callback_period(Color *color, uint32_t *ret_period)

 Returns the period as set by :c:func:`color_set_color_temperature_callback_period`.
 


.. _color_bricklet_c_callbacks:

Callbacks
^^^^^^^^^

Callbacks can be registered to receive
time critical or recurring data from the device. The registration is done
with the :c:func:`color_register_callback` function. The parameters consist of
the device object, the callback ID, the callback function and optional
user data:

 .. code-block:: c

    void my_callback(int p, void *user_data) {
        printf("parameter: %d\n", p);
    }

    color_register_callback(&color, COLOR_CALLBACK_EXAMPLE, (void *)my_callback, NULL);

The available constants with corresponding callback function signatures
are described below.

.. note::
 Using callbacks for recurring events is *always* preferred
 compared to using getters. It will use less USB bandwidth and the latency
 will be a lot better, since there is no round trip time.

.. c:var:: COLOR_CALLBACK_COLOR

 .. code-block:: c

  void callback(uint16_t r, uint16_t g, uint16_t b, uint16_t c, void *user_data)


 This callback is triggered periodically with the period that is set by
 :c:func:`color_set_color_callback_period`. The parameter is the color
 of the sensor as RGBC.
 
 :c:data:`COLOR_CALLBACK_COLOR` is only triggered if the color has changed since the
 last triggering.
 
.. c:var:: COLOR_CALLBACK_COLOR_REACHED

 .. code-block:: c

  void callback(uint16_t r, uint16_t g, uint16_t b, uint16_t c, void *user_data)


 This callback is triggered when the threshold as set by
 :c:func:`color_set_color_callback_threshold` is reached.
 The parameter is the color
 of the sensor as RGBC.
 
 If the threshold keeps being reached, the callback is triggered periodically
 with the period as set by :c:func:`color_set_debounce_period`.
 
.. c:var:: COLOR_CALLBACK_ILLUMINANCE

 .. code-block:: c

  void callback(uint32_t illuminance, void *user_data)


 This callback is triggered periodically with the period that is set by
 :c:func:`color_set_illuminance_callback_period`. The parameter is the illuminance.
 See :c:func:`color_get_illuminance` for how to interpret this value.
 
 :c:data:`COLOR_CALLBACK_ILLUMINANCE` is only triggered if the illuminance has changed since the
 last triggering.
 
.. c:var:: COLOR_CALLBACK_COLOR_TEMPERATURE

 .. code-block:: c

  void callback(uint16_t color_temperature, void *user_data)


 This callback is triggered periodically with the period that is set by
 :c:func:`color_set_color_temperature_callback_period`. The parameter is the 
 color temperature in Kelvin.
 
 :c:data:`COLOR_CALLBACK_COLOR_TEMPERATURE` is only triggered if the color temperature has 
 changed since the last triggering.
 


.. _color_bricklet_c_constants:

Constants
^^^^^^^^^

.. c:var:: COLOR_DEVICE_IDENTIFIER

 This constant is used to identify a Color Bricklet.

 The :c:func:`color_get_identity` function and the :c:data:`IPCON_CALLBACK_ENUMERATE`
 callback of the IP Connection have a ``device_identifier`` parameter to specify
 the Brick's or Bricklet's type.

