commit b83f9d9d17b605a1305c8445f1b0cbb2906d225f
parent aa49a2927171afb33a9949173de3a61bd9371a89
Author: Vincent Forest <vincent.forest@meso-star.com>
Date: Fri, 3 Apr 2020 16:57:04 +0200
Fix the man page
Take into account the Najda's review
Diffstat:
1 file changed, 18 insertions(+), 18 deletions(-)
diff --git a/doc/htpp.1.txt b/doc/htpp.1.txt
@@ -29,16 +29,18 @@ htpp [_option_] ... [_input_]
DESCRIPTION
-----------
-*htpp* post-processes a *htrdr-image*(5) and convert it to a regular PPM image
-[1]. If _input_ is not defined, the *htrdr-image*(5) is read from standard
-input. Two post-processing procedures are provided: the post-processing of the
-image colors (option *-i*), and the mapping of a given pixel component onto a
-color ramp (option "*-m*). By default, *htpp* post-process the image color.
+
+*htpp* post-processes a *htrdr-image*(5) and converts it to a regular PPM
+image [1]. If _input_ is not defined, the *htrdr-image*(5) is read from
+standard input. Two post-processing procedures are provided: the
+post-processing of the image colors (option *-i*), and the mapping of a given
+pixel component onto a color ramp (option "*-m*). By default, *htpp*
+post-processes the image color.
To post-process the image colors (option *-i*) *htpp* assumes that the first,
-the third and the fifth component of each *htrdr-image*(5) pixel encodes a
-color with respect to the CIE 1931 XYZ color space. *htpp* first
-tone maps these colors with the following filmic tone mapping operator [2]:
+the third and the fifth components of each *htrdr-image*(5) pixel encode a
+color with respect to the CIE 1931 XYZ color space. *htpp* first tone maps
+these colors with the following filmic tone mapping operator [2]:
out-color = f(in-color * exposure) / f(white-scale)
@@ -53,20 +55,18 @@ with:
E = 0.02
F = 0.30
-The _exposure_ term is an user defined parameter provided as the _exposure_
+The _exposure_ term is an user-defined parameter provided as the _exposure_
image option. If not defined, a default _exposure_ of 1 is used. The
_white-scale_ factor is either defined by the user through the _white_ image
-option or automatically computed as the luminance from which roughly all image
-pixels have a luminance less than _white-scale_. Currently, *htpp* empirically
-defines _white-scale_ as the luminance greater than the luminance of 99.5% of
-the pixels. Once tone mapped, the pixels are transformed from the CIE 1931 XYZ
-color space to the sRGB linear color space before to be gamma corrected.
-Finally, the resulting pixel components are clamped to [0, 1] and encoded on
-8-bits.
+option or automatically computed as the luminance that is such that 99.5% of
+pixel radiances are less than _white-scale_. Once tone mapped, the pixels are
+transformed from the CIE 1931 XYZ color space into the sRGB linear color space
+before being gamma corrected. Finally, the resulting pixel components are
+clamped to [0, 1] and encoded on 8-bits.
The mapping of a pixel component onto a color ramp is controlled by the *-m*
option. The pixel component to post-process is defined by the _pixcpnt_
-mapping option. *htpp* normalized this component according to its range onto
+mapping option. *htpp* normalizes this component according to its range onto
the whole image or with respect to the _range_ mapping option if it is
defined. The resuling value is then mapped to a built-in color ramp whose name
is defined by the _palette_ mapping option.
@@ -81,7 +81,7 @@ OPTIONS
*-i* <__sub-option__>[:<__sub-option__> ...]::
Post-process the color of the *htrdr-image*(5). The first, the third and the
- fifth pixel component are assumed to store the pixel color encoded into the
+ fifth pixel components are assumed to store the pixel color encoded into the
CIE 1931 XYZ color space. Available sub-options are:
**default**;;
