Revision: 65170
http://sourceforge.net/p/brlcad/code/65170
Author: carlmoore
Date: 2015-06-03 20:03:40 +0000 (Wed, 03 Jun 2015)
Log Message:
-----------
redo parts of the bwmod man page
Modified Paths:
--------------
brlcad/trunk/doc/docbook/system/man1/en/bwmod.xml
Modified: brlcad/trunk/doc/docbook/system/man1/en/bwmod.xml
===================================================================
--- brlcad/trunk/doc/docbook/system/man1/en/bwmod.xml 2015-06-03 19:20:59 UTC
(rev 65169)
+++ brlcad/trunk/doc/docbook/system/man1/en/bwmod.xml 2015-06-03 20:03:40 UTC
(rev 65170)
@@ -35,10 +35,10 @@
The pixel values range from 0 to 255 and are internally operated on
in floating point form (unless the
<option>-c</option>
-option has been specified) so that dynamic range, truncation, and sign,
+option has been specified) so that dynamic range, truncation, and sign
are not a problem. On output they are converted back to 8-bit unsigned
-values clipping to 0 and 255 if necessary. The number of pixels clipped
-high and low, if any, are reported to standard error on completion.</para>
+values, with clipping to 0 and 255 for values less than 0 and greater than
255. If any pixels are clipped,
+the numbers of pixels clipped, low and high, are reported to standard error on
completion.</para>
<para>If the
<option>-c</option>
@@ -64,16 +64,16 @@
to divide by a value.
<!-- .br -->
<option>-A</option>
-to take to absolute value of each pixel.
+to take absolute value.
<!-- .br -->
<option>-e </option><replaceable>val</replaceable>
-to exponentiate, i.e. raise each pixel to the power
+to exponentiate, i.e. raise to the power
<emphasis remap='I'>val</emphasis>.
<!-- .br -->
<option>-r </option><replaceable>val</replaceable>
to take the
-<emphasis remap='I'>val</emphasis>
-root of each pixel.</para>
+<emphasis remap='I'>val</emphasis>th
+root.</para>
<para>All arguments can be floating point values. Note that this command
can be applied to color
@@ -86,16 +86,20 @@
<para>The command
<!-- .br -->
<userinput>bwmod -m-1 -a255 < file.bw > file2.bw</userinput>
-<!-- .br -->
+</para>
+<para>
will produce the negative of a file by first multiplying by minus
-one, and then adding 255 to shift the pixels back into the 0->255
range.</para>
+one, and then adding 255 to shift the pixels back into the 0->255 range.
+(I.e., replace each pixel value by 255 minus that value.)</para>
<para>One can apply a gamma factor to a file as follows:
<!-- .br -->
<userinput>bwmod -d255 -r2.2 -m255 < file.bw > file2.bw</userinput>
-<!-- .br -->
-which will first normalize the pixel values, then take the 2.2 root
-of each pixel, and finally scale it back to 0->255.
+</para>
+<para>
+which will first normalize the pixel values (i.e., put them into 0->1,
+noting the internal use of floating point), then take the 2.2 root
+of each value, and finally scale the pixel values back to 0->255.
[Note however that applying gammas this way is not recommended since
a function call per pixel results!]</para>
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