Adding upstream version 0.23.93.upstream/0.23.93upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1587 insertions, 0 deletions

diff --git a/include/zbar.h b/include/zbar.h
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--- /dev/null
+++ b/include/zbar.h
@@ -0,0 +1,1587 @@
+/*------------------------------------------------------------------------
+ *  Copyright 2007-2010 (c) Jeff Brown <spadix@users.sourceforge.net>
+ *
+ *  This file is part of the ZBar Bar Code Reader.
+ *
+ *  The ZBar Bar Code Reader is free software; you can redistribute it
+ *  and/or modify it under the terms of the GNU Lesser Public License as
+ *  published by the Free Software Foundation; either version 2.1 of
+ *  the License, or (at your option) any later version.
+ *
+ *  The ZBar Bar Code Reader is distributed in the hope that it will be
+ *  useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ *  of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Lesser Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser Public License
+ *  along with the ZBar Bar Code Reader; if not, write to the Free
+ *  Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ *  Boston, MA  02110-1301  USA
+ *
+ *  http://sourceforge.net/projects/zbar
+ *------------------------------------------------------------------------*/
+#ifndef _ZBAR_H_
+#define _ZBAR_H_
+
+#include <stdint.h>
+
+/** @file
+ * ZBar Barcode Reader C API definition
+ */
+
+/** @mainpage
+ *
+ * interface to the barcode reader is available at several levels.
+ * most applications will want to use the high-level interfaces:
+ *
+ * @section high-level High-Level Interfaces
+ *
+ * these interfaces wrap all library functionality into an easy-to-use
+ * package for a specific toolkit:
+ * - the "GTK+ 2.x widget" may be used with GTK GUI applications.  a
+ *   Python wrapper is included for PyGtk
+ * - the @ref zbar::QZBar "Qt4 widget" may be used with Qt GUI
+ *   applications
+ * - the Processor interface (in @ref c-processor "C" or @ref
+ *   zbar::Processor "C++") adds a scanning window to an application
+ *   with no GUI.
+ *
+ * @section mid-level Intermediate Interfaces
+ *
+ * building blocks used to construct high-level interfaces:
+ * - the ImageScanner (in @ref c-imagescanner "C" or @ref
+ *   zbar::ImageScanner "C++") looks for barcodes in a library defined
+ *   image object
+ * - the Window abstraction (in @ref c-window "C" or @ref
+ *   zbar::Window "C++") sinks library images, displaying them on the
+ *   platform display
+ * - the Video abstraction (in @ref c-video "C" or @ref zbar::Video
+ *   "C++") sources library images from a video device
+ *
+ * @section low-level Low-Level Interfaces
+ *
+ * direct interaction with barcode scanning and decoding:
+ * - the Scanner (in @ref c-scanner "C" or @ref zbar::Scanner "C++")
+ *   looks for barcodes in a linear intensity sample stream
+ * - the Decoder (in @ref c-decoder "C" or @ref zbar::Decoder "C++")
+ *   extracts barcodes from a stream of bar and space widths
+ */
+
+#ifdef __cplusplus
+
+/** C++ namespace for library interfaces */
+namespace zbar
+{
+extern "C" {
+#endif
+
+/** @name Global library interfaces */
+/*@{*/
+
+/** "color" of element: bar or space. */
+typedef enum zbar_color_e
+{
+    ZBAR_SPACE = 0, /**< light area or space between bars */
+    ZBAR_BAR   = 1, /**< dark area or colored bar segment */
+} zbar_color_t;
+
+/** decoded symbol type. */
+typedef enum zbar_symbol_type_e
+{
+    ZBAR_NONE	     = 0,   /**< no symbol decoded */
+    ZBAR_PARTIAL     = 1,   /**< intermediate status */
+    ZBAR_EAN2	     = 2,   /**< GS1 2-digit add-on */
+    ZBAR_EAN5	     = 5,   /**< GS1 5-digit add-on */
+    ZBAR_EAN8	     = 8,   /**< EAN-8 */
+    ZBAR_UPCE	     = 9,   /**< UPC-E */
+    ZBAR_ISBN10	     = 10,  /**< ISBN-10 (from EAN-13). @since 0.4 */
+    ZBAR_UPCA	     = 12,  /**< UPC-A */
+    ZBAR_EAN13	     = 13,  /**< EAN-13 */
+    ZBAR_ISBN13	     = 14,  /**< ISBN-13 (from EAN-13). @since 0.4 */
+    ZBAR_COMPOSITE   = 15,  /**< EAN/UPC composite */
+    ZBAR_I25	     = 25,  /**< Interleaved 2 of 5. @since 0.4 */
+    ZBAR_DATABAR     = 34,  /**< GS1 DataBar (RSS). @since 0.11 */
+    ZBAR_DATABAR_EXP = 35,  /**< GS1 DataBar Expanded. @since 0.11 */
+    ZBAR_CODABAR     = 38,  /**< Codabar. @since 0.11 */
+    ZBAR_CODE39	     = 39,  /**< Code 39. @since 0.4 */
+    ZBAR_PDF417	     = 57,  /**< PDF417. @since 0.6 */
+    ZBAR_QRCODE	     = 64,  /**< QR Code. @since 0.10 */
+    ZBAR_SQCODE	     = 80,  /**< SQ Code. @since 0.20.1 */
+    ZBAR_CODE93	     = 93,  /**< Code 93. @since 0.11 */
+    ZBAR_CODE128     = 128, /**< Code 128 */
+
+    /*
+     * Please see _zbar_get_symbol_hash() if adding
+     * anything after 128
+     */
+
+    /** mask for base symbol type.
+     * @deprecated in 0.11, remove this from existing code
+     */
+    ZBAR_SYMBOL = 0x00ff,
+    /** 2-digit add-on flag.
+     * @deprecated in 0.11, a ::ZBAR_EAN2 component is used for
+     * 2-digit GS1 add-ons
+     */
+    ZBAR_ADDON2 = 0x0200,
+    /** 5-digit add-on flag.
+     * @deprecated in 0.11, a ::ZBAR_EAN5 component is used for
+     * 5-digit GS1 add-ons
+     */
+    ZBAR_ADDON5 = 0x0500,
+    /** add-on flag mask.
+     * @deprecated in 0.11, GS1 add-ons are represented using composite
+     * symbols of type ::ZBAR_COMPOSITE; add-on components use ::ZBAR_EAN2
+     * or ::ZBAR_EAN5
+     */
+    ZBAR_ADDON = 0x0700,
+} zbar_symbol_type_t;
+
+/** decoded symbol coarse orientation.
+ * @since 0.11
+ */
+typedef enum zbar_orientation_e
+{
+    ZBAR_ORIENT_UNKNOWN = -1, /**< unable to determine orientation */
+    ZBAR_ORIENT_UP,	      /**< upright, read left to right */
+    ZBAR_ORIENT_RIGHT,	      /**< sideways, read top to bottom */
+    ZBAR_ORIENT_DOWN,	      /**< upside-down, read right to left */
+    ZBAR_ORIENT_LEFT,	      /**< sideways, read bottom to top */
+} zbar_orientation_t;
+
+/** error codes. */
+typedef enum zbar_error_e
+{
+    ZBAR_OK = 0,	  /**< no error */
+    ZBAR_ERR_NOMEM,	  /**< out of memory */
+    ZBAR_ERR_INTERNAL,	  /**< internal library error */
+    ZBAR_ERR_UNSUPPORTED, /**< unsupported request */
+    ZBAR_ERR_INVALID,	  /**< invalid request */
+    ZBAR_ERR_SYSTEM,	  /**< system error */
+    ZBAR_ERR_LOCKING,	  /**< locking error */
+    ZBAR_ERR_BUSY,	  /**< all resources busy */
+    ZBAR_ERR_XDISPLAY,	  /**< X11 display error */
+    ZBAR_ERR_XPROTO,	  /**< X11 protocol error */
+    ZBAR_ERR_CLOSED,	  /**< output window is closed */
+    ZBAR_ERR_WINAPI,	  /**< windows system error */
+    ZBAR_ERR_NUM	  /**< number of error codes */
+} zbar_error_t;
+
+/** decoder configuration options.
+ * @since 0.4
+ */
+typedef enum zbar_config_e
+{
+    ZBAR_CFG_ENABLE = 0, /**< enable symbology/feature */
+    ZBAR_CFG_ADD_CHECK,	 /**< enable check digit when optional */
+    ZBAR_CFG_EMIT_CHECK, /**< return check digit when present */
+    ZBAR_CFG_ASCII,	 /**< enable full ASCII character set */
+    ZBAR_CFG_BINARY,	 /**< don't convert binary data to text */
+    ZBAR_CFG_NUM,	 /**< number of boolean decoder configs */
+
+    ZBAR_CFG_MIN_LEN = 0x20, /**< minimum data length for valid decode */
+    ZBAR_CFG_MAX_LEN,	     /**< maximum data length for valid decode */
+
+    ZBAR_CFG_UNCERTAINTY = 0x40, /**< required video consistency frames */
+
+    ZBAR_CFG_POSITION = 0x80, /**< enable scanner to collect position data */
+    ZBAR_CFG_TEST_INVERTED,   /**< if fails to decode, test inverted */
+
+    ZBAR_CFG_X_DENSITY = 0x100, /**< image scanner vertical scan density */
+    ZBAR_CFG_Y_DENSITY,		/**< image scanner horizontal scan density */
+} zbar_config_t;
+
+/** decoder symbology modifier flags.
+ * @since 0.11
+ */
+typedef enum zbar_modifier_e
+{
+    /** barcode tagged as GS1 (EAN.UCC) reserved
+     * (eg, FNC1 before first data character).
+     * data may be parsed as a sequence of GS1 AIs
+     */
+    ZBAR_MOD_GS1 = 0,
+
+    /** barcode tagged as AIM reserved
+     * (eg, FNC1 after first character or digit pair)
+     */
+    ZBAR_MOD_AIM,
+
+    /** number of modifiers */
+    ZBAR_MOD_NUM,
+} zbar_modifier_t;
+
+typedef enum video_control_type_e
+{
+    VIDEO_CNTL_INTEGER = 1,
+    VIDEO_CNTL_MENU,
+    VIDEO_CNTL_BUTTON,
+    VIDEO_CNTL_INTEGER64,
+    VIDEO_CNTL_STRING,
+    VIDEO_CNTL_BOOLEAN,
+} video_control_type_t;
+
+/** store video control menu
+ * @param name name of the menu item
+ * @param val integer value associated with the item
+ */
+typedef struct video_control_menu_s {
+    char *name;
+    int64_t value;
+} video_control_menu_t;
+
+/** store video controls
+ * @param name name of the control
+ * @param group name of the control group/class
+ * @param type type of the control
+ * @param min minimum value of control (if control is integer)
+ * @param max maximum value of control (if control is integer)
+ * @param def default value of control (if control is integer)
+ * @param step increment steps (if control is integer)
+ * @param menu menu array
+ * @param menu_size menu size
+ * @since 0.20
+ */
+typedef struct video_controls_s {
+    char *name;
+    char *group;
+    video_control_type_t type;
+
+    int64_t min, max, def;
+    uint64_t step;
+
+    unsigned int menu_size;
+    video_control_menu_t *menu;
+
+    void *next;
+
+    // video drivers may add extra private data in the end of this struct
+} video_controls_t;
+
+/** store a video resolution
+ * @param width width of the video window
+ * @param height length of the video window
+ * @param max_fps maximum streaming speed, in frames per second
+ * @since 0.22
+ */
+struct video_resolution_s {
+    unsigned int width, height;
+    float max_fps;
+};
+
+/** retrieve runtime library version information.
+ * @param major set to the running major version (unless NULL)
+ * @param minor set to the running minor version (unless NULL)
+ * @returns 0
+ */
+extern int zbar_version(unsigned *major, unsigned *minor, unsigned *patch);
+
+/** set global library debug level.
+ * @param verbosity desired debug level.  higher values create more spew
+ */
+extern void zbar_set_verbosity(int verbosity);
+
+/** increase global library debug level.
+ * eg, for -vvvv
+ */
+extern void zbar_increase_verbosity(void);
+
+/** retrieve string name for symbol encoding.
+ * @param sym symbol type encoding
+ * @returns the static string name for the specified symbol type,
+ * or "UNKNOWN" if the encoding is not recognized
+ */
+extern const char *zbar_get_symbol_name(zbar_symbol_type_t sym);
+
+/** retrieve string name for addon encoding.
+ * @param sym symbol type encoding
+ * @returns static string name for any addon, or the empty string
+ * if no addons were decoded
+ * @deprecated in 0.11
+ */
+extern const char *zbar_get_addon_name(zbar_symbol_type_t sym);
+
+/** retrieve string name for configuration setting.
+ * @param config setting to name
+ * @returns static string name for config,
+ * or the empty string if value is not a known config
+ */
+extern const char *zbar_get_config_name(zbar_config_t config);
+
+/** retrieve string name for modifier.
+ * @param modifier flag to name
+ * @returns static string name for modifier,
+ * or the empty string if the value is not a known flag
+ */
+extern const char *zbar_get_modifier_name(zbar_modifier_t modifier);
+
+/** retrieve string name for orientation.
+ * @param orientation orientation encoding
+ * @returns the static string name for the specified orientation,
+ * or "UNKNOWN" if the orientation is not recognized
+ * @since 0.11
+ */
+extern const char *zbar_get_orientation_name(zbar_orientation_t orientation);
+
+/** parse a configuration string of the form "[symbology.]config[=value]".
+ * the config must match one of the recognized names.
+ * the symbology, if present, must match one of the recognized names.
+ * if symbology is unspecified, it will be set to 0.
+ * if value is unspecified it will be set to 1.
+ * @returns 0 if the config is parsed successfully, 1 otherwise
+ * @since 0.4
+ */
+extern int zbar_parse_config(const char *config_string,
+			     zbar_symbol_type_t *symbology,
+			     zbar_config_t *config, int *value);
+
+/** consistently compute fourcc values across architectures
+ * (adapted from v4l2 specification)
+ * @since 0.11
+ */
+#define zbar_fourcc(a, b, c, d)                       \
+    ((unsigned long)(a) | ((unsigned long)(b) << 8) | \
+     ((unsigned long)(c) << 16) | ((unsigned long)(d) << 24))
+
+/** parse a fourcc string into its encoded integer value.
+ * @since 0.11
+ */
+static inline unsigned long zbar_fourcc_parse(const char *format)
+{
+    unsigned long fourcc = 0;
+    if (format) {
+	int i;
+	for (i = 0; i < 4 && format[i]; i++)
+	    fourcc |= ((unsigned long)format[i]) << (i * 8);
+    }
+    return (fourcc);
+}
+
+/** @internal type unsafe error API (don't use) */
+extern int _zbar_error_spew(const void *object, int verbosity);
+extern const char *_zbar_error_string(const void *object, int verbosity);
+extern zbar_error_t _zbar_get_error_code(const void *object);
+
+/*@}*/
+
+struct zbar_symbol_s;
+typedef struct zbar_symbol_s zbar_symbol_t;
+
+struct zbar_symbol_set_s;
+typedef struct zbar_symbol_set_s zbar_symbol_set_t;
+
+/*------------------------------------------------------------*/
+/** @name Symbol interface
+ * decoded barcode symbol result object.  stores type, data, and image
+ * location of decoded symbol.  all memory is owned by the library
+ */
+/*@{*/
+
+/** @typedef zbar_symbol_t
+ * opaque decoded symbol object.
+ */
+
+/** symbol reference count manipulation.
+ * increment the reference count when you store a new reference to the
+ * symbol.  decrement when the reference is no longer used.  do not
+ * refer to the symbol once the count is decremented and the
+ * containing image has been recycled or destroyed.
+ * @note the containing image holds a reference to the symbol, so you
+ * only need to use this if you keep a symbol after the image has been
+ * destroyed or reused.
+ * @since 0.9
+ */
+extern void zbar_symbol_ref(const zbar_symbol_t *symbol, int refs);
+
+/** retrieve type of decoded symbol.
+ * @returns the symbol type
+ */
+extern zbar_symbol_type_t zbar_symbol_get_type(const zbar_symbol_t *symbol);
+
+/** retrieve symbology boolean config settings.
+ * @returns a bitmask indicating which configs were set for the detected
+ * symbology during decoding.
+ * @since 0.11
+ */
+extern unsigned int zbar_symbol_get_configs(const zbar_symbol_t *symbol);
+
+/** retrieve symbology modifier flag settings.
+ * @returns a bitmask indicating which characteristics were detected
+ * during decoding.
+ * @since 0.11
+ */
+extern unsigned int zbar_symbol_get_modifiers(const zbar_symbol_t *symbol);
+
+/** retrieve data decoded from symbol.
+ * @returns the data string
+ */
+extern const char *zbar_symbol_get_data(const zbar_symbol_t *symbol);
+
+/** retrieve length of binary data.
+ * @returns the length of the decoded data
+ */
+extern unsigned int zbar_symbol_get_data_length(const zbar_symbol_t *symbol);
+
+/** retrieve a symbol confidence metric.
+ * @returns an unscaled, relative quantity: larger values are better
+ * than smaller values, where "large" and "small" are application
+ * dependent.
+ * @note expect the exact definition of this quantity to change as the
+ * metric is refined.  currently, only the ordered relationship
+ * between two values is defined and will remain stable in the future
+ * @since 0.9
+ */
+extern int zbar_symbol_get_quality(const zbar_symbol_t *symbol);
+
+/** retrieve current cache count.  when the cache is enabled for the
+ * image_scanner this provides inter-frame reliability and redundancy
+ * information for video streams.
+ * @returns < 0 if symbol is still uncertain.
+ * @returns 0 if symbol is newly verified.
+ * @returns > 0 for duplicate symbols
+ */
+extern int zbar_symbol_get_count(const zbar_symbol_t *symbol);
+
+/** retrieve the number of points in the location polygon.  the
+ * location polygon defines the image area that the symbol was
+ * extracted from.
+ * @returns the number of points in the location polygon
+ * @note this is currently not a polygon, but the scan locations
+ * where the symbol was decoded
+ */
+extern unsigned zbar_symbol_get_loc_size(const zbar_symbol_t *symbol);
+
+/** retrieve location polygon x-coordinates.
+ * points are specified by 0-based index.
+ * @returns the x-coordinate for a point in the location polygon.
+ * @returns -1 if index is out of range
+ */
+extern int zbar_symbol_get_loc_x(const zbar_symbol_t *symbol, unsigned index);
+
+/** retrieve location polygon y-coordinates.
+ * points are specified by 0-based index.
+ * @returns the y-coordinate for a point in the location polygon.
+ * @returns -1 if index is out of range
+ */
+extern int zbar_symbol_get_loc_y(const zbar_symbol_t *symbol, unsigned index);
+
+/** retrieve general orientation of decoded symbol.
+ * @returns a coarse, axis-aligned indication of symbol orientation or
+ * ::ZBAR_ORIENT_UNKNOWN if unknown
+ * @since 0.11
+ */
+extern zbar_orientation_t
+zbar_symbol_get_orientation(const zbar_symbol_t *symbol);
+
+/** iterate the set to which this symbol belongs (there can be only one).
+ * @returns the next symbol in the set, or
+ * @returns NULL when no more results are available
+ */
+extern const zbar_symbol_t *zbar_symbol_next(const zbar_symbol_t *symbol);
+
+/** retrieve components of a composite result.
+ * @returns the symbol set containing the components
+ * @returns NULL if the symbol is already a physical symbol
+ * @since 0.10
+ */
+extern const zbar_symbol_set_t *
+zbar_symbol_get_components(const zbar_symbol_t *symbol);
+
+/** iterate components of a composite result.
+ * @returns the first physical component symbol of a composite result
+ * @returns NULL if the symbol is already a physical symbol
+ * @since 0.10
+ */
+extern const zbar_symbol_t *
+zbar_symbol_first_component(const zbar_symbol_t *symbol);
+
+/** print XML symbol element representation to user result buffer.
+ * @see http://zbar.sourceforge.net/2008/barcode.xsd for the schema.
+ * @param symbol is the symbol to print
+ * @param buffer is the inout result pointer, it will be reallocated
+ * with a larger size if necessary.
+ * @param buflen is inout length of the result buffer.
+ * @returns the buffer pointer
+ * @since 0.6
+ */
+extern char *zbar_symbol_xml(const zbar_symbol_t *symbol, char **buffer,
+			     unsigned *buflen);
+
+/*@}*/
+
+/*------------------------------------------------------------*/
+/** @name Symbol Set interface
+ * container for decoded result symbols associated with an image
+ * or a composite symbol.
+ * @since 0.10
+ */
+/*@{*/
+
+/** @typedef zbar_symbol_set_t
+ * opaque symbol iterator object.
+ * @since 0.10
+ */
+
+/** reference count manipulation.
+ * increment the reference count when you store a new reference.
+ * decrement when the reference is no longer used.  do not refer to
+ * the object any longer once references have been released.
+ * @since 0.10
+ */
+extern void zbar_symbol_set_ref(const zbar_symbol_set_t *symbols, int refs);
+
+/** retrieve set size.
+ * @returns the number of symbols in the set.
+ * @since 0.10
+ */
+extern int zbar_symbol_set_get_size(const zbar_symbol_set_t *symbols);
+
+/** set iterator.
+ * @returns the first decoded symbol result in a set
+ * @returns NULL if the set is empty
+ * @since 0.10
+ */
+extern const zbar_symbol_t *
+zbar_symbol_set_first_symbol(const zbar_symbol_set_t *symbols);
+
+/** raw result iterator.
+ * @returns the first decoded symbol result in a set, *before* filtering
+ * @returns NULL if the set is empty
+ * @since 0.11
+ */
+extern const zbar_symbol_t *
+zbar_symbol_set_first_unfiltered(const zbar_symbol_set_t *symbols);
+
+/*@}*/
+
+/*------------------------------------------------------------*/
+/** @name Image interface
+ * stores image data samples along with associated format and size
+ * metadata
+ */
+/*@{*/
+
+struct zbar_image_s;
+/**
+ * zbar_image_t: opaque image object.
+ */
+typedef struct zbar_image_s zbar_image_t;
+
+/** cleanup handler callback function.
+ * called to free sample data when an image is destroyed.
+ */
+typedef void(zbar_image_cleanup_handler_t)(zbar_image_t *image);
+
+/** data handler callback function.
+ * called when decoded symbol results are available for an image
+ */
+typedef void(zbar_image_data_handler_t)(zbar_image_t *image,
+					const void *userdata);
+
+/** new image constructor.
+ * @returns a new image object with uninitialized data and format.
+ * this image should be destroyed (using zbar_image_destroy()) as
+ * soon as the application is finished with it
+ */
+extern zbar_image_t *zbar_image_create(void);
+
+/** image destructor.  all images created by or returned to the
+ * application should be destroyed using this function.  when an image
+ * is destroyed, the associated data cleanup handler will be invoked
+ * if available
+ * @note make no assumptions about the image or the data buffer.
+ * they may not be destroyed/cleaned immediately if the library
+ * is still using them.  if necessary, use the cleanup handler hook
+ * to keep track of image data buffers
+ */
+extern void zbar_image_destroy(zbar_image_t *image);
+
+/** image reference count manipulation.
+ * increment the reference count when you store a new reference to the
+ * image.  decrement when the reference is no longer used.  do not
+ * refer to the image any longer once the count is decremented.
+ * zbar_image_ref(image, -1) is the same as zbar_image_destroy(image)
+ * @since 0.5
+ */
+extern void zbar_image_ref(zbar_image_t *image, int refs);
+
+/** image format conversion.  refer to the documentation for supported
+ * image formats
+ * @returns a @em new image with the sample data from the original image
+ * converted to the requested format.  the original image is
+ * unaffected.
+ * @note the converted image size may be rounded (up) due to format
+ * constraints
+ */
+extern zbar_image_t *zbar_image_convert(const zbar_image_t *image,
+					unsigned long format);
+
+/** image format conversion with crop/pad.
+ * if the requested size is larger than the image, the last row/column
+ * are duplicated to cover the difference.  if the requested size is
+ * smaller than the image, the extra rows/columns are dropped from the
+ * right/bottom.
+ * @returns a @em new image with the sample data from the original
+ * image converted to the requested format and size.
+ * @note the image is @em not scaled
+ * @see zbar_image_convert()
+ * @since 0.4
+ */
+extern zbar_image_t *zbar_image_convert_resize(const zbar_image_t *image,
+					       unsigned long format,
+					       unsigned width, unsigned height);
+
+/** retrieve the image format.
+ * @returns the fourcc describing the format of the image sample data
+ */
+extern unsigned long zbar_image_get_format(const zbar_image_t *image);
+
+/** retrieve a "sequence" (page/frame) number associated with this image.
+ * @since 0.6
+ */
+extern unsigned zbar_image_get_sequence(const zbar_image_t *image);
+
+/** retrieve the width of the image.
+ * @returns the width in sample columns
+ */
+extern unsigned zbar_image_get_width(const zbar_image_t *image);
+
+/** retrieve the height of the image.
+ * @returns the height in sample rows
+ */
+extern unsigned zbar_image_get_height(const zbar_image_t *image);
+
+/** retrieve both dimensions of the image.
+ * fills in the width and height in samples
+ */
+extern void zbar_image_get_size(const zbar_image_t *image, unsigned *width,
+				unsigned *height);
+
+/** retrieve the crop rectangle.
+ * fills in the image coordinates of the upper left corner and size
+ * of an axis-aligned rectangular area of the image that will be scanned.
+ * defaults to the full image
+ * @since 0.11
+ */
+extern void zbar_image_get_crop(const zbar_image_t *image, unsigned *x,
+				unsigned *y, unsigned *width, unsigned *height);
+
+/** return the image sample data.  the returned data buffer is only
+ * valid until zbar_image_destroy() is called
+ */
+extern const void *zbar_image_get_data(const zbar_image_t *image);
+
+/** return the size of image data.
+ * @since 0.6
+ */
+extern unsigned long zbar_image_get_data_length(const zbar_image_t *img);
+
+/** retrieve the decoded results.
+ * @returns the (possibly empty) set of decoded symbols
+ * @returns NULL if the image has not been scanned
+ * @since 0.10
+ */
+extern const zbar_symbol_set_t *
+zbar_image_get_symbols(const zbar_image_t *image);
+
+/** associate the specified symbol set with the image, replacing any
+ * existing results.  use NULL to release the current results from the
+ * image.
+ * @see zbar_image_scanner_recycle_image()
+ * @since 0.10
+ */
+extern void zbar_image_set_symbols(zbar_image_t *image,
+				   const zbar_symbol_set_t *symbols);
+
+/** image_scanner decode result iterator.
+ * @returns the first decoded symbol result for an image
+ * or NULL if no results are available
+ */
+extern const zbar_symbol_t *zbar_image_first_symbol(const zbar_image_t *image);
+
+/** specify the fourcc image format code for image sample data.
+ * refer to the documentation for supported formats.
+ * @note this does not convert the data!
+ * (see zbar_image_convert() for that)
+ */
+extern void zbar_image_set_format(zbar_image_t *image, unsigned long format);
+
+/** associate a "sequence" (page/frame) number with this image.
+ * @since 0.6
+ */
+extern void zbar_image_set_sequence(zbar_image_t *image, unsigned sequence_num);
+
+/** specify the pixel size of the image.
+ * @note this also resets the crop rectangle to the full image
+ * (0, 0, width, height)
+ * @note this does not affect the data!
+ */
+extern void zbar_image_set_size(zbar_image_t *image, unsigned width,
+				unsigned height);
+
+/** specify a rectangular region of the image to scan.
+ * the rectangle will be clipped to the image boundaries.
+ * defaults to the full image specified by zbar_image_set_size()
+ */
+extern void zbar_image_set_crop(zbar_image_t *image, unsigned x, unsigned y,
+				unsigned width, unsigned height);
+
+/** specify image sample data.  when image data is no longer needed by
+ * the library the specific data cleanup handler will be called
+ * (unless NULL)
+ * @note application image data will not be modified by the library
+ */
+extern void zbar_image_set_data(zbar_image_t *image, const void *data,
+				unsigned long data_byte_length,
+				zbar_image_cleanup_handler_t *cleanup_hndlr);
+
+/** built-in cleanup handler.
+ * passes the image data buffer to free()
+ */
+extern void zbar_image_free_data(zbar_image_t *image);
+
+/** associate user specified data value with an image.
+ * @since 0.5
+ */
+extern void zbar_image_set_userdata(zbar_image_t *image, void *userdata);
+
+/** return user specified data value associated with the image.
+ * @since 0.5
+ */
+extern void *zbar_image_get_userdata(const zbar_image_t *image);
+
+/** dump raw image data to a file for debug.
+ * the data will be prefixed with a 16 byte header consisting of:
+ *   - 4 bytes uint = 0x676d697a ("zimg")
+ *   - 4 bytes format fourcc
+ *   - 2 bytes width
+ *   - 2 bytes height
+ *   - 4 bytes size of following image data in bytes
+ * this header can be dumped w/eg:
+ * @verbatim
+       od -Ax -tx1z -N16 -w4 [file]
+@endverbatim
+ * for some formats the image can be displayed/converted using
+ * ImageMagick, eg:
+ * @verbatim
+       display -size 640x480+16 [-depth ?] [-sampling-factor ?x?] \
+           {GRAY,RGB,UYVY,YUV}:[file]
+@endverbatim
+ *
+ * @param image the image object to dump
+ * @param filebase base filename, appended with ".XXXX.zimg" where
+ * XXXX is the format fourcc
+ * @returns 0 on success or a system error code on failure
+ */
+extern int zbar_image_write(const zbar_image_t *image, const char *filebase);
+
+/** read back an image in the format written by zbar_image_write()
+ * @note TBD
+ */
+extern zbar_image_t *zbar_image_read(char *filename);
+
+/*@}*/
+
+/*------------------------------------------------------------*/
+/** @name Processor interface
+ * @anchor c-processor
+ * high-level self-contained image processor.
+ * processes video and images for barcodes, optionally displaying
+ * images to a library owned output window
+ */
+/*@{*/
+
+struct zbar_processor_s;
+/** opaque standalone processor object. */
+typedef struct zbar_processor_s zbar_processor_t;
+
+/** constructor.
+ * if threaded is set and threading is available the processor
+ * will spawn threads where appropriate to avoid blocking and
+ * improve responsiveness
+ */
+extern zbar_processor_t *zbar_processor_create(int threaded);
+
+/** destructor.  cleans up all resources associated with the processor
+ */
+extern void zbar_processor_destroy(zbar_processor_t *processor);
+
+/** (re)initialization.
+ * opens a video input device and/or prepares to display output
+ */
+extern int zbar_processor_init(zbar_processor_t *processor,
+			       const char *video_device, int enable_display);
+
+/** request a preferred size for the video image from the device.
+ * the request may be adjusted or completely ignored by the driver.
+ * @note must be called before zbar_processor_init()
+ * @since 0.6
+ */
+extern int zbar_processor_request_size(zbar_processor_t *processor,
+				       unsigned width, unsigned height);
+
+/** request a preferred video driver interface version for
+ * debug/testing.
+ * @note must be called before zbar_processor_init()
+ * @since 0.6
+ */
+extern int zbar_processor_request_interface(zbar_processor_t *processor,
+					    int version);
+
+/** request a preferred video I/O mode for debug/testing.  You will
+ * get errors if the driver does not support the specified mode.
+ * @verbatim
+    0 = auto-detect
+    1 = force I/O using read()
+    2 = force memory mapped I/O using mmap()
+    3 = force USERPTR I/O (v4l2 only)
+@endverbatim
+ * @note must be called before zbar_processor_init()
+ * @since 0.7
+ */
+extern int zbar_processor_request_iomode(zbar_processor_t *video, int iomode);
+
+/** force specific input and output formats for debug/testing.
+ * @note must be called before zbar_processor_init()
+ */
+extern int zbar_processor_force_format(zbar_processor_t *processor,
+				       unsigned long input_format,
+				       unsigned long output_format);
+
+/** setup result handler callback.
+ * the specified function will be called by the processor whenever
+ * new results are available from the video stream or a static image.
+ * pass a NULL value to disable callbacks.
+ * @param processor the object on which to set the handler.
+ * @param handler the function to call when new results are available.
+ * @param userdata is set as with zbar_processor_set_userdata().
+ * @returns the previously registered handler
+ */
+extern zbar_image_data_handler_t *
+zbar_processor_set_data_handler(zbar_processor_t *processor,
+				zbar_image_data_handler_t *handler,
+				const void *userdata);
+
+/** associate user specified data value with the processor.
+ * @since 0.6
+ */
+extern void zbar_processor_set_userdata(zbar_processor_t *processor,
+					void *userdata);
+
+/** return user specified data value associated with the processor.
+ * @since 0.6
+ */
+extern void *zbar_processor_get_userdata(const zbar_processor_t *processor);
+
+/** set config for indicated symbology (0 for all) to specified value.
+ * @returns 0 for success, non-0 for failure (config does not apply to
+ * specified symbology, or value out of range)
+ * @see zbar_decoder_set_config()
+ * @since 0.4
+ */
+extern int zbar_processor_set_config(zbar_processor_t *processor,
+				     zbar_symbol_type_t symbology,
+				     zbar_config_t config, int value);
+
+/** set video control value
+ * @returns 0 for success, non-0 for failure
+ * @since 0.20
+ * @see zbar_video_set_control()
+ */
+extern int zbar_processor_set_control(zbar_processor_t *processor,
+				      const char *control_name, int value);
+
+/** get video control value
+ * @returns 0 for success, non-0 for failure
+ * @since 0.20
+ * @see zbar_video_get_control()
+ */
+extern int zbar_processor_get_control(zbar_processor_t *processor,
+				      const char *control_name, int *value);
+
+/** parse configuration string using zbar_parse_config()
+ * and apply to processor using zbar_processor_set_config().
+ * @returns 0 for success, non-0 for failure
+ * @see zbar_parse_config()
+ * @see zbar_processor_set_config()
+ * @since 0.4
+ */
+static inline int zbar_processor_parse_config(zbar_processor_t *processor,
+					      const char *config_string)
+{
+    zbar_symbol_type_t sym;
+    zbar_config_t cfg;
+    int val;
+    return (zbar_parse_config(config_string, &sym, &cfg, &val) ||
+	    zbar_processor_set_config(processor, sym, cfg, val));
+}
+
+/** retrieve the current state of the output window.
+ * @returns 1 if the output window is currently displayed, 0 if not.
+ * @returns -1 if an error occurs
+ */
+extern int zbar_processor_is_visible(zbar_processor_t *processor);
+
+/** show or hide the display window owned by the library.
+ * the size will be adjusted to the input size
+ */
+extern int zbar_processor_set_visible(zbar_processor_t *processor, int visible);
+
+/** control the processor in free running video mode.
+ * only works if video input is initialized. if threading is in use,
+ * scanning will occur in the background, otherwise this is only
+ * useful wrapping calls to zbar_processor_user_wait(). if the
+ * library output window is visible, video display will be enabled.
+ */
+extern int zbar_processor_set_active(zbar_processor_t *processor, int active);
+
+/** retrieve decode results for last scanned image/frame.
+ * @returns the symbol set result container or NULL if no results are
+ * available
+ * @note the returned symbol set has its reference count incremented;
+ * ensure that the count is decremented after use
+ * @since 0.10
+ */
+extern const zbar_symbol_set_t *
+zbar_processor_get_results(const zbar_processor_t *processor);
+
+/** wait for input to the display window from the user
+ * (via mouse or keyboard).
+ * @returns >0 when input is received, 0 if timeout ms expired
+ * with no input or -1 in case of an error
+ */
+extern int zbar_processor_user_wait(zbar_processor_t *processor, int timeout);
+
+/** process from the video stream until a result is available,
+ * or the timeout (in milliseconds) expires.
+ * specify a timeout of -1 to scan indefinitely
+ * (zbar_processor_set_active() may still be used to abort the scan
+ * from another thread).
+ * if the library window is visible, video display will be enabled.
+ * @note that multiple results may still be returned (despite the
+ * name).
+ * @returns >0 if symbols were successfully decoded,
+ * 0 if no symbols were found (ie, the timeout expired)
+ * or -1 if an error occurs
+ */
+extern int zbar_process_one(zbar_processor_t *processor, int timeout);
+
+/** process the provided image for barcodes.
+ * if the library window is visible, the image will be displayed.
+ * @returns >0 if symbols were successfully decoded,
+ * 0 if no symbols were found or -1 if an error occurs
+ */
+extern int zbar_process_image(zbar_processor_t *processor, zbar_image_t *image);
+
+/** enable dbus IPC API.
+ * @returns 0 successful
+ */
+int zbar_processor_request_dbus(zbar_processor_t *proc, int req_dbus_enabled);
+
+/** display detail for last processor error to stderr.
+ * @returns a non-zero value suitable for passing to exit()
+ */
+static inline int zbar_processor_error_spew(const zbar_processor_t *processor,
+					    int verbosity)
+{
+    return (_zbar_error_spew(processor, verbosity));
+}
+
+/** retrieve the detail string for the last processor error. */
+static inline const char *
+zbar_processor_error_string(const zbar_processor_t *processor, int verbosity)
+{
+    return (_zbar_error_string(processor, verbosity));
+}
+
+/** retrieve the type code for the last processor error. */
+static inline zbar_error_t
+zbar_processor_get_error_code(const zbar_processor_t *processor)
+{
+    return (_zbar_get_error_code(processor));
+}
+
+/*@}*/
+
+/*------------------------------------------------------------*/
+/** @name Video interface
+ * @anchor c-video
+ * mid-level video source abstraction.
+ * captures images from a video device
+ */
+/*@{*/
+
+struct zbar_video_s;
+/** opaque video object. */
+typedef struct zbar_video_s zbar_video_t;
+
+/** constructor. */
+extern zbar_video_t *zbar_video_create(void);
+
+/** destructor. */
+extern void zbar_video_destroy(zbar_video_t *video);
+
+/** open and probe a video device.
+ * the device specified by platform specific unique name
+ * (v4l device node path in *nix eg "/dev/video",
+ *  DirectShow DevicePath property in windows).
+ * @returns 0 if successful or -1 if an error occurs
+ */
+extern int zbar_video_open(zbar_video_t *video, const char *device);
+
+/** retrieve file descriptor associated with open *nix video device
+ * useful for using select()/poll() to tell when new images are
+ * available (NB v4l2 only!!).
+ * @returns the file descriptor or -1 if the video device is not open
+ * or the driver only supports v4l1
+ */
+extern int zbar_video_get_fd(const zbar_video_t *video);
+
+/** request a preferred size for the video image from the device.
+ * the request may be adjusted or completely ignored by the driver.
+ * @returns 0 if successful or -1 if the video device is already
+ * initialized
+ * @since 0.6
+ */
+extern int zbar_video_request_size(zbar_video_t *video, unsigned width,
+				   unsigned height);
+
+/** request a preferred driver interface version for debug/testing.
+ * @note must be called before zbar_video_open()
+ * @since 0.6
+ */
+extern int zbar_video_request_interface(zbar_video_t *video, int version);
+
+/** request a preferred I/O mode for debug/testing.  You will get
+ * errors if the driver does not support the specified mode.
+ * @verbatim
+    0 = auto-detect
+    1 = force I/O using read()
+    2 = force memory mapped I/O using mmap()
+    3 = force USERPTR I/O (v4l2 only)
+@endverbatim
+ * @note must be called before zbar_video_open()
+ * @since 0.7
+ */
+extern int zbar_video_request_iomode(zbar_video_t *video, int iomode);
+
+/** retrieve current output image width.
+ * @returns the width or 0 if the video device is not open
+ */
+extern int zbar_video_get_width(const zbar_video_t *video);
+
+/** retrieve current output image height.
+ * @returns the height or 0 if the video device is not open
+ */
+extern int zbar_video_get_height(const zbar_video_t *video);
+
+/** initialize video using a specific format for debug.
+ * use zbar_negotiate_format() to automatically select and initialize
+ * the best available format
+ */
+extern int zbar_video_init(zbar_video_t *video, unsigned long format);
+
+/** start/stop video capture.
+ * all buffered images are retired when capture is disabled.
+ * @returns 0 if successful or -1 if an error occurs
+ */
+extern int zbar_video_enable(zbar_video_t *video, int enable);
+
+/** retrieve next captured image.  blocks until an image is available.
+ * @returns NULL if video is not enabled or an error occurs
+ */
+extern zbar_image_t *zbar_video_next_image(zbar_video_t *video);
+
+/** set video control value (integer).
+ * @returns 0 for success, non-0 for failure
+ * @since 0.20
+ * @see zbar_processor_set_control()
+ */
+extern int zbar_video_set_control(zbar_video_t *video, const char *control_name,
+				  int value);
+
+/** get video control value (integer).
+ * @returns 0 for success, non-0 for failure
+ * @since 0.20
+ * @see zbar_processor_get_control()
+ */
+extern int zbar_video_get_control(zbar_video_t *video, const char *control_name,
+				  int *value);
+
+/** get available controls from video source
+ * @returns 0 for success, non-0 for failure
+ * @since 0.20
+ */
+extern struct video_controls_s *
+zbar_video_get_controls(const zbar_video_t *video, int index);
+
+/** get available video resolutions from video source
+ * @returns 0 for success, non-0 for failure
+ * @since 0.22
+ */
+extern struct video_resolution_s *
+zbar_video_get_resolutions(const zbar_video_t *vdo, int index);
+
+/** display detail for last video error to stderr.
+ * @returns a non-zero value suitable for passing to exit()
+ */
+static inline int zbar_video_error_spew(const zbar_video_t *video,
+					int verbosity)
+{
+    return (_zbar_error_spew(video, verbosity));
+}
+
+/** retrieve the detail string for the last video error. */
+static inline const char *zbar_video_error_string(const zbar_video_t *video,
+						  int verbosity)
+{
+    return (_zbar_error_string(video, verbosity));
+}
+
+/** retrieve the type code for the last video error. */
+static inline zbar_error_t zbar_video_get_error_code(const zbar_video_t *video)
+{
+    return (_zbar_get_error_code(video));
+}
+
+/*@}*/
+
+/*------------------------------------------------------------*/
+/** @name Window interface
+ * @anchor c-window
+ * mid-level output window abstraction.
+ * displays images to user-specified platform specific output window
+ */
+/*@{*/
+
+struct zbar_window_s;
+/** opaque window object. */
+typedef struct zbar_window_s zbar_window_t;
+
+/** constructor. */
+extern zbar_window_t *zbar_window_create(void);
+
+/** destructor. */
+extern void zbar_window_destroy(zbar_window_t *window);
+
+/** associate reader with an existing platform window.
+ * This can be any "Drawable" for X Windows or a "HWND" for windows.
+ * input images will be scaled into the output window.
+ * pass NULL to detach from the resource, further input will be
+ * ignored
+ */
+extern int zbar_window_attach(zbar_window_t *window, void *x11_display_w32_hwnd,
+			      unsigned long x11_drawable);
+
+/** control content level of the reader overlay.
+ * the overlay displays graphical data for informational or debug
+ * purposes.  higher values increase the level of annotation (possibly
+ * decreasing performance). @verbatim
+    0 = disable overlay
+    1 = outline decoded symbols (default)
+    2 = also track and display input frame rate
+@endverbatim
+ */
+extern void zbar_window_set_overlay(zbar_window_t *window, int level);
+
+/** retrieve current content level of reader overlay.
+ * @see zbar_window_set_overlay()
+ * @since 0.10
+ */
+extern int zbar_window_get_overlay(const zbar_window_t *window);
+
+/** draw a new image into the output window. */
+extern int zbar_window_draw(zbar_window_t *window, zbar_image_t *image);
+
+/** redraw the last image (exposure handler). */
+extern int zbar_window_redraw(zbar_window_t *window);
+
+/** resize the image window (reconfigure handler).
+ * this does @em not update the contents of the window
+ * @since 0.3, changed in 0.4 to not redraw window
+ */
+extern int zbar_window_resize(zbar_window_t *window, unsigned width,
+			      unsigned height);
+
+/** display detail for last window error to stderr.
+ * @returns a non-zero value suitable for passing to exit()
+ */
+static inline int zbar_window_error_spew(const zbar_window_t *window,
+					 int verbosity)
+{
+    return (_zbar_error_spew(window, verbosity));
+}
+
+/** retrieve the detail string for the last window error. */
+static inline const char *zbar_window_error_string(const zbar_window_t *window,
+						   int verbosity)
+{
+    return (_zbar_error_string(window, verbosity));
+}
+
+/** retrieve the type code for the last window error. */
+static inline zbar_error_t
+zbar_window_get_error_code(const zbar_window_t *window)
+{
+    return (_zbar_get_error_code(window));
+}
+
+/** select a compatible format between video input and output window.
+ * the selection algorithm attempts to use a format shared by
+ * video input and window output which is also most useful for
+ * barcode scanning.  if a format conversion is necessary, it will
+ * heuristically attempt to minimize the cost of the conversion
+ */
+extern int zbar_negotiate_format(zbar_video_t *video, zbar_window_t *window);
+
+/*@}*/
+
+/*------------------------------------------------------------*/
+/** @name Image Scanner interface
+ * @anchor c-imagescanner
+ * mid-level image scanner interface.
+ * reads barcodes from 2-D images
+ */
+/*@{*/
+
+struct zbar_image_scanner_s;
+/** opaque image scanner object. */
+typedef struct zbar_image_scanner_s zbar_image_scanner_t;
+
+/** constructor. */
+extern zbar_image_scanner_t *zbar_image_scanner_create(void);
+
+/** destructor. */
+extern void zbar_image_scanner_destroy(zbar_image_scanner_t *scanner);
+
+/** setup result handler callback.
+ * the specified function will be called by the scanner whenever
+ * new results are available from a decoded image.
+ * pass a NULL value to disable callbacks.
+ * @returns the previously registered handler
+ */
+extern zbar_image_data_handler_t *
+zbar_image_scanner_set_data_handler(zbar_image_scanner_t *scanner,
+				    zbar_image_data_handler_t *handler,
+				    const void *userdata);
+
+/** request sending decoded codes via D-Bus
+ * @see zbar_processor_parse_config()
+ * @since 0.21
+ */
+extern int zbar_image_scanner_request_dbus(zbar_image_scanner_t *scanner,
+					   int req_dbus_enabled);
+
+/** set config for indicated symbology (0 for all) to specified value.
+ * @returns 0 for success, non-0 for failure (config does not apply to
+ * specified symbology, or value out of range)
+ * @see zbar_decoder_set_config()
+ * @since 0.4
+ */
+extern int zbar_image_scanner_set_config(zbar_image_scanner_t *scanner,
+					 zbar_symbol_type_t symbology,
+					 zbar_config_t config, int value);
+
+/** get config for indicated symbology
+ * @returns 0 for success, non-0 for failure (config does not apply to
+ * specified symbology, or value out of range). On success, *value is filled.
+ * @since 0.22
+ */
+extern int zbar_image_scanner_get_config(zbar_image_scanner_t *scanner,
+					 zbar_symbol_type_t symbology,
+					 zbar_config_t config, int *value);
+
+/** parse configuration string using zbar_parse_config()
+ * and apply to image scanner using zbar_image_scanner_set_config().
+ * @returns 0 for success, non-0 for failure
+ * @see zbar_parse_config()
+ * @see zbar_image_scanner_set_config()
+ * @since 0.4
+ */
+static inline int zbar_image_scanner_parse_config(zbar_image_scanner_t *scanner,
+						  const char *config_string)
+{
+    zbar_symbol_type_t sym;
+    zbar_config_t cfg;
+    int val;
+    return (zbar_parse_config(config_string, &sym, &cfg, &val) ||
+	    zbar_image_scanner_set_config(scanner, sym, cfg, val));
+}
+
+/** enable or disable the inter-image result cache (default disabled).
+ * mostly useful for scanning video frames, the cache filters
+ * duplicate results from consecutive images, while adding some
+ * consistency checking and hysteresis to the results.
+ * this interface also clears the cache
+ */
+extern void zbar_image_scanner_enable_cache(zbar_image_scanner_t *scanner,
+					    int enable);
+
+/** remove any previously decoded results from the image scanner and the
+ * specified image.  somewhat more efficient version of
+ * zbar_image_set_symbols(image, NULL) which may retain memory for
+ * subsequent decodes
+ * @since 0.10
+ */
+extern void zbar_image_scanner_recycle_image(zbar_image_scanner_t *scanner,
+					     zbar_image_t *image);
+
+/** retrieve decode results for last scanned image.
+ * @returns the symbol set result container or NULL if no results are
+ * available
+ * @note the symbol set does not have its reference count adjusted;
+ * ensure that the count is incremented if the results may be kept
+ * after the next image is scanned
+ * @since 0.10
+ */
+extern const zbar_symbol_set_t *
+zbar_image_scanner_get_results(const zbar_image_scanner_t *scanner);
+
+/** scan for symbols in provided image.  The image format must be
+ * "Y800" or "GRAY".
+ * @returns >0 if symbols were successfully decoded from the image,
+ * 0 if no symbols were found or -1 if an error occurs
+ * @see zbar_image_convert()
+ * @since 0.9 - changed to only accept grayscale images
+ */
+extern int zbar_scan_image(zbar_image_scanner_t *scanner, zbar_image_t *image);
+
+/*@}*/
+
+/*------------------------------------------------------------*/
+/** @name Decoder interface
+ * @anchor c-decoder
+ * low-level bar width stream decoder interface.
+ * identifies symbols and extracts encoded data
+ */
+/*@{*/
+
+struct zbar_decoder_s;
+/** opaque decoder object. */
+typedef struct zbar_decoder_s zbar_decoder_t;
+
+/** decoder data handler callback function.
+ * called by decoder when new data has just been decoded
+ */
+typedef void(zbar_decoder_handler_t)(zbar_decoder_t *decoder);
+
+/** constructor. */
+extern zbar_decoder_t *zbar_decoder_create(void);
+
+/** destructor. */
+extern void zbar_decoder_destroy(zbar_decoder_t *decoder);
+
+/** set config for indicated symbology (0 for all) to specified value.
+ * @returns 0 for success, non-0 for failure (config does not apply to
+ * specified symbology, or value out of range)
+ * @since 0.4
+ */
+extern int zbar_decoder_set_config(zbar_decoder_t *decoder,
+				   zbar_symbol_type_t symbology,
+				   zbar_config_t config, int value);
+
+/** get config for indicated symbology
+ * @returns 0 for success, non-0 for failure (config does not apply to
+ * specified symbology, or value out of range). On success, *value is filled.
+ * @since 0.22
+ */
+extern int zbar_decoder_get_config(zbar_decoder_t *decoder,
+				   zbar_symbol_type_t symbology,
+				   zbar_config_t config, int *value);
+
+/** parse configuration string using zbar_parse_config()
+ * and apply to decoder using zbar_decoder_set_config().
+ * @returns 0 for success, non-0 for failure
+ * @see zbar_parse_config()
+ * @see zbar_decoder_set_config()
+ * @since 0.4
+ */
+static inline int zbar_decoder_parse_config(zbar_decoder_t *decoder,
+					    const char *config_string)
+{
+    zbar_symbol_type_t sym;
+    zbar_config_t cfg;
+    int val;
+    return (zbar_parse_config(config_string, &sym, &cfg, &val) ||
+	    zbar_decoder_set_config(decoder, sym, cfg, val));
+}
+
+/** retrieve symbology boolean config settings.
+ * @returns a bitmask indicating which configs are currently set for the
+ * specified symbology.
+ * @since 0.11
+ */
+extern unsigned int zbar_decoder_get_configs(const zbar_decoder_t *decoder,
+					     zbar_symbol_type_t symbology);
+
+/** clear all decoder state.
+ * any partial symbols are flushed
+ */
+extern void zbar_decoder_reset(zbar_decoder_t *decoder);
+
+/** mark start of a new scan pass.
+ * clears any intra-symbol state and resets color to ::ZBAR_SPACE.
+ * any partially decoded symbol state is retained
+ */
+extern void zbar_decoder_new_scan(zbar_decoder_t *decoder);
+
+/** process next bar/space width from input stream.
+ * the width is in arbitrary relative units.  first value of a scan
+ * is ::ZBAR_SPACE width, alternating from there.
+ * @returns appropriate symbol type if width completes
+ * decode of a symbol (data is available for retrieval)
+ * @returns ::ZBAR_PARTIAL as a hint if part of a symbol was decoded
+ * @returns ::ZBAR_NONE (0) if no new symbol data is available
+ */
+extern zbar_symbol_type_t zbar_decode_width(zbar_decoder_t *decoder,
+					    unsigned width);
+
+/** retrieve color of @em next element passed to
+ * zbar_decode_width(). */
+extern zbar_color_t zbar_decoder_get_color(const zbar_decoder_t *decoder);
+
+/** retrieve last decoded data.
+ * @returns the data string or NULL if no new data available.
+ * the returned data buffer is owned by library, contents are only
+ * valid between non-0 return from zbar_decode_width and next library
+ * call
+ */
+extern const char *zbar_decoder_get_data(const zbar_decoder_t *decoder);
+
+/** retrieve length of binary data.
+ * @returns the length of the decoded data or 0 if no new data
+ * available.
+ */
+extern unsigned int zbar_decoder_get_data_length(const zbar_decoder_t *decoder);
+
+/** retrieve last decoded symbol type.
+ * @returns the type or ::ZBAR_NONE if no new data available
+ */
+extern zbar_symbol_type_t zbar_decoder_get_type(const zbar_decoder_t *decoder);
+
+/** retrieve modifier flags for the last decoded symbol.
+ * @returns a bitmask indicating which characteristics were detected
+ * during decoding.
+ * @since 0.11
+ */
+extern unsigned int zbar_decoder_get_modifiers(const zbar_decoder_t *decoder);
+
+/** retrieve last decode direction.
+ * @returns 1 for forward and -1 for reverse
+ * @returns 0 if the decode direction is unknown or does not apply
+ * @since 0.11
+ */
+extern int zbar_decoder_get_direction(const zbar_decoder_t *decoder);
+
+/** setup data handler callback.
+ * the registered function will be called by the decoder
+ * just before zbar_decode_width() returns a non-zero value.
+ * pass a NULL value to disable callbacks.
+ * @returns the previously registered handler
+ */
+extern zbar_decoder_handler_t *
+zbar_decoder_set_handler(zbar_decoder_t *decoder,
+			 zbar_decoder_handler_t *handler);
+
+/** associate user specified data value with the decoder. */
+extern void zbar_decoder_set_userdata(zbar_decoder_t *decoder, void *userdata);
+
+/** return user specified data value associated with the decoder. */
+extern void *zbar_decoder_get_userdata(const zbar_decoder_t *decoder);
+
+/*@}*/
+
+/*------------------------------------------------------------*/
+/** @name Scanner interface
+ * @anchor c-scanner
+ * low-level linear intensity sample stream scanner interface.
+ * identifies "bar" edges and measures width between them.
+ * optionally passes to bar width decoder
+ */
+/*@{*/
+
+struct zbar_scanner_s;
+/** opaque scanner object. */
+typedef struct zbar_scanner_s zbar_scanner_t;
+
+/** constructor.
+ * if decoder is non-NULL it will be attached to scanner
+ * and called automatically at each new edge
+ * current color is initialized to ::ZBAR_SPACE
+ * (so an initial BAR->SPACE transition may be discarded)
+ */
+extern zbar_scanner_t *zbar_scanner_create(zbar_decoder_t *decoder);
+
+/** destructor. */
+extern void zbar_scanner_destroy(zbar_scanner_t *scanner);
+
+/** clear all scanner state.
+ * also resets an associated decoder
+ */
+extern zbar_symbol_type_t zbar_scanner_reset(zbar_scanner_t *scanner);
+
+/** mark start of a new scan pass. resets color to ::ZBAR_SPACE.
+ * also updates an associated decoder.
+ * @returns any decode results flushed from the pipeline
+ * @note when not using callback handlers, the return value should
+ * be checked the same as zbar_scan_y()
+ * @note call zbar_scanner_flush() at least twice before calling this
+ * method to ensure no decode results are lost
+ */
+extern zbar_symbol_type_t zbar_scanner_new_scan(zbar_scanner_t *scanner);
+
+/** flush scanner processing pipeline.
+ * forces current scanner position to be a scan boundary.
+ * call multiple times (max 3) to completely flush decoder.
+ * @returns any decode/scan results flushed from the pipeline
+ * @note when not using callback handlers, the return value should
+ * be checked the same as zbar_scan_y()
+ * @since 0.9
+ */
+extern zbar_symbol_type_t zbar_scanner_flush(zbar_scanner_t *scanner);
+
+/** process next sample intensity value.
+ * intensity (y) is in arbitrary relative units.
+ * @returns result of zbar_decode_width() if a decoder is attached,
+ * otherwise @returns (::ZBAR_PARTIAL) when new edge is detected
+ * or 0 (::ZBAR_NONE) if no new edge is detected
+ */
+extern zbar_symbol_type_t zbar_scan_y(zbar_scanner_t *scanner, int y);
+
+/** process next sample from RGB (or BGR) triple. */
+static inline zbar_symbol_type_t zbar_scan_rgb24(zbar_scanner_t *scanner,
+						 unsigned char *rgb)
+{
+    return (zbar_scan_y(scanner, rgb[0] + rgb[1] + rgb[2]));
+}
+
+/** retrieve last scanned width. */
+extern unsigned zbar_scanner_get_width(const zbar_scanner_t *scanner);
+
+/** retrieve sample position of last edge.
+ * @since 0.10
+ */
+extern unsigned zbar_scanner_get_edge(const zbar_scanner_t *scn,
+				      unsigned offset, int prec);
+
+/** retrieve last scanned color. */
+extern zbar_color_t zbar_scanner_get_color(const zbar_scanner_t *scanner);
+
+/*@}*/
+
+#ifdef __cplusplus
+}
+}
+
+#include "zbar/Decoder.h"
+#include "zbar/Exception.h"
+#include "zbar/Image.h"
+#include "zbar/ImageScanner.h"
+#include "zbar/Processor.h"
+#include "zbar/Scanner.h"
+#include "zbar/Symbol.h"
+#include "zbar/Video.h"
+#include "zbar/Window.h"
+#endif
+
+#endif