X-Git-Url: https://git.ao2.it/libam7xxx.git/blobdiff_plain/ad32c9df36e8ec1c5b336bdad10ae771298b4d39..8f7b53699838c5d9895eeb8995bb74b38a5f733e:/src/am7xxx.h?ds=sidebyside diff --git a/src/am7xxx.h b/src/am7xxx.h index 6847796..df305e5 100644 --- a/src/am7xxx.h +++ b/src/am7xxx.h @@ -16,105 +16,227 @@ * along with this program. If not, see . */ +/** + * @file + * Public libam7xxx API. + */ + #ifndef __AM7XXX_H #define __AM7XXX_H -#include -#include - #ifdef __cplusplus extern "C" { #endif -typedef libusb_device_handle *am7xxx_device; -typedef enum { - AM7XXX_PACKET_TYPE_INIT = 0x01, - AM7XXX_PACKET_TYPE_IMAGE = 0x02, - AM7XXX_PACKET_TYPE_POWER = 0x04, - AM7XXX_PACKET_TYPE_UNKNOWN = 0x05, -} am7xxx_packet_type; +/** + * @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; /**< 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, /**< 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. */ + AM7XXX_POWER_HIGH = 3, /**< More brightness, but more power consumption. */ + AM7XXX_POWER_TURBO = 4, /**< Max brightness and power consumprion. This may need both the Master and Slave USB connectors plugged. */ } am7xxx_power_mode; -struct am7xxx_generic_header { - uint32_t field0; - uint32_t field1; - uint32_t field2; - uint32_t field3; -}; - -struct am7xxx_image_header { - uint32_t format; - uint32_t width; - uint32_t height; - uint32_t image_size; -}; +/** + * 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); -struct am7xxx_power_header { - uint32_t bit2; - uint32_t bit1; - uint32_t bit0; -}; +/** + * Cleanup the library data structures and free the context. + * + * @param[in,out] ctx The context to free. + */ +void am7xxx_shutdown(am7xxx_context *ctx); -/* - * Examples of packet headers: +/** + * Set verbosity level of log messages. * - * Image header: - * 02 00 00 00 00 10 3e 10 01 00 00 00 20 03 00 00 e0 01 00 00 53 E8 00 00 + * @note The level is per-context. * - * Power header: - * 04 00 00 00 00 0c ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + * @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); -/* The header size on the wire is known to be always 24 bytes, regardless of - * the memory configuration enforced by different architechtures or compilers - * for struct am7xxx_header +/** + * 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 */ -#define AM7XXX_HEADER_WIRE_SIZE 24 - -struct am7xxx_header { - uint32_t packet_type; - uint8_t unknown0; - uint8_t header_data_len; - uint8_t unknown2; - uint8_t unknown3; - union { - struct am7xxx_generic_header data; - struct am7xxx_image_header image; - struct am7xxx_power_header power; - } header_data; -}; +int am7xxx_open_device(am7xxx_context *ctx, + am7xxx_device **dev, + unsigned int device_index); -am7xxx_device am7xxx_init(void); +/** + * 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); -void am7xxx_shutdown(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); -int am7xxx_send_image(am7xxx_device dev, +/** + * 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 dimesions + * @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 int height, - uint8_t *image, - unsigned int size); + 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); +int am7xxx_set_power_mode(am7xxx_device *dev, am7xxx_power_mode mode); #ifdef __cplusplus }