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|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>LibRaw C++ API</title>
</head>
<body>
<a href=index-eng.html>[back to Index]</a>
<h1>LibRaw C++ API</h1>
<p>Contents</p>
<ol>
<li><a href="#LibRaw">LibRaw Objects</a> </li>
<li><a href="#return">Returned values</a></li>
<li><a href="#dataload">Methods Loading Data from a File</a>
<ul>
<li><a href="#open_datastream">int LibRaw::open_datastream(LibRaw_abstract_datastream *stream)</a></li>
<li><a href="#open_file">int LibRaw::open_file(const char *rawfile[,INT64 bigfile_size])</a></li>
<li><a href="#open_buffer">int LibRaw::open_buffer(void *buffer, size_t bufsize)</a></li>
<li><a href="#unpack">int LibRaw::unpack(void)</a></li>
<li><a href="#unpack_thumb">int LibRaw::unpack_thumb(void)</a></li>
</ul>
</li>
<li><a href="#utility">Auxiliary Functions</a>
<ul>
<li>Library version info
<ul>
<li><a href="#version">const char* LibRaw::version()</a></li>
<li><a href="#versionNumber">int LibRaw::versionNumber()</a></li>
<li><a href="#LIBRAW_CHECK_VERSION">bool LIBRAW_CHECK_VERSION(major,minor,patch)</a>
</ul>
</li>
<li>List of supported cameras
<ul>
<li><a href="#cameraCount">int LibRaw::cameraCount()</a></li>
<li><a href="#cameraList">const char** LibRaw::cameraList()</a></li>
</ul>
</li>
<li><a href="#get_decoder_info">int LibRaw::get_decoder_info(libraw_decoder_info_t *)</a></li>
<li><a href="#unpack_function_name">const char* LibRaw::unpack_function_name()</a></li>
<li><a href="#recycle">void LibRaw::recycle(void)</a></li>
<li><a href="#~LibRaw">LibRaw::~LibRaw()</a></li>
<li><a href="#strprogress">const char* LibRaw::strprogress(enum LibRaw_progress code)</a></li>
<li><a href="#libraw_strerror">const char* LibRaw::strerror(int errorcode)</a></li>
<li><a href="#callbacks">Setting Error Notification Functions</a>
<ul>
<li><a href="#progress">User callback for progress indication/interruption</a></li>
<li><a href="#memerror">Out-of-Memory Notifier</a></li>
<li><a href="#dataerror">File Reading Notifier</a></li>
</ul>
</li>
</ul>
</li>
<li><a href="#dcrawemu">Data Postprocessing: Emulation of dcraw Behavior</a>
<ul>
<li><a href="#dcraw_params">Parameter Setting</a></li>
<li><a href="#raw2image">int LibRaw::raw2image</a></li>
<li><a href="#free_image">void LibRaw::free_image</a></li>
<li><a href="#adjust_sizes_info_only">int LibRaw::adjust_sizes_info_only(void)</a></li>
<li><a href="#dcraw_document_mode_processing">int LibRaw::dcraw_document_mode_processing(void)</a></li>
<li><a href="#dcraw_process">int LibRaw::dcraw_process(void)</a></li>
</ul>
</li>
<li><a href="#dcrawrite">Data Output to Files: Emulation of dcraw Behavior</a>
<ul>
<li><a href="#dcraw_ppm_tiff_writer">int LibRaw::dcraw_ppm_tiff_writer(const char *outfile)</a></li>
<li><a href="#dcraw_thumb_writer">int LibRaw::dcraw_thumb_writer(const char *thumbfile)</a></li>
</ul>
</li>
<li>
<a href="#memwrite">Copying unpacked data into memory buffer</a>
<ul>
<li>
<a href="#get_mem_image_format">void get_mem_image_format(int *widthp, int *heightp, int *colorsp, int
*bpp)</a>
</li>
<li>
<a href="#copy_mem_image">int LibRaw::copy_mem_image(void* scan0, int stride, int bgr)</a>
</li>
<li>
<a href="#dcraw_make_mem_image">libraw_processed_image_t *dcraw_make_mem_image(int *errorcode)</a>
</li>
<li>
<a href="#dcraw_make_mem_thumb">libraw_processed_image_t *dcraw_make_mem_thumb(int *errorcode)</a>
</li>
<li>
<a href"#dcraw_clear_mem">void LibRaw::dcraw_clear_mem(libraw_processed_image_t *)</a>
</li>
</ul>
</li>
<li><a href="#datastream">Input layer abstraction</a>
<ul>
<li><a href="LibRaw_abstract_datastream">class LibRaw_abstract_datastream - abstract RAW read interface<a>
<ul>
<li><a href="#datastream_methods">LibRaw_abstract_datastream class methods</a>
<ul>
<li><a href="#datastream_methods_utility">Object verification</a></li>
<li><a href="#datastream_methods_read">Stream read and positioning</a></li>
<li><a href="#datastream_methods_other">Other methods</a></li>
</ul>
</li>
</ul>
</li>
<li><a href="#datastream_derived">Derived input classes included in LibRaw</a>
<ul>
<li><a href="#file_datastream">class LibRaw_file_datastream - file input interface</a></li>
<li><a href="#bigfile_datastream">class LibRaw_file_datastream - file input interface for large files</a></li>
<li><a href="#buffer_datastream">class LibRaw_buffer_datastream - input from memory buffer</a></li>
</ul>
</li>
<li><a href="#own_datastreams">Own datastream derived classes</a>
<ul>
<li><a href="#substream">substream field: secondary input stream</a></li>
</ul>
<li>
</ul>
</li>
</ol>
<a name="LibRaw"></a>
<h2>LibRaw Objects</h2>
<p>
The main LibRaw object (class) is created either without parameters or with flags determining the object behavior.
</p>
<pre>
#include "libraw/libraw.h"
...
LibRaw ImageProcessor(unsigned int flags=0);
...
</pre>
<p>Flags (several flags are combined via operator |, i.e., bitwise OR):</P>
<ul>
<li><b>LIBRAW_OPTIONS_NO_MEMERR_CALLBACK</b>: do not set the standard
<a href="#callbacks">out-of-memory error handler</a> (standard handler outputs the error report in stderr);</li>
<li><b>LIBRAW_OPTIONS_NO_DATAERR_CALLBACK</b>: do not set the standard
<a href="#callbacks">file read error handler</a> (standard handler outputs the error report in stderr).</li>
</ul>
<p>
Three groups of methods are used for image processing
</p>
<ul>
<li><a href="#dataload">Data loading from the RAW file</a></li>
<li><a href="#dcrawemu">Postprocessing functions emulating the dcraw behavior</a></li>
<li><a href="#dcrawrite">File output functions emulating the dcraw behavior</a>.</li>
</ul>
<p>
The results of processing are placed in the imgdata field of type <a
href=API-datastruct-eng.html>libraw_data_t</a>; the same data set contains fields that control the postprocessing
and output.
</p>
<a name="return"></a>
<h2>Returned Values</h2>
<p>
All LibRaw API functions return an integer number in accordance with the
<a href=API-notes-eng.html#errors>return code convention</a>. Please read the descriptions of
<a href=API-notes-eng.html#errors>this convention</a> and <a href="#callbacks">LibRaw behavior
in cases of fatal errors</a>.
</p>
<a name="dataload"></a>
<h2>Methods Loading Data from a File</h2>
<a name=open_datastream></a>
<h3>int LibRaw::open_datastream(LibRaw_abstract_datastream *stream)</h3>
<p>Opens a datastream with RAW data, reads metadata (EXIF) from it, and fills the following structures:
</p>
<ul>
<li>imgdata.idata (<a href="API-datastruct-eng.html#libraw_iparams_t">libraw_iparams_t</a>),</li>
<li>imgdata.sizes (<a href="API-datastruct-eng.html#libraw_image_sizes_t">libraw_image_sizes_t</a>),</li>
<li>imgdata.color (<a href="API-datastruct-eng.html#libraw_colordata_t">libraw_colordata_t</a>),</li>
<li>imgdata.other (<a href="API-datastruct-eng.html#libraw_imgother_t">libraw_imgother_t</a>), and </li>
<li>imgdata.thumbnail (<a href="API-datastruct-eng.html#libraw_thumbnail_t">libraw_thumbnail_t</a>).</li>
</ul>
<p>The function returns an integer number in accordance with the <a href=API-notes-eng.html#errors>return
code convention</a>: positive if any system call has returned an error, negative
(from the <a href=API-datastruct-eng.html#LibRaw_errors>LibRaw error list</a>) if there has been an error
situation within LibRaw.
</p>
<p>Before file opening, <a href="#recycle">recycle()</a> 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.
</p>
<p><b>Input data</b>: pointer to object, derived from <a href="#datastream">LibRaw_abstract_datastream</a> class.
This object should be initialized and ready to read. This object should be destroyed in calling application
after use.
</p>
<a name=open_file></a>
<h3>int LibRaw::open_file(const char *filename[,INT64 bigfile_size])</h3>
<p>
Creates an <a href="#file_datastream">LibRaw_file_datastream</a> object, calls
<a href="#open_datastream">open_datastream()</a>. If succeed, sets internal flag which signals
to destroy internal datastream object on <a href="#recycle">recycle()</a>. On failure,
just created file_datastream destroyed immediately.
</p>
<p>
Second optional parameter <b>bigfile_size</b> controls background I/O interface used for file operations. For
files smaller than bigfile_size the <a href="#file_datastream">LibRaw_file_datastream</a> will be used and the <a href="#bigfile_datastream">LibRaw_bigfile_datastream</a> otherwise.
<p>The function returns an integer number in accordance with the
<a href=API-notes-eng.html#errors>return code convention</a>: positive if any system call has returned an error, negative
(from the <a href=API-datastruct-eng.html#LibRaw_errors>LibRaw error list</a>) if there has been an error
situation within LibRaw.
</p>
<a name=open_buffer></a>
<h3>int LibRaw::open_buffer(void *buffer, size_t bufsize)</h3>
<p>
Created an <a href="#buffer_datastream">LibRaw_buffer_datastream</a> object, calls
<a href="#open_datastream">open_datastream()</a>. If succeed, sets internal flag which signals
to destroy internal datastream object on <a href="#recycle">recycle()</a>. On failure,
just created file_datastream destroyed immediately.
</p>
<p>The function returns an integer number in accordance with the
<a href=API-notes-eng.html#errors>return code convention</a>: positive if any system call has returned an error, negative
(from the <a href=API-datastruct-eng.html#LibRaw_errors>LibRaw error list</a>) if there has been an error
situation within LibRaw.
</p>
<a name="unpack"></a>
<h3> int LibRaw::unpack(void)</h3>
<p>
Unpacks the RAW files of the image, calculates the black level (not for all formats). The results are placed in imgdata.image.
</p>
<p>
Data reading is sometimes (not frequently) affected by settings made in imgdata.params (<a
href="API-datastruct-eng.html#libraw_output_params_t">libraw_output_params_t</a>); see <a
href=API-notes-eng.html>API notes</a> for details.
</p>
<p>The function returns an integer number in accordance with the <a href=API-notes-eng.html#errors>return code
convention</a>: positive if any system call has returned an error, negative (from the
<a href=API-datastruct-eng.html#LibRaw_errors>LibRaw error list</a>) if there has been an error
situation within LibRaw.
</p>
<a name="unpack_thumb"></a>
<h3>int LibRaw::unpack_thumb(void)</h3>
<p>
Reads (or unpacks) the image preview (thumbnail), placing the result into the imgdata.thumbnail.thumb buffer.<br/>
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).<br/>
The thumbnail format is written to the imgdata.thumbnail.tformat field; for the possible values, see
<a href="API-datastruct-eng.html#LibRaw_thumbnail_formats">description of constants and data structures</a>.
</p>
<p>The function returns an integer number in accordance with the <a href=API-notes-eng.html#errors>return code
convention</a>: positive if any system call has returned an error, negative (from the
<a href=API-datastruct-eng.html#LibRaw_errors>LibRaw error list</a>) if there has been an error situation within
LibRaw.
</p>
<a name="utility"></a>
<h2>Auxiliary Functions</h2>
<h3>Library version check</h3>
<a name="version"></a>
<h4>const char* LibRaw::version()</h4>
<p>
Returns string representation of LibRaw version in MAJOR.MINOR.PATCH-Status format (i.e. 0.6.0-Alpha2
or 0.6.1-Release).
</p>
<a name="versionNumber"></a>
<h4>int LibRaw::versionNumber()</h4>
<p>
Returns integer representation of LibRaw version. During LibRaw development, the version number is always
increase .
</p>
<a name="LIBRAW_CHECK_VERSION"></a>
<h4>bool LIBRAW_CHECK_VERSION(major,minor,patch)</h4>
<p>
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).
</p>
<h3>List of supported RAW formats (cameras)</h3>
<a name="cameraCount"></a>
<h4>int LibRaw::cameraCount()</h4>
<p>
Returns count of cameras supported.
</p>
<a name="cameraList"></a>
<h4>const char** LibRaw::cameraList()</h4>
<p>
Returns list of supported cameras. Latest item of list is set to NULL (for easy printing).
</p>
<a name="get_decoder_info"></a>
<h4>int LibRaw::get_decoder_info(libraw_decoder_info_t *)</h4>
<p>
The function fills <a href=API-datastruct-eng.html#libraw_decoder_info_t>libraw_decoder_info_t</a>
structure by passed pointer with current raw decoder data.
</p>
<p>The function returns an integer number in accordance with the <a href=API-notes-eng.html#errors>return code
convention</a>: positive if any system call has returned an error, negative (from the
<a href=API-datastruct-eng.html#LibRaw_errors>LibRaw error list</a>) if there has been an error situation within
LibRaw.
</p>
<a name="unpack_function_name"></a>
<h3>const char* LibRaw::unpack_function_name()</h3>
<p>
Returns function name of file unpacking function. Intended only for LibRaw test suite designers to use in test
coverage evaluation.
</p>
<a name="subtract_black"></a>
<h4>void LibRaw::subtract_black()</h4>
<p>
This call will subtract black level values from RAW data (for suitable RAW data).
<a href="API-datastruct-eng.html#libraw_colordata_t">colordata.channel_maximum</a> and
<b>colordata.maximum</b> and black level data (<a
href="API-datastruct-eng.html#libraw_colordata_t">colordata.black</a> and colordata.cblack) will be adjusted
too.
</p>
<p>
This call should be used if you postprocess RAW data by your own code. LibRaw
<a href="#dcrawemu">postprocessing functions</a> will call <b>subtract_black()</b> by oneself.
</p>
<a name="recycle"></a>
<h3>void LibRaw::recycle(void)</h3>
<p>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.
</p>
<a name="~LibRaw"></a>
<h3>LibRaw::~LibRaw()</h3>
<p>Destructor, which consists in calling recycle().</p>
<a name="strprogress"></a>
<h3>const char* LibRaw::strprogress(enum LibRaw_progress code)</h3>
<p>Converts progress stage code to description string (in English).</p>
<a name="libraw_strerror"></a>
<h3>const char* LibRaw::strerror(int errorcode)</h3>
<p>Analog of strerror(3) function: outputs the text descriptions of LibRaw error codes (in English).</p>
<a name="callbacks"></a>
<h3>Setting Error Notification Functions</h3>
<p>
In process of RAW conversion LibRaw can call user-setted callback. This callback can be used for:
</p>
<ul>
<li>Dynamic status update (progress bar and so on).</li>
<li>Cancel of processing (for example, user pressed Cancel button).</li>
</ul>
<p>Also, work of the library may cause two types of exceptional situations that require notification of the calling application:
</p>
<ul>
<li>Memory shortage</li>
<li>Data read error.</li>
</ul>
<p>
An application may set its own callbacks that will be called in the cases mentioned above to notify the user (or the calling program).
</p>
<a name="progress"></a>
<h4>Progress indication/processing termination</h4>
<pre>
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);
</pre>
<p>
LibRaw user can set own callback which will be called 10-50 times during RAW postprocessing
by dcraw_process()/dcraw_document_mode_processing();
</p>
<p>
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()/dcraw_document_mode_processing() will return error code
LIBRAW_CANCELLED_BY_CALLBACK.
</p>
<p>
Callback parameters:
<dl>
<dt>void *callback_data</dt>
<dd>void*-pointer, passed as 2nd argument to set_progress_handler(). This pointer should be used to pass
additional data to callback (i.e. thread local data and so on).
</dd>
<dt>enum LibRaw_progress stage</dt>
<dd>Current processing stage. This number can be converted to string by call to
<a href="#strprogress">LibRaw::strprogress</a>. Not all processing stages are covered by callback calls.
</dd>
<dt>int iteration</dt>
<dd>Iteration number within current stage (from 0 to expected-1).
</dd>
<dt>int expected</dt>
<dd>Expected number of iterations on current stage.</dd>
</dl>
Callback should return value of: <b>0</b> for continue processing and <b>non-zero</b> for immediate cancel of processing.
</p>
<p>
If LibRaw compiled with OpenMP support, iteration parameter may not always increase within one stage. Out of
order callback calls are possible.
</p>
<p>
Callback code sample:
<pre>
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
}
</pre>
<a name="memerror"></a>
<h4>Out-of-Memory Notifier</h4>
<pre>
typedef void (* memory_callback)(void *callback_data,const char *file, const char *where);
void LibRaw::set_memerror_handler(memory_callback func,void *callback_data);
</pre>
<p>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:
</p>
<ul>
<li><b>void *callback_data</b> - void*-pointer, passed as 2nd argument to set_progress_handler(). This pointer
should be used to pass additional data to callback (i.e. thread local data and so on).</li>
<li><b>file</b> is the name of the RAW file whose processing evoked the out-of-memory error.
This name <b>can be NULL</b> if underlying data input layer does not know the name. So, if calling
application sets own callback, this callback should work with NULL file name.
</li>
<li><b>where</b> is the name of the function where memory shortage occurred.</li>
</ul>
<p>The callback function is intended for information purposes: it notifies the user
or the program code that processing is impossible.</p>
<p>If the user does not set his or her own handler, the standard one (output of error message in stderr) will be used.</p>
<p>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.
</p>
<p>In the case of memory shortage, processing of the current file is terminated and a notifier is called; all
allocated resources are freed, and <a href="#recycle">recycle()</a> is performed. The current call will return
LIBRAW_UNSUFFICIENT_MEMORY.
<br/>
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().
</p>
<a name="dataerror"></a>
<h4>File Read Error Notifier</h4>
<pre>
typedef void (*data_callback)(void *callback_data,const char *file, const int offset);
void LibRaw::set_dataerror_handler(data_callback func, void *callback_data);
</pre>
<p>
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:
</p>
<ul>
<li><b>void *callback_data</b> - void*-pointer, passed as 2nd argument to set_progress_handler(). This pointer
should be used to pass additional data to callback (i.e. thread local data and so on).</li>
<li><b>file</b> is the name of the RAW file whose processing evoked the file read error.
This name <b>can be NULL</b> if underlying data input layer does not know the name. So, if calling
application sets own callback, this callback should work with NULL file name.
</li>
<li><b>offset</b> is -1 at end-of-file (if LibRaw expects more data) or a positive number equal to
the file position (bytes from file beginning) where the unpacking error occurred.</li>
</ul>
<p>The callback function is intended for information purposes: it notifies the user
or the program code that processing is impossible.</p>
<p>If the user does not set his or her own handler, the standard one (output of error message in stderr) will be used.</p>
<p>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. </p>
<p>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 <a href="#recycle">recycle()</a> is performed. The current call will return
LIBRAW_IO_ERROR.
<br/>
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().
</p>
<a name="dcrawemu"></a>
<h2>Data Postprocessing: Emulation of dcraw Behavior</h2>
<p>
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()/
</p>
<a name="dcraw_params"></a>
<h3>Parameter Setting</h3>
<p>
Virtually all parameters that can be set through the dcraw command line are specified by assigning values to
fields of the <b>LibRaw::imgdata.params</b> structure. The type of this structure is
<b>libraw_output_params_t</b>; all fields are listed and described in sufficient detail in the <a
href="API-datastruct-eng.html#libraw_output_params_t">description of data structures</a>.
</p>
<a name="raw2image"></a>
<h3>int LibRaw::raw2image</h3>
<p>
This functions allocates buffer for postprocessing (imgdata.image) and fills it with data layout compatible
with LibRaw 0.13 and below. If the buffer is already allocated, it will be free()ed and allocated again.
</p>
<p>
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().
</p>
<p>The function returns an integer number in accordance with the <a href=API-notes-eng.html#errors>return code
convention</a>: positive if any system call has returned an error, negative (from the
<a href=API-datastruct-eng.html#LibRaw_errors>LibRaw error list</a>) if there has been an error situation within
LibRaw.
</p>
<a name="free_image"></a>
<h3>void LibRaw::free_image</h3>
<p>
This function releases the imgdata.image buffer allocated by raw2image();
</p>
<p>
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 <a href="#recycle">recycle()</a>.
</p>
<a name="adjust_sizes_info_only"></a>
<h3>int LibRaw::adjust_sizes_info_only(void)</h3>
<p>
The function calculates the correct size of the output image (imgdata.sizes.iwidth and imgdata.sizes.iheight) for the
following cases:
</p>
<ul>
<li>Files from Fuji cameras (with a 45-degree rotation)</li>
<li>Files from cameras with non-square pixels</li>
<li>Images shot by a rotated camera.</li>
</ul>
<p>
In the aforementioned cases, the function changes the fields of the image output size; note that
this change cannot be repeated again.
</p>
<p>
The function should be used for information purposes; it is incompatible with <a
href="#dcraw_document_mode_processing">dcraw_document_mode_processing()</a> and <a
href="#dcraw_process">dcraw_process()</a> calls.
</p>
<a name="dcraw_document_mode_processing"></a>
<h3>int LibRaw::dcraw_document_mode_processing(void)</h3>
<p>
The function emulates <b>dcraw -D</b>: no interpolation, white balance, and color conversion.<br/>
It is called after calling LibRaw::unpack();
</p>
<p>The function returns an integer number in accordance with the <a href=API-notes-eng.html#errors>error
code convention</a>: positive if any system call has returned an error, negative (from the
<a href=API-datastruct-eng.html#LibRaw_errors>LibRaw error list</a>) if there has been an error situation within
LibRaw.
</p>
<a name="dcraw_process"></a>
<h3>int LibRaw::dcraw_process(void)</h3>
<p>
The function emulates the postprocessing capabilities available in <b>dcraw</b>.<br/>
Called after calling LibRaw::unpack();
</p>
<p>The entire functionality of dcraw (set via the field values in <a
href="API-datastruct-eng.html#libraw_output_params_t">imgdata.params</a>) is supported, except for
</p>
<ul>
<li>Dark frame subtraction</li>
<li>Work with bad pixels.</li>
</ul>
<p>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.
</p>
<p>The function returns an integer number in accordance with the <a href=API-notes-eng.html#errors>error
code convention</a>: positive if any system call has returned an error, negative (from the
<a href=API-datastruct-eng.html#LibRaw_errors>LibRaw error list</a>) if there has been an error situation within
LibRaw.
</p>
<a name="dcrawrite"></a>
<h2>Data Output to Files: Emulation of dcraw Behavior</h2>
<p>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.
</p>
<a name="dcraw_ppm_tiff_writer"></a>
<h3>int LibRaw::dcraw_ppm_tiff_writer(const char *outfile)</h3>
<p>
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.
</p>
<p>The function returns an integer number in accordance with the <a href=API-notes-eng.html#errors>error
code convention</a>: positive if any system call has returned an error, negative (from the
<a href=API-datastruct-eng.html#LibRaw_errors>LibRaw error list</a>) if there has been an error situation within
LibRaw.
</p>
<a name="dcraw_thumb_writer"></a>
<h3>int LibRaw::dcraw_thumb_writer(const char *thumbfile)</h3>
<p>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.
</p>
<p>The function returns an integer number in accordance with the <a href=API-notes-eng.html#errors>error
code convention</a>: positive if any system call has returned an error, negative (from the
<a href=API-datastruct-eng.html#LibRaw_errors>LibRaw error list</a>) if there has been an error situation within
LibRaw.
</p>
<a name="memwrite"></a>
<h2>Copying unpacked data into memory buffer</h2>
<p>
There is several function calls for store unpacked data into memory buffer (after using dcraw_process() and so on):
<ul>
<li><b>get_mem_image_format</b> - get resulting bitmap size and bit depth.</li>
<li><b>copy_mem_image</b> - copy postprocessed data into some memory buffer with different color order and
line stride.
</li>
<li><b>dcraw_make_mem_image</b> - store processed image data into allocated buffer;
</li>
<li><b>dcraw_make_mem_thumb</b> - store extracted thumbnail into buffer as JPEG-file image (for most cameras)
or as RGB-bitmap.
</li>
</ul>
For usage primer see samples/mem_image.c sample.
</p>
<a name="get_mem_image_format"></a>
<h3>void get_mem_image_format(int *widthp, int *heightp, int *colorsp, int *bpp) const - return processing bitmap
size</h3>
<p>This function returns size of postprocessed image:
</p>
<ul>
<li>Image width is returned in *widthp;</li>
<li>Bitmap height is returned in *heightp;</li>
<li>Image color count is returned in *colorsp;</li>
<li>Bits per pixel (8 or 16) is returned in *bpp;</li>
</ul>
<a name="copy_mem_image"></a>
<h3>int LibRaw::copy_mem_image(void* scan0, int stride, int bgr) - copies postprocessed bitmap data into
buffer</h3>
<p>
Function parameters:
</p>
<ul>
<li>void *scan0 - pointer to buffer to copy data to. The buffer should be at least stride*image_height
bytes;</li>
<li>int stride - stride of each other image line (row) in bytes. Usually
image_width*(bit_per_pixel/8)*image_colors, but may be more if you wish to align image rows to, for example, 8
or 16 or 32 bytes to make CPU more happy.</li>
<li>int bgr - pixel copy order. RGB if bgr==0 and BGR overwise.</li>
</ul>
<p>The function returns an integer number in accordance with the <a href=API-notes-eng.html#errors>error
code convention</a>: positive if any system call has returned an error, negative (from the
<a href=API-datastruct-eng.html#LibRaw_errors>LibRaw error list</a>) if there has been an error situation within
LibRaw.
</p>
<a name="dcraw_make_mem_image"></a>
<h3>libraw_processed_image_t *dcraw_make_mem_image(int *errorcode=NULL) - store unpacked and processed image into
memory buffer as RGB-bitmap</h3>
<p>
This function allocates memory buffer and stores unpacked-preprocessed image into this buffer. Function returns
allocated structure <a href="API-datastruct-eng.html#libraw_processed_image_t">libraw_processed_image_t</a> with
filled fields. Always returns data as RGB bitmap (i.e. <b>type</b> field is equal to LIBRAW_IMAGE_BITMAP).
</p>
<p>
dcraw_process() or dcraw_document_mode_processing() should be called before dcraw_make_mem_image();
</p>
<p>
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 <a href="API-notes-eng.html#errors">error code convention</a>.
</p>
<p><b>NOTE!</b> Memory, allocated for return value will not be fried at destructor or <b>LibRaw::recycle</b>
calls. Caller of dcraw_make_mem_image should free this memory by call to <a
href="#dcraw_clear_mem">LibRaw::dcraw_clear_mem()</a>.
</p>
<a name="dcraw_make_mem_thumb"></a>
<h3>libraw_processed_image_t *dcraw_make_mem_thumb(int *errorcode=NULL) - store unpacked thumbnail into memory buffer</h3>
<p>
This function allocates memory buffer and stores thumbnail data in it. Function returns allocated
structure <a href="API-datastruct-eng.html#libraw_processed_image_t">libraw_processed_image_t</a> with
filled fields. For most RAW images allocated structure will contains JPEG image (i.e. <b>type</b>
field is equal to LIBRAW_IMAGE_JPEG). For some cameras with RGB-bitmap thumbnail (Kodak SLRs)
returned structure contains RGB bitmap (<b>type</b> field is equal to LIBRAW_IMAGE_JPEG, see structure
description for details).
</p>
<p>
unpack_thumb() should be called before dcraw_make_mem_thumb();
</p>
<p>
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 <a href=API-notes-eng.html#errors>error code convention</a>.
</p>
<p><b>NOTE!</b> Memory, allocated for return value will not be fried at destructor or <b>LibRaw::recycle</b>
calls. Caller of dcraw_make_mem_image should free this memory by call to <a
href="#dcraw_clear_mem">LibRaw::dcraw_clear_mem()</a>.
</p>
<h3>void LibRaw::dcraw_clear_mem(libraw_processed_image_t *)</h3>
<p>
This function will free the memory allocated by <b>dcraw_make_mem_image</b> or <b>dcraw_make_mem_thumb</b>.
</p>
<p>
This is static class member, so call syntax should be LibRaw::dcraw_clear_mem(...).
</p>
<p>
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.
</p>
<a name="datastream"></a>
<h2>Input layer abstraction</h2>
<a name="LibRaw_abstract_datastream"></a>
<h3>class LibRaw_abstract_datastream - abstract RAW read interface</h3>
<p>
LibRaw reads RAW-data by calling (virtual) methods of C++ object derived from
<b>LibRaw_abstract_datastream</b>. This C++ class does not implement any read, but defines interface to be
called. Call to base class methods always results in error.
</p>
<a name="datastream_methods"></a>
<h4>LibRaw_abstract_datastream class methods</h4>
<a name="datastream_methods_utility"></a>
<h5>Object verification</h5>
<dl>
<dt><b> virtual int valid()</b></dt>
<dd>Checks input datastream validity. Returns 1 on valid stream and 0 if datastream was created on non-valid
input parameters (wrong filename for file stream and so on).
</dd>
<a name="datastream_methods_read"></a>
<h5>Stream read and positioning</h5>
<p>This group of methods implements file object (FILE*) semantics.</p>
<dl>
<dt><b>virtual int read(void * ptr,size_t size, size_t nmemb)</b></dt>
<dd>
Similar to fread(ptr,size,nmemb,file).
</dd>
<dt><b>virtual int seek(off_t o, int whence)</b></dt>
<dd>
Similar to fseek(file,o,whence).
</dd>
<dt><b>virtual int tell(</b></dt>
<dd>
Similar to ftell(file).
</dd>
<dt><b>virtual int get_char()</b></dt>
<dd>
Similar to getc(file)/fgetc(file).
</dd>
<dt><b>virtual char* gets(char *s, int n)</b></dt>
<dd>
Similar to fgets(s,n,file).
</dd>
<dt><b>virtual int eof()</b></dt>
<dd>
Similar to feof(file).
</dd>
<dt><b>virtual int scanf_one(const char *fmt, void *val)</b></dt>
<dd>
Simplified variant of fscanf(file,fmt,val): format string is always contains one argument to read. So,
variable args call is not needed and only one pointer to data passed.
</dd>
</dl>
<a name="datastream_methods_other"></a>
<h5>Other methods</h5>
<p>This group of methods includes several supplementary calls. These calls are used to temporary switch to another
data stream (file and/or memory buffer).
</p>
<dl>
<dt><b>virtual const char* fname()</b></dt>
<dd>
Returns name of opened file if datastream object knows it (for example,
<b>LibRaw_file_datastream</b> used). Filename used in:
<ul>
<li>error notofocation callbacks;</li>
<li>generation of filename of JPEG-file with metadata when needed (i.e. cameras with 'Diag RAW hack').
</ul>
</dd>
<dt><b>virtual int subfile_open(const char *fn)</b></dt>
<dd>
This call temporary switches input to file <b>fn</b>. Returns 0 on success and error code on error.<br/>
The function used to read metadata from external JPEG file (on cameras with "Diag RAW hack").
<br/>
This call is not implemented for <a href="#buffer_datastream">LibRaw_buffer_datastream</a>, so
external JPEG processing is not possible when buffer datastream used.
<br/>
This functon should be implemented in real input class, base class call always return error.
<br/>
Working implementation sample can be found in
<a href="#file_datastream">LibRaw_file_datastream</a> implementation in <b>libraw/libraw_datastream.h</b> file.
</dd>
<dt><b> virtual void subfile_close()</b></dt>
<dd>
This call switches input stream from temporary open file back to main data stream.
</dd>
<dt><b> virtual int tempbuffer_open(void *buf, size_t size)</b></dt>
<dd>
This call temporary switches input to <a href="#buffer_datastream">LibRaw_buffer_datastream</a> object,
created from <b>buf</b>.<br/>
This method is needed for Sony encrypted metadata parser.
<p>
This call implemented in base class (<b>LibRaw_abstract_datastream</b>), there is no need to
reimplement in in derived classes.<br/>
Possible activity of temporary datastream requires very accurate programming when implementing
datastreams derived from base <b>LibRaw_abstract_datastream</b>. See <a href="#substream">below</a>
for more details.
</dd>
<dt><b> virtual void tempbuffer_close()</b></dt>
<dd>
This call switch input back from temporary datastream to main stream. This call implemented
in base <b>LibRaw_abstract_datastream</b> class.
</dd>
</dl>
<a name="datastream_derived"></a>
<h3>Derived input classes included in LibRaw</h3>
<p>
There is three "standard" input classes in LibRaw distribution:
</p>
<ul>
<li><a href="#file_datastream">LibRaw_file_datastream</a> implements input from file (in filesystem).</li>
<li><a href="#bigfile_datastream">LibRaw_bigfile_datastream</a> slower I/O, but files larger than 2Gb are supported.</li>
<li><a href="#buffer_datastream">LibRaw_buffer_datastream</a> implements input from memory buffer.</li>
</ul>
<p>
LibRaw C++ interface users can implement their own input classes and use them via
<a href="#open_datastream">LibRaw::open_datastream</a> call. Requirements and implementation specifics are
described below.
</p>
<a name="file_datastream"></a>
<h4>class LibRaw_file_datastream - file input interface</h4>
<p>
This class implements input from file.
</p>
<p><b>Class methods:</b></p>
<dl>
<dt><b> LibRaw_file_datastream(const char *fname) </b></dt>
<dd>
This constructor creates <b>LibRaw_file_datastream</b> object from file <b>fname</b>.<br/>
Unfortunately, C++ constructor cannot return an error. So if bad filename passed (e.g. nonexistent file)
object is created as non-valid (valid() call returns zero).
</dd>
</dl>
<p>
All other class methods are <a href="#datastream_methods">described above</a>.<br/>
This class implements all possble methods, including fname() and subfile_open().
</p>
<a name="bigfile_datastream"></a>
<h4>class LibRaw_bigfile_datastream - file input interface</h4>
<p>
This class implements input from file.
</p>
<p><b>Class methods:</b></p>
<dl>
<dt><b> LibRaw_bigfile_datastream(const char *fname) </b></dt>
<dd>
This constructor creates <b>LibRaw_bigfile_datastream</b> object from file <b>fname</b>.<br/>
Unfortunately, C++ constructor cannot return an error. So if bad filename passed (e.g. nonexistent file)
object is created as non-valid (valid() call returns zero).
</dd>
</dl>
<p>The difference between <b>file</b> and <b>bigfile</b> 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.
<p>
All other class methods are <a href="#datastream_methods">described above</a>.<br/>
This class implements all possble methods, including fname() and subfile_open().
</p>
<a name="buffer_datastream"></a>
<h4>class LibRaw_buffer_datastream - memory buffer input interface</h4>
<p>
This class implements input from memory buffer.
</p>
<p><b>Class methods:</b></p>
<dl>
<dt><b> LibRaw_buffer_datastream(void *buffer, size_t bsize)</b></dt>
<dd>
This constructor creates datastream object from <b>buffer</b> with size <b>bsize</b>.<br/>
It is not possibly to verify the pointer passed, so buffer address is checked against 0 and -1 only.
</dd>
</dl>
<p>
All other class methods are <a href="#datastream_methods">described above</a>.<br/>
This class does not implement fname() and subfile_open() calls, so external JPEG metadata parsing
is not possible.
</p>
<a name="own_datastreams"></a>
<h3>Own datastream derived classes</h3>
<p>
To create own read interface LibRaw user should implement C++ class derived from
<b>LibRaw_abstract_datastream</b> with all read methods.<br/>
LibRaw standard implementations may be used as reference. See <b>libraw/libraw_datastream.h</b> file for details
(all standard LibRaw input classes are implemented using inline functions only).
</p>
<a name="substream"></a>
<h4>substream field: secondary input stream</h4>
<p>
<b>substream</b> 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:<br/>
<b>int method(...args...){ if(substream) return substream->method(...args...)</b>. For example:
<pre>
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);
</pre>
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