contrib: add a HOWTO for new users

[libam7xxx.git] / src / am7xxx.h

diff --git a/src/am7xxx.h b/src/am7xxx.h
index 5b5f111..d103c22 100644 (file)
--- a/src/am7xxx.h
+++ b/src/am7xxx.h
@@ -1,6 +1,6 @@
 /* am7xxx - communication with AM7XXX based USB Pico Projectors and DPFs
  *
 /* am7xxx - communication with AM7XXX based USB Pico Projectors and DPFs
  *

- * Copyright (C) 2012  Antonio Ospite <ospite@studenti.unina.it>
+ * Copyright (C) 2012-2014  Antonio Ospite <ao2@ao2.it>

  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by


@@ -16,82 +16,297 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 

+/**
+ * @file
+ * Public libam7xxx API.
+ */
+

 #ifndef __AM7XXX_H
 #define __AM7XXX_H
 
 #ifndef __AM7XXX_H
 #define __AM7XXX_H
 

-#include <stdint.h>
-#include <libusb-1.0/libusb.h>
-

 #ifdef __cplusplus
 extern "C" {
 #endif
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 

-typedef libusb_device_handle *am7xxx_device;

 
 

+/**
+ * @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 {
 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;
+       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 {
 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;
 
 } 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 {
 typedef enum {

-       AM7XXX_POWER_OFF  = 0,
-       AM7XXX_POWER_LOW  = 1,
-       AM7XXX_POWER_MID  = 2,
-       AM7XXX_POWER_HIGH = 3,
+       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;
 
 } am7xxx_power_mode;
 

-struct am7xxx_image_header {
-       uint32_t format;
-       uint32_t width;
-       uint32_t height;
-       uint32_t image_size;
-};
+/**
+ * The display zoom modes.
+ *
+ * An am7xxx device can display images using several zoom modes.
+ *
+ * @note Changing the zoom mode can change the aspect ratio of the displayed
+ * image.
+ *
+ * @note On the zoom test screen the version of the firmware running on the
+ * device is shown as well (e.g SPI_V21.0.0_2011.03.18).
+ *
+ * @note The Tele mode is available only on some PicoPix models, when using it
+ * the image is distorted like if a different lens was used, but the global
+ * aspect ratio of the image does not change.
+ */
+typedef enum {
+       AM7XXX_ZOOM_ORIGINAL = 0, /**< Original Size, as retrieved via #am7xxx_device_info. */
+       AM7XXX_ZOOM_H        = 1, /**< Zoom 1: H Scale (changes aspect ratio). */
+       AM7XXX_ZOOM_H_V      = 2, /**< Zoom 2: H/V Scale (changes aspect ratio). */
+       AM7XXX_ZOOM_TEST     = 3, /**< Zoom test screen, the firmware version is shown as well. */
+       AM7XXX_ZOOM_TELE     = 4, /**< Zoom Tele: available on some PicoPix models. */
+} am7xxx_zoom_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);

 
 

-struct am7xxx_power_header {
-       uint32_t power_low;
-       uint32_t power_mid;
-       uint32_t power_high;
-};
+/**
+ * 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.
+ *
+ * @note The level is per-context.

  *
  *

- * 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 Messages of level AM7XXX_LOG_FATAL are always shown, regardless
+ * of the value of the log_level parameter.

  *
  *

- * 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
+ * @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);

 
 

-struct am7xxx_header {
-       uint32_t packet_type;
-       uint8_t unknown0;
-       uint8_t header_data_len;
-       uint8_t unknown2;
-       uint8_t unknown3;
-       union {
-               struct am7xxx_image_header image;
-               struct am7xxx_power_header power;
-       } header_data;
-};
+/**
+ * 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);

 
 

-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 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 an 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,
                      am7xxx_image_format format,
                      unsigned int width,
                      unsigned int height,

-                     uint8_t *image,
-                     unsigned int size);
+                     unsigned char *image,
+                     unsigned int image_size);
+
+/**
+ * Queue transfer of an image for display on an am7xxx device and return immediately.
+ *
+ * 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.
+ *
+ * @note This _async() variant makes a copy of the image buffer, so the caller
+ * is free to reuse the buffer just after the function returns.
+ *
+ * @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_async(am7xxx_device *dev,
+                           am7xxx_image_format format,
+                           unsigned int width,
+                           unsigned int height,
+                           unsigned char *image,
+                           unsigned int image_size);
+
+/**
+ * Set the power mode of an am7xxx device.
+ *
+ * @note When setting the mode to AM7XXX_POWER_OFF the display can't be turned
+ * on again by using only am7xxx_set_power_mode(), am7xxx_set_zoom_mode() has
+ * to be called first, the current guess is that the latter performs some
+ * other resets beside setting the zoom mode.
+ *
+ * @param[in] dev A pointer to the structure representing the device to set power mode to
+ * @param[in] power The power mode to put the device in (see #am7xxx_power_mode enum)
+ *
+ * @return 0 on success, a negative value on error
+ *
+ */
+int am7xxx_set_power_mode(am7xxx_device *dev, am7xxx_power_mode power);
+
+/**
+ * Set the zoom mode of an am7xxx device.
+ *
+ * @note When setting the mode to AM7XXX_ZOOM_TEST, the calling program might
+ * want to skip displaying actual images.
+ *
+ * @note It looks like that power mode and zoom mode are related somehow wrt.
+ * resetting the operational mode after AM7XXX_POWER_OFF, applications can
+ * restore the display properly using this combination:
+ *  - Off: power mode 0, zoom mode 3
+ *  - On: power mode != 0, zoom mode != 3
+ *
+ * @param[in] dev A pointer to the structure representing the device to set zoom mode to
+ * @param[in] zoom The zoom mode to put the device in (see #am7xxx_zoom_mode enum)
+ *
+ * @return 0 on success, a negative value on error
+ *
+ */
+int am7xxx_set_zoom_mode(am7xxx_device *dev, am7xxx_zoom_mode zoom);

 
 #ifdef __cplusplus
 }
 
 #ifdef __cplusplus
 }