* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+/**
+ * @file
+ * Public libam7xxx API.
+ */
+
#ifndef __AM7XXX_H
#define __AM7XXX_H
#endif
+/**
+ * @typedef am7xxx_context
+ *
+ * An opaque data type representing a context.
+ */
struct _am7xxx_context;
typedef struct _am7xxx_context am7xxx_context;
+/**
+ * @typedef am7xxx_device
+ *
+ * An opaque data type representing an am7xxx device.
+ */
struct _am7xxx_device;
typedef struct _am7xxx_device am7xxx_device;
+/**
+ * A struct describing device specific properties.
+ *
+ * A user program may want to inspect these before providing data to the
+ * device. For instance, when sending an image the user may want to rescale it
+ * to the device native width and height in order to be sure the image will be
+ * displayed in its entirety.
+ */
typedef struct {
- unsigned int native_width;
- unsigned int native_height;
+ unsigned int native_width; /**< The device native width. */
+ unsigned int native_height; /**< The device native height. */
} am7xxx_device_info;
+/**
+ * The verbosity level of logging messages.
+ *
+ * This can be set with am7xxx_set_log_level() and the level will be used
+ * internally by libam7xxx to adjust the granularity of the information
+ * exposed to the user about the internal library operations.
+ */
typedef enum {
- AM7XXX_LOG_FATAL = 0,
- AM7XXX_LOG_ERROR = 1,
- AM7XXX_LOG_WARNING = 2,
- AM7XXX_LOG_INFO = 3,
- AM7XXX_LOG_DEBUG = 4,
- AM7XXX_LOG_TRACE = 5,
+ AM7XXX_LOG_FATAL = 0, /**< Fatal messages, the user application should stop if it gets one of this. */
+ AM7XXX_LOG_ERROR = 1, /**< Error messages, typically they describe API functions failures. */
+ AM7XXX_LOG_WARNING = 2, /**< Warnings about conditions worth mentioning to the user. */
+ AM7XXX_LOG_INFO = 3, /**< Informations about the device operations. */
+ AM7XXX_LOG_DEBUG = 4, /**< Informations about the library internals. */
+ AM7XXX_LOG_TRACE = 5, /**< Verbose informations about the communication with the hardware. */
} am7xxx_log_level;
+/**
+ * The image formats accepted by the device.
+ */
typedef enum {
- AM7XXX_IMAGE_FORMAT_JPEG = 1,
- AM7XXX_IMAGE_FORMAT_NV12 = 2,
+ AM7XXX_IMAGE_FORMAT_JPEG = 1, /**< JPEG format. */
+ AM7XXX_IMAGE_FORMAT_NV12 = 2, /**< Raw YUV in the NV12 variant. */
} am7xxx_image_format;
+/**
+ * The device power modes.
+ *
+ * An am7xxx device can operate in several power modes. A certain power mode
+ * may have effect on the display brightness or on the device power
+ * consumption.
+ *
+ * @note Most am7xxx devices come with a Y-shaped USB cable with a Master and
+ * a Slave connector, higher power modes may require that both connectors are
+ * plugged in to the host system for the device to work properly.
+ *
+ * @note At higher power modes some devices may use a fan to cool down the
+ * internal hardware components, and hence may be noisier in this case.
+ */
typedef enum {
- AM7XXX_POWER_OFF = 0,
- AM7XXX_POWER_LOW = 1,
- AM7XXX_POWER_MIDDLE = 2,
- AM7XXX_POWER_HIGH = 3,
- AM7XXX_POWER_TURBO = 4,
+ AM7XXX_POWER_OFF = 0, /**< Display is powered off, no image shown. */
+ AM7XXX_POWER_LOW = 1, /**< Low power consumption but also low brightness. */
+ AM7XXX_POWER_MIDDLE = 2, /**< Middle level of brightness. This and upper modes need both the Master and Slave USB connectors plugged. */
+ AM7XXX_POWER_HIGH = 3, /**< More brightness, but more power consumption. */
+ AM7XXX_POWER_TURBO = 4, /**< Max brightness and power consumption. */
} am7xxx_power_mode;
+/**
+ * Initialize the library context and data structures, and scan for devices.
+ *
+ * @param[out] ctx A pointer to the context the library will be used in.
+ *
+ * @return 0 on success, a negative value on error
+ */
int am7xxx_init(am7xxx_context **ctx);
+/**
+ * Cleanup the library data structures and free the context.
+ *
+ * @param[in,out] ctx The context to free.
+ */
void am7xxx_shutdown(am7xxx_context *ctx);
+/**
+ * Set verbosity level of log messages.
+ *
+ * @note The level is per-context.
+ *
+ * @note Messages of level AM7XXX_LOG_FATAL are always shown, regardless
+ * of the value of the log_level parameter.
+ *
+ * @param[in] ctx The context to set the log level for
+ * @param[in] log_level The verbosity level to use in the context (see @link am7xxx_log_level @endlink)
+ */
void am7xxx_set_log_level(am7xxx_context *ctx, am7xxx_log_level log_level);
+/**
+ * Open an am7xxx_device according to a index.
+ *
+ * The semantics of the 'device_index' argument follows the order
+ * of the devices as found when scanning the bus at am7xxx_init() time.
+ *
+ * @note When the user tries to open a device already opened the function
+ * returns -EBUSY and the device is left open.
+ *
+ * @param[in] ctx The context to open the device in
+ * @param[out] dev A pointer to the structure representing the device to open
+ * @param[in] device_index The index of the device on the bus
+ *
+ * @return 0 on success, a negative value on error
+ */
int am7xxx_open_device(am7xxx_context *ctx,
am7xxx_device **dev,
unsigned int device_index);
+/**
+ * Close an am7xxx_device.
+ *
+ * Close an am7xxx_device so that it becomes available for some other
+ * user/process to open it.
+ *
+ * @param[in] dev A pointer to the structure representing the device to close
+ *
+ * @return 0 on success, a negative value on error
+ */
int am7xxx_close_device(am7xxx_device *dev);
+/**
+ * Get info about an am7xxx device.
+ *
+ * Get information about a device, in the form of a
+ * @link am7xxx_device_info @endlink structure.
+ *
+ * @param[in] dev A pointer to the structure representing the device to get info of
+ * @param[out] device_info A pointer to the structure where to store the device info (see @link am7xxx_device_info @endlink)
+ *
+ * @return 0 on success, a negative value on error
+ */
int am7xxx_get_device_info(am7xxx_device *dev,
am7xxx_device_info *device_info);
+/**
+ * Calculate the dimensions of an image to be shown on an am7xxx device.
+ *
+ * Before sending images bigger than the device native dimensions the user
+ * needs to rescale them, this utility function does the calculation in a way
+ * that the original image aspect ratio is preserved.
+ *
+ * @param[in] dev A pointer to the structure representing the device to get info of
+ * @param[in] upscale Whether to calculate scaled dimensions for images smaller than the native dimensions
+ * @param[in] original_width The width of the original image
+ * @param[in] original_height The height of the original image
+ * @param[out] scaled_width The width the rescaled image should have
+ * @param[out] scaled_height The height the rescaled image should have
+ *
+ * @return 0 on success, a negative value on error
+ */
+int am7xxx_calc_scaled_image_dimensions(am7xxx_device *dev,
+ unsigned int upscale,
+ unsigned int original_width,
+ unsigned int original_height,
+ unsigned int *scaled_width,
+ unsigned int *scaled_height);
+/**
+ * Send an image for display on a am7xxx device.
+ *
+ * This is the function that actually makes the device display something.
+ * Static pictures can be sent just once and the device will keep showing them
+ * until another image get sent or some command resets or turns off the display.
+ *
+ * @param[in] dev A pointer to the structure representing the device to get info of
+ * @param[in] format The format the image is in (see @link am7xxx_image_format @endlink enum)
+ * @param[in] width The width of the image
+ * @param[in] height The height of the image
+ * @param[in] image A buffer holding data in the format specified by the format parameter
+ * @param[in] image_size The size in bytes of the image buffer
+ *
+ * @return 0 on success, a negative value on error
+ */
int am7xxx_send_image(am7xxx_device *dev,
am7xxx_image_format format,
unsigned int width,
unsigned char *image,
unsigned int image_size);
-/*
- * NOTE: if we set the mode to AM7XXX_POWER_OFF we can't turn the
- * display on again by using only am7xxx_set_power_mode().
+/**
+ * Set the power mode of an am7xxx device.
+ *
+ * \note If we set the mode to AM7XXX_POWER_OFF we can't turn the
+ * display on again by using only am7xxx_set_power_mode(). This needs to be
+ * investigated, maybe some other command can reset the device.
+ *
+ * @param[in] dev A pointer to the structure representing the device to get info of
+ * @param[in] mode The power mode to put the device in (see @link am7xxx_power_mode @endlink enum)
+ *
+ * @return 0 on success, a negative value on error
*
- * Remember to mention that when writing the API doc.
*/
int am7xxx_set_power_mode(am7xxx_device *dev, am7xxx_power_mode mode);
projects / libam7xxx.git / blobdiff