--- ray/doc/man/man1/pcomb.1	2003/10/21 15:08:19	1.3
+++ ray/doc/man/man1/pcomb.1	2018/05/04 23:56:49	1.11
@@ -1,10 +1,12 @@
-.\" RCSid "$Id"
+.\" RCSid "$Id: pcomb.1,v 1.11 2018/05/04 23:56:49 greg Exp $"
 .TH PCOMB 1 8/31/96 RADIANCE
 .SH NAME
 pcomb - combine RADIANCE pictures
 .SH SYNOPSIS
 .B pcomb
 [
+.B -h
+][
 .B -w
 ][
 .B "\-x xres"
@@ -40,6 +42,9 @@ but an arbitrary mapping can be assigned with the
 and
 .I \-f
 options.
+The variable and function definitions in each
+.I \-f source
+file are read and compiled from the RADIANCE library where it is found.
 Negative coefficients and functions are allowed, and
 .I pcomb
 will produce color values of zero where they would be negative.
@@ -68,7 +73,7 @@ For example,
 would return the red component of the pixel from picture 3
 that is left 2 and up 1 from the current position.
 Although x offsets may be as large as width of the picture,
-y offsets are limited to a small window (+/- 8 pixels) due to efficiency
+y offsets are limited to a small window (+/- 32 pixels) due to efficiency
 considerations.
 However, it is not usually necessary to worry about this problem --
 if the requested offset is not available, the next best pixel is
@@ -138,8 +143,17 @@ If the current pixel is outside the view region,
 will return a negative value, and
 .I S(n)
 will return zero.
+The first input picture with a view is assumed to correspond to the
+view of the output picture, which is written into the header.
 .PP
 The
+.I \-h
+option may be used to reduce the information header size, which
+can grow disproportionately after multiple runs of
+.I pcomb
+and/or
+.I pcompos(1).
+The
 .I \-w
 option can be used to suppress warning messages about invalid
 calculations.
@@ -189,24 +203,26 @@ by preceeding it with an exclamation point ('!').
 .SH EXAMPLES
 To produce a picture showing the difference between pic1 and pic2:
 .IP "" .2i
-pcomb -e 'ro=ri(1)-ri(2);go=gi(1)-gi(2);bo=bi(1)-bi(2)' pic1 pic2 > diff
+pcomb \-e 'ro=ri(1)\-ri(2);go=gi(1)\-gi(2);bo=bi(1)\-bi(2)' pic1 pic2 > diff
 .PP
 Or, more efficiently:
 .IP "" .2i
-pcomb pic1 -s -1 pic2 > diff
+pcomb pic1 \-s \-1 pic2 > diff
 .PP
 To precompute the gamma correction for a picture:
 .IP "" .2i
-pcomb -e 'ro=ri(1)^.4;go=gi(1)^.4;bo=bi(1)^.4' pic > pic.gam
+pcomb \-e 'ro=ri(1)^.4;go=gi(1)^.4;bo=bi(1)^.4' inp.hdr > gam.hdr
 .PP
 To perform some special filtering:
 .IP "" .2i
-pcomb -f myfilt.cal -x xmax/2 -y ymax/2 input.pic > filtered.pic
+pcomb \-f myfilt.cal \-x xmax/2 \-y ymax/2 input.hdr > filtered.hdr
 .PP
 To make a picture of a dot:
 .IP "" .2i
-pcomb -x 100 -y 100 -e 'ro=b;go=b;bo=b;b=if((x-50)^2+(y-50)^2-25^2,0,1)' > dot
+pcomb \-x 100 \-y 100 \-e 'ro=b;go=b;bo=b;b=if((x-50)^2+(y-50)^2\-25^2,0,1)' > dot
+.SH ENVIRONMENT
+RAYPATH		the directories to check for auxiliary files.
 .SH AUTHOR
 Greg Ward
 .SH "SEE ALSO"
-calc(1), getinfo(1), pcompos(1), pfilt(1), rpict(1)
+getinfo(1), icalc(1), pcompos(1), pfilt(1), rpict(1)