adds help

Signed-off-by: Anton Dukhovnikov <[email protected]>

include/rawtoaces/acesrender.h

@@ -115,7 +115,7 @@ class AcesRender
     const libraw_processed_image_t *getImageBuffer() const;
     const struct Option             getSettings() const;
 
-protected:
+private:
     AcesRender();
     ~AcesRender();
     static AcesRender &getPrivateInstance();

src/rawtoaces_util2/rawtoaces_util.cpp

@@ -57,13 +57,64 @@ ImageConverter::ImageConverter()
     initArgParse();
 }
 
+const char *HelpString =
+    "Rawtoaces converts raw image files from a digital camera to "
+    "the Academy Colour Encoding System (ACES) compliant images.\n"
+    "The process consists of two parts:\n"
+    "- the colour values get converted from the camera native colour "
+    "space to the ACES AP0 (see \"SMPTE ST 2065-1\"), and \n"
+    "- the image file gets converted from the camera native raw "
+    "file format to the ACES Image Container file format "
+    "(see \"SMPTE ST 2065-4\").\n"
+    "\n"
+    "Rawtoaces supports the following white-balancing modes:\n"
+    "- \"metadata\" uses the white-balancing coefficients from the raw "
+    "image file, provided by the camera.\n"
+    "- \"illuminant\" performs white balancing to the illuminant, "
+    "provided in the \"--illuminant\" parameter. The list of the "
+    "supported illuminants can be seen using the "
+    "\"--list-illuminants\" parameter. This mode requires spectral "
+    "sensitivity data for the camera model the image comes from. "
+    "The list of cameras such data is available for, can be "
+    "seen using the \"--list-cameras\" parameter.\n"
+    "- \"box\" performs white-balancing to make the given region of "
+    "the image appear neutral gray. The box position (origin and size) "
+    "can be specified using the \"--wb-box\" parameter. In case no such "
+    "parameter provided, the whole image is used for white-balancing.\n"
+    "- \"custom\" uses the custom white balancing coefficients "
+    "provided using the -\"custom-wb\" parameter.\n"
+    "\n"
+    "Rawtoaces supports the following methods of color matrix "
+    "computation:\n"
+    "- \"spectral\" uses the camera sensor's spectral sensitivity data "
+    "to compute the optimal matrix. This mode requires spectral "
+    "sensitivity data for the camera model the image comes from. "
+    "The list of cameras such data is available for, can be "
+    "seen using the \"--list-cameras\" parameter.\n"
+    "- \"metadata\" uses the matrix (matrices) contained in the raw "
+    "image file metadata. This mode works best with the images using "
+    "the DNG format, as the DNG standard mandates the presense of "
+    "such matrices.\n"
+    "- \"Adobe\" uses the Adobe coefficients provided by LibRaw. \n"
+    "- \"custom\" uses a user-provided color conversion matrix. "
+    "A matrix can be specified using the \"--custom-mat\" parameter.\n"
+    "\n"
+    "The paths rawtoaces uses to search for the spectral sensitivity "
+    "data can be specified in the AMPAS_DATA_PATH environment "
+    "variable.\n";
+
+const char *UsageString =
+    "\n"
+    "    rawtoaces --wb-method METHOD --mat-method METHOD [PARAMS] "
+    "path/to/dir/or/file ...\n"
+    "Examples: \n"
+    "    rawtoaces --wb-method metadata --mat-method metadata raw_file.cr3\n"
+    "    rawtoaces --wb-method illuminant --illuminant 3200K --mat-method "
+    "spectral raw_file.cr3\n";
+
 void ImageConverter::initArgParse()
 {
-    _argParse
-        .intro(
-            "rawtoaces converts an raw image file from a digital camera to ACES." )
-        .usage( "usage\nusage" );
-
+    _argParse.intro( HelpString ).usage( UsageString );
     _argParse.print_defaults( true );
     _argParse.add_help( true );
     _argParse.add_version( "VERSION NUMBER" );