--- ray/doc/man/man1/pvalue.1	2003/09/13 15:24:13	1.2
+++ ray/doc/man/man1/pvalue.1	2024/09/11 18:56:11	1.13
@@ -1,4 +1,4 @@
-.\" RCSid "$Id"
+.\" RCSid "$Id: pvalue.1,v 1.13 2024/09/11 18:56:11 greg Exp $"
 .TH PVALUE 1 1/15/99 RADIANCE
 .SH NAME
 pvalue - convert RADIANCE picture to/from alternate formats
@@ -42,15 +42,23 @@ these files.
 .TP 10n
 .BR \-u
 Print only unique values in the output, skipping runs of equal pixels.
+For reverse conversions, the
+.I \-u
+option writes uncompressed output rather than the standard run-length RGBE
+encoding.
 Specifying
 .I \+u
 turns this option off, which is the default.
 .TP
 .BR \-o
 Print original values, before exposure compensation.
+If the input file is in XYZE format, the Y (green) channel
+will correspond to units of candelas/meter^2, unless
+.I \-O
+is specified, when watts/sr/meter^2 are always reported.
 Specifying
 .I \+o
-uses final values, which is the default.
+uses final exposed values, which is the default.
 .TP
 .BR \-h
 Do not print header.
@@ -73,7 +81,6 @@ causes the resolution string to be printed, which is t
 Skip the specified number of bytes on the input header.
 This option is useful for skipping unintelligible headers in
 foreign file formats.
-(Does not work when reading from standard input.)
 .TP
 .BI \-e \ exposure
 Adjust the exposure by the amount specified.
@@ -177,6 +184,14 @@ Specifying
 converts from a Radiance picture to other values, which is the
 default.
 .TP
+.BI \-p " xr yr xg yg xb yb xw yw"
+On reverse conversion, RGB input uses the given set of color primaries.
+These are written into the output header with the PRIMARIES variable.
+.TP
+.BR \-pXYZ
+On reverse conversion, input is in CIE XYZ coordinates, rather than RGB.
+The Y channel is assumed to be in candelas/meter^2.
+.TP
 .BI -y \ res
 Set the output y resolution to
 .I res.
@@ -207,7 +222,7 @@ options determines whether the scanlines are sorted al
 x or along y.
 Most Radiance pictures are sorted top to bottom, then left
 to right.
-This corresponds to a specification of the form "-y yres +x xres".
+This corresponds to a specification of the form "\-y yres +x xres".
 Either an upper or lower case 'X' may be used for this option.
 Like the
 .I \-y
@@ -217,25 +232,27 @@ options have no effect for forward conversions.
 .SH EXAMPLE
 To look at the original, unique pixels in picture:
 .IP "" .2i
-pvalue -o -u picture | more
+pvalue \-o \-u picture | more
 .PP
 To convert from a 512x400 8-bit greyscale image in bottom to top,
 left to right scanline ordering:
 .IP "" .2i
-pvalue -r -db -b -h +y 400 +x 512 input.im > flipped.pic
+pvalue \-r \-db \-b \-h +y 400 +x 512 input.im > flipped.hdr
 .br
-pflip -v flipped.pic > final.pic
+pflip \-v flipped.hdr > final.hdr
+.SH NOTES
+Hyperspectral Radiance pictures (.hsr files) are
+converted to approximate RGB.
+However, the colors may not be very accurate.
+Use
+.I rcomb(1)
+for conversion if greater color fidelity is required.
 .SH AUTHOR
 Greg Ward
 .SH BUGS
-The
-.I \-r
-option does not work with the
-.I \-u
-option.
-Also, input pixel locations are ignored during a reverse
+Input pixel locations are ignored during a reverse
 conversion, so this information is not used in determining
 the scanline ordering or picture size.
 .SH "SEE ALSO"
 getinfo(1), pcompos(1), pfilt(1), pflip(1),
-protate(1), rpict(1), rtrace(1), rview(1)
+protate(1), ra_xyze(1), rcomb(1), rpict(1), rtrace(1), rvu(1)