From f10af0d60f26d1e6b57c8c519773f5c40d36cdbd Mon Sep 17 00:00:00 2001 From: giraffedata Date: Sun, 13 Jan 2019 22:43:37 +0000 Subject: miscellaneous update git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@3500 9d0c8265-081b-0410-96cb-a4ca84ce46f8 --- directory.html | 2 +- pambrighten.html | 160 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ ppmbrighten.html | 14 +++-- ppmwheel.html | 42 ++++++--------- 4 files changed, 187 insertions(+), 31 deletions(-) create mode 100644 pambrighten.html diff --git a/directory.html b/directory.html index 26e3eeac..c81a7f39 100644 --- a/directory.html +++ b/directory.html @@ -765,7 +765,7 @@ a color map containing all possible colors of given maxval
pamfunc
apply simple arithmetic function to samples in an image -
ppmbrighten +
pambrighten
brighten or dim an image -- change saturation and value
ppmflash diff --git a/pambrighten.html b/pambrighten.html new file mode 100644 index 00000000..14102cd0 --- /dev/null +++ b/pambrighten.html @@ -0,0 +1,160 @@ + +Pambrighten User Manual + +

pambrighten

+Updated: 12 January 2019 +
+Table Of Contents + +

NAME

+pambrighten - change a PPM image's Saturation and Value + +

SYNOPSIS

+ +pambrighten +[-saturation=[+|-saturation_percent]] +[-value=[+|-value_percent]] +netpbmfile + +

Minimum unique abbreviation of option is acceptable. You may use +double hyphens instead of single hyphen to denote options. You may use +white space in place of the equals sign to separate an option name +from its value. + +

DESCRIPTION

+ +

This program is part of Netpbm. + +

pambrighten increases or decreases the Saturation and Value +(from the HSV color space) of each pixel of a Netpbm image. You specify +the percentage change for each of those parameters. + +

You can also remap the colors of the pixels so their Values cover the full +range of possible Values. + +

The output format is the same as the input format and any extra channels, +such as transparency, are passed through. + +

Hue-Saturation-Value, or HSV, is one way to represent a color, like the +more well-known RGB. Hue, Saturation, and Value are numbers in the range from +0 to 1. We always capitalize them in this document when we mean the number +from the HSV color space, especially since "value" as a conventional English +word has a much more abstract meaning. + +

Value is a measure of how bright the color is, relative to some specified +maximum (the Netpbm formats are also defined in terms of a specified maximum +brightness -- For the purposes of this program, they are the same). In +particular, it is the brightness of the brightest primary color component of +the color divided by the maximum brightness possible for a component. Zero +Value means black. White has full Value. + +

Hue is an indication of the secondary color with the same brightness that +most closely approximates the color. A secondary color is made of a +combination of at most two of the primary colors. + +

Saturation is a measure of how close the color is to the color indicated by +the Hue and Value. A lower number means more light of the third primary color +must be added to get the exact color. Full Saturation means the color is a +secondary color. Zero Saturation means the color is gray (or black or white). +Decreasing the saturation of a color tends to make it washed out. + +

If it is impossible to increase the Value of a pixel by the amount you +specify (e.g. the Value is .5 and you specify +200%), pambrighten +increases it to full Value instead. + +

If it is impossible to increase the Saturation of a pixel by the amount +you specify (e.g. it is already half saturated and you specify +200%), +pambrighten increases it to full Saturation instead. + +

For a simpler kind of brightening, you can use pamfunc -multiplier +simply to increase the brightness of each pixel by a specified percentage, +clipping each RGB component where the calculated brightness would exceed full +brightness. Thus, the brightest colors in the image would change chromaticity +in addition to not getting the specified brightness boost. For +decreasing brightness, pamfunc should do the same thing as +pambrighten. + +

ppmflash does another kind of brightening. It changes the color of +each pixel to bring it a specified percentage closer to white. This increases +the value and saturation. + +

pambrighten is the same as pambrighten, except that it +recognizes the various Netpbm image formats rather than treating them all as +PPM. The output format is the same as the input format and extra channels in +a PAM image (such as a transparency channel) get passed through. + +

If you want to modify the Hues in the image, use pamhue. + + +

EXAMPLES

+

To double the Value of each pixel: +

+pambrighten -value=100
+
+ +

To double the Saturation and halve the Value of each pixel: +

+pambrighten -saturation=+100 -value=-50
+
+ +

OPTIONS

+ +
+
-value=value_percent + +
This option specifies the amount, as a percentage, by which you want to +change the Value of each pixel. It may be negative. + +
-saturation=value_percent + +
This option specifies the amount, as a percentage, by which you want to +change the Saturation of each pixel. It may be negative. + +
+ +

SEE ALSO

+ +pnmnorm, +ppmdim, +pamfunc, +ppmflash, +pamaltsat, +ppmbrighten, +pamdepth, +pnmgamma, +pamhue, +ppmhist, +ppm + +

HISTORY

+ +

pambrighten was new in Netphm 10.86 (March 2019). It was a +PAM conversion of the much older ppmbrighten. + + +

AUTHOR

+ +

Copyright (C) 1990 by Brian Moffet. +Copyright (C) 1989 by Jef Poskanzer. + +

+Permission to use, copy, modify, and distribute this software and its +documentation for any purpose and without fee is hereby granted, provided +that the above copyright notice appear in all copies and that both that +copyright notice and this permission notice appear in supporting +documentation. This software is provided "as is" without express or +implied warranty. + +

+

Table Of Contents

+ + + diff --git a/ppmbrighten.html b/ppmbrighten.html index b2e450ac..7229bd64 100644 --- a/ppmbrighten.html +++ b/ppmbrighten.html @@ -2,7 +2,7 @@ Ppmbrighten User Manual

ppmbrighten

-Updated: 26 October 2012 +Updated: 12 January 2019
Table Of Contents @@ -78,6 +78,11 @@ For decreasing brightness, pamfunc should do the same thing as color of each pixel to bring it a specified per centage closer to white. This increases the value and saturation. +

pambrighten is the same as ppmbrighten, except that it +recognizes the various Netpbm image formats rather than treating them all as +PPM. The output format is the same as the input format and extra channels in +a PAM image (such as a transparency channel) get passed through. +

If you want to modify the Hues in the image, use pamhue. @@ -108,10 +113,8 @@ to change the Saturation of each pixel. It may be negative.

-normalize -
This option causes ppmbrighten to linearly remap the Values -of the pixels to cover the range 0 to 1. The option name is wrong -- -this operation is not normalization (it was named in error and the -name has been kept for backward compatibility). +
This option causes ppmbrighten to normalize contrast by linearly +remapping the Values of the pixels to cover the range 0 to 1.

ppmbrighten applies the brightening that you specify with the -value option after the remapping. @@ -128,6 +131,7 @@ with a bogus error message. ppmdim, pamfunc, ppmflash, +pambrighten, pamaltsat, pamdepth, pnmgamma, diff --git a/ppmwheel.html b/ppmwheel.html index ab23f503..ff62a609 100644 --- a/ppmwheel.html +++ b/ppmwheel.html @@ -2,21 +2,19 @@ Ppmwheel User Manual

ppmwheel

-Updated: 11 January 2003 +Updated: 13 January 2019
Table Of Contents - 

NAME

ppmwheel - make a PPM image of a color wheel -  -

SYNOPSIS

+

SYNOPSIS

+ ppmwheel diameter -  -

DESCRIPTION

+

DESCRIPTION

This program is part of Netpbm. @@ -25,48 +23,42 @@ specified diameter inside a white square just large enough to hold it.

The color wheel is based on the HSV color model. Hues are distributed angularly around the circle and the values are distributed -radially and the saturation is zero everywhere. The values are zero at +radially and the saturation is 100% everywhere. The values are zero at the center, increasing linearly to maximum at the edge. The maximum value corresponds to the maxval of the PPM image. -

Hence, the image contains all of the secondary colors based on the -red, green, and blue primary colors. A secondary color is one that is -composed of light of at most two of the three primary colors. +

Hence, the image consists of all of the secondary colors based on the red, +green, and blue primary colors. A secondary color is one that is composed of +light of at most two of the three primary colors. -  -

OPTIONS

+

OPTIONS

None. -  -

SEE ALSO

+

SEE ALSO

ppmcie, ppmrainbow, ppm -

HISTORY

- +

HISTORY

ppmwheel was added to Netpbm in Release 10.14 (March 2003). -  -

AUTHOR

+

AUTHOR

Copyright (C) 1995 by Peter Kirchgessner
-  -

Table Of Contents

+

Table Of Contents

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