Contents
The main LibRaw object (class) is created either without parameters or with flags determining the object behavior.
#include "libraw/libraw.h"
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LibRaw ImageProcessor(unsigned int flags=0);
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Flags (several flags are combined via operator |, i.e., bitwise OR):
Three groups of methods are used for image processing
The results of processing are placed in the imgdata field of type libraw_data_t; the same data set contains fields that control the postprocessing and output.
All LibRaw API functions return an integer number in accordance with the return code convention. Please read the descriptions of this convention and LibRaw behavior in cases of fatal errors.
Opens a datastream with RAW data, reads metadata (EXIF) from it, and fills the following structures:
The function returns an integer number in accordance with the return code convention: positive if any system call has returned an error, negative (from the LibRaw error list) if there has been an error situation within LibRaw.
Before file opening, recycle() is always called; hence, if several images are processed in the batch mode, there is no need to call recycle() at the end of each processing cycle.
Input data: pointer to object, derived from LibRaw_abstract_datastream class. This object should be initialized and ready to read. This object should be destroyed in calling application after use.
Creates an LibRaw_file_datastream object, calls open_datastream(). If succeed, sets internal flag which signals to destroy internal datastream object on recycle(). On failure, just created file_datastream destroyed immediately.
Second optional parameter bigfile_size controls background I/O interface used for file operations. For files smaller than bigfile_size the LibRaw_file_datastream will be used and the LibRaw_bigfile_datastream otherwise.
The function returns an integer number in accordance with the return code convention: positive if any system call has returned an error, negative (from the LibRaw error list) if there has been an error situation within LibRaw.
Created an LibRaw_buffer_datastream object, calls open_datastream(). If succeed, sets internal flag which signals to destroy internal datastream object on recycle(). On failure, just created file_datastream destroyed immediately.
The function returns an integer number in accordance with the return code convention: positive if any system call has returned an error, negative (from the LibRaw error list) if there has been an error situation within LibRaw.
Unpacks the RAW files of the image, calculates the black level (not for all formats). The results are placed in imgdata.image.
Data reading is sometimes (not frequently) affected by settings made in imgdata.params (libraw_output_params_t); see API notes for details.
The function returns an integer number in accordance with the return code convention: positive if any system call has returned an error, negative (from the LibRaw error list) if there has been an error situation within LibRaw.
Reads (or unpacks) the image preview (thumbnail), placing the result into the imgdata.thumbnail.thumb buffer.
JPEG previews are placed into this buffer without any changes (with the header etc.). Other preview
formats are placed into the buffer in the form of the unpacked bitmap image (three components, 8 bits per component).
The thumbnail format is written to the imgdata.thumbnail.tformat field; for the possible values, see
description of constants and data structures.
The function returns an integer number in accordance with the return code convention: positive if any system call has returned an error, negative (from the LibRaw error list) if there has been an error situation within LibRaw.
Returns string representation of LibRaw version in MAJOR.MINOR.PATCH-Status format (i.e. 0.6.0-Alpha2 or 0.6.1-Release).
Returns integer representation of LibRaw version. During LibRaw development, the version number is always increase .
Macro for version check in caller applications. Returns 'true' if current library version is greater or equal to set in macro parameters. This macro executes at runtime (not at compile time) and may be used for checking version of dynamically loaded LibRaw (from DLL/shared library).
Returns count of cameras supported.
Returns list of supported cameras. Latest item of list is set to NULL (for easy printing).
(Only if LibRaw was built with RawSpeed support).
Loads XML file with RawSpeed camera description data (cameras.xml) specified by path_to_cameras_xml. Returns 0 on success, nonzero on error.
The function fills libraw_decoder_info_t structure by passed pointer with current raw decoder data.
The function returns an integer number in accordance with the return code convention: positive if any system call has returned an error, negative (from the LibRaw error list) if there has been an error situation within LibRaw.
Returns function name of file unpacking function. Intended only for LibRaw test suite designers to use in test coverage evaluation.
This call sets internal fast cancel flags. If set, current Raw decoder will be terminated ASAP. This call is useful if you need to cancel all LibRaw decoders in multithreaded program (e.g. for fast program termination or just for cancel current processing).
This call clears internal fast cancel flags, so (early) terminated LibRaw decoder may work again.
This call returns pixel color (color component number) in bayer patter at row,col. The returned value is in 0..3 range for 4-component Bayer (RGBG2, CMYG and so on) and in 0..2 range for 3-color data.
This call returns color data type found in opened file:
This call returns count of non-fatal data errors (out of range, etc) occured in unpack() stage.
This call will subtract black level values from RAW data (for suitable RAW data). colordata.data_maximum and colordata.maximum and black level data (colordata.black and colordata.cblack) will be adjusted too.
This call should be used if you postprocess RAW data by your own code. LibRaw postprocessing functions will call subtract_black() by oneself.
The function returns an integer number in accordance with the return code convention: positive if any system call has returned an error, negative (from the LibRaw error list) if there has been an error situation within LibRaw.
int LibRaw::is_sraw();
int LibRaw::is_nikon_sraw();
int LibRaw::sraw_midpoint()
This call closes input datastream with associated data buffer and unblocks opened file.
Frees the allocated data of LibRaw instance, enabling one to process the next file using the same processor. Repeated calls of recycle() are quite possible and do not conflict with anything.
Destructor, which consists in calling recycle().
Converts progress stage code to description string (in English).
Analog of strerror(3) function: outputs the text descriptions of LibRaw error codes (in English).
In process of RAW conversion LibRaw can call user-setted callback. This callback can be used for:
Also, work of the library may cause two types of exceptional situations that require notification of the calling application:
An application may set its own callbacks that will be called in the cases mentioned above to notify the user (or the calling program).
typedef int (*progress_callback)(void *callback_data,enum LibRaw_progress stage, int iteration, int expected);
void LibRaw::set_progress_handler(progress_callback func,void *callback_data);
LibRaw user can set own callback which will be called 10-50 times during RAW postprocessing by dcraw_process().
This callback may terminate current image processing by returning of non-zero value. In such case all processing will be cancelled immediately and all resources will be returned to system by recycle() call. Current call of dcraw_process() will return error code LIBRAW_CANCELLED_BY_CALLBACK.
Callback parameters:
If LibRaw compiled with OpenMP support, iteration parameter may not always increase within one stage. Out of order callback calls are possible.
Callback code sample:
int my_progress_callback(void *data,enum LibRaw_progress p,int iteration, int expected)
{
char *passed_string = (char *data);
printf("Callback: %s pass %d of %d, data passed: %s\n",libraw_strprogress(p),iteration,expected,passed_string);
if(timeout || key_pressed )
return 1; // cancel processing immediately
else
return 0; // can continue
}
typedef void (*exif_parser_callback) (void *context, int tag, int type, int len,unsigned int ord, void *ifp);
void LibRaw::set_exifparser_handler( exif_parser_callback cb,void *context);
Callback to be called on each parsed EXIF/Makernotes tag with parameters:
typedef void (* memory_callback)(void *callback_data,const char *file, const char *where);
void LibRaw::set_memerror_handler(memory_callback func,void *callback_data);
The user may set his or her own function called in the case of memory shortage. It is a void function receiving two string parameters:
The callback function is intended for information purposes: it notifies the user or the program code that processing is impossible.
If the user does not set his or her own handler, the standard one (output of error message in stderr) will be used.
One can set the null handler by passing NULL to set_memerror_handler; then no notifier function will be called. The same effect can be achieved by creating a LibRaw object with the LIBRAW_OPTIONS_NO_MEMERR_CALLBACK flag in the contructor.
In the case of memory shortage, processing of the current file is terminated and a notifier is called; all
allocated resources are freed, and recycle() is performed. The current call will return
LIBRAW_UNSUFFICIENT_MEMORY.
At an attempt to continue data processing, all subsequent calls will return LIBRAW_OUT_OF_ORDER_CALL.
Processing of a new file may be started in the usual way, by calling LibRaw::open_file().
typedef void (*data_callback)(void *callback_data,const char *file, const int offset);
void LibRaw::set_dataerror_handler(data_callback func, void *callback_data);
The user can define his or her own function to be called in the case of error in the input data. It is a void function receiving two parameters:
The callback function is intended for information purposes: it notifies the user or the program code that processing is impossible.
If the user does not set his or her own handler, the standard one (output of error message in stderr) will be used.
One can set the null handler by passing NULL to set_memerror_handler; then no notifier function will be called. The same effect can be achieved by creating a LibRaw object with the LIBRAW_OPTIONS_NO_DATAERR_CALLBACK flag in the contructor.
In the case of error in the input data, processing of the current file is terminated and a notifier is called; all
allocated resources are freed, and recycle() is performed. The current call will return
LIBRAW_IO_ERROR.
At an attempt to continue data processing, all subsequent calls will return LIBRAW_OUT_OF_ORDER_CALL.
Processing of a new file may be started in the usual way, by calling LibRaw::open_file().
Instead of writing one's own Bayer pattern postprocessing, one can use the dcraw functions, which are called after the calls of open_file() + unpack() /+ unpack_thumb()/
Virtually all parameters that can be set through the dcraw command line are specified by assigning values to fields of the LibRaw::imgdata.params structure. The type of this structure is libraw_output_params_t; all fields are listed and described in sufficient detail in the description of data structures.
This function allocates buffer for postprocessing (imgdata.image) and fills it with data layout compatible with LibRaw 0.13/0.14 and below. If the buffer is already allocated, it will be free()ed and allocated again.
This function should be called only if your code do postprocessing stage. If you use LibRaw's postprocessing calls (see below) you don't need to call raw2image().
The function returns an integer number in accordance with the return code convention: positive if any system call has returned an error, negative (from the LibRaw error list) if there has been an error situation within LibRaw.
This function releases the imgdata.image buffer allocated by raw2image();
This method should be called if current postprocessing results are not needed by the program (e.g. already copied somewhere), but new postprocessing calls (with another settings) are possible, so it is to early to call recycle().
The function calculates the correct size of the output image (imgdata.sizes.iwidth and imgdata.sizes.iheight) for the following cases:
In the aforementioned cases, the function changes the fields of the image output size; note that this change cannot be repeated again.
The function emulates the postprocessing capabilities available in dcraw.
Called after calling LibRaw::unpack();
The entire functionality of dcraw (set via the field values in imgdata.params) is supported, except for
The function is intended solely for demonstration and testing purposes; it is assumed that its source code will be used in most real applications as the reference material concerning the order of RAW data processing.
The function returns an integer number in accordance with the error code convention: positive if any system call has returned an error, negative (from the LibRaw error list) if there has been an error situation within LibRaw.
In spite of the abundance of libraries for file output in any formats, LibRaw includes calls that emulate the file output provided by dcraw. This is done primarily for easier verification of library work: the resultant files must be binary identical.
The function outputs the postprocessing results to a file in the PPM/PGM or TIFF format (the format is set via imgdata.params.output_tiff). The results are binary identical to those provided by dcraw.
The function returns an integer number in accordance with the error code convention: positive if any system call has returned an error, negative (from the LibRaw error list) if there has been an error situation within LibRaw.
Writes the thumbnail to a file in the PPM format for bitmap thumbnails and in the JPEG format for JPEG thumbnails, i.e., in the format completely identical to the results provided by dcraw.
The function returns an integer number in accordance with the error code convention: positive if any system call has returned an error, negative (from the LibRaw error list) if there has been an error situation within LibRaw.
There is several function calls for store unpacked data into memory buffer (after using dcraw_process() and so on):
This function returns size of postprocessed image:
Function parameters:
The function returns an integer number in accordance with the error code convention: positive if any system call has returned an error, negative (from the LibRaw error list) if there has been an error situation within LibRaw.
This function allocates memory buffer and stores unpacked-preprocessed image into this buffer. Function returns allocated structure libraw_processed_image_t with filled fields. Always returns data as RGB bitmap (i.e. type field is equal to LIBRAW_IMAGE_BITMAP).
dcraw_process() should be called before dcraw_make_mem_image();
Returns NULL in case of an error. If caller has passed not-NULL value as errorcode parameter, than *errorcode will be set to error code according to error code convention.
NOTE! Memory, allocated for return value will not be fried at destructor or LibRaw::recycle calls. Caller of dcraw_make_mem_image should free this memory by call to LibRaw::dcraw_clear_mem().
This function allocates memory buffer and stores thumbnail data in it. Function returns allocated structure libraw_processed_image_t with filled fields. For most RAW images allocated structure will contains JPEG image (i.e. type field is equal to LIBRAW_IMAGE_JPEG). For some cameras with RGB-bitmap thumbnail (Kodak SLRs) returned structure contains RGB bitmap (type field is equal to LIBRAW_IMAGE_JPEG, see structure description for details).
unpack_thumb() should be called before dcraw_make_mem_thumb();
Returns NULL in case of an error. If caller has passed not-NULL value as errorcode parameter, than *errorcode will be set to error code according to ñ error code convention.
NOTE! Memory, allocated for return value will not be fried at destructor or LibRaw::recycle calls. Caller of dcraw_make_mem_image should free this memory by call to LibRaw::dcraw_clear_mem().
This function will free the memory allocated by dcraw_make_mem_image or dcraw_make_mem_thumb.
This is static class member, so call syntax should be LibRaw::dcraw_clear_mem(...).
This call translates directly to free() system function, but it is better to use dcraw_clear_mem because LibRaw (DLL) may be compiled with memory manager other than in calling application.
LibRaw reads RAW-data by calling (virtual) methods of C++ object derived from LibRaw_abstract_datastream. This C++ class does not implement any read, but defines interface to be called. Call to base class methods always results in error.
This group of methods implements file object (FILE*) semantics.
Retuens -1 on error and 0 on success.
returns NULL on error or data pointer on success.
This group of methods includes several supplementary calls. These calls are used to temporary switch to another data stream (file and/or memory buffer).
This call implemented in base class (LibRaw_abstract_datastream), there is no need to
reimplement in in derived classes.
Possible activity of temporary datastream requires very accurate programming when implementing
datastreams derived from base LibRaw_abstract_datastream. See below
for more details.
There is three "standard" input classes in LibRaw distribution:
LibRaw C++ interface users can implement their own input classes and use them via LibRaw::open_datastream call. Requirements and implementation specifics are described below.
This class implements input from file.
Class methods:
All other class methods are described above.
This class implements all possble methods, including fname() and subfile_open().
This class implements input from file.
Class methods:
The difference between file and bigfile datastreams are obvious from class name: bigfile one supports large files (more than 2Gb) on all supported systems. File one uses streambuf interface which is limited to 2Gb on many systems.
All other class methods are described above.
This class implements all possble methods, including fname() and subfile_open().
This class implements input from memory buffer.
Class methods:
All other class methods are described above.
This class does not implement fname() and subfile_open() calls, so external JPEG metadata parsing
is not possible.
To create own read interface LibRaw user should implement C++ class derived from
LibRaw_abstract_datastream with all read methods.
LibRaw standard implementations may be used as reference. See libraw/libraw_datastream.h file for details
(all standard LibRaw input classes are implemented using inline functions only).
substream field, defined in base LibRaw_abstract_datastream class requires some additional notes.
This field is used when input switched to temporary buffer (used for Sony metadata processing). Unfortunately,
there is now ideal C++ way to hide this functionality into base class internals. So, any read call in
derived class should include 1-line statement like this:
int method(...args...){ if(substream) return substream->method(...args...). For example:
virtual int eof()
{
if(substream) return substream->eof();
....
virtual int scanf_one(const char *fmt, void* val)
{
if(substream) return substream->scanf_one(fmt,val);
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