From 92ba0e15d9ca554d0e012f50960f80f252a298c5 Mon Sep 17 00:00:00 2001 From: giraffedata Date: Tue, 5 Jan 2021 04:37:15 +0000 Subject: miscellaneous update git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@4023 9d0c8265-081b-0410-96cb-a4ca84ce46f8 --- pamtopng.html | 15 ++++++++++----- pnmtopng.html | 12 ++++++++++-- 2 files changed, 20 insertions(+), 7 deletions(-) diff --git a/pamtopng.html b/pamtopng.html index acdec95e..8cc0bfe8 100644 --- a/pamtopng.html +++ b/pamtopng.html @@ -142,9 +142,10 @@ library routine. E.g. red or rgb:ff/00/0d. This causes pamtopng to create a background color chunk in the PNG output which can be used for subsequent transparency channel or transparent color conversions. Specify color the same as for -transparent. +

-gamma=value -
This causes pnmtopng to create a gAMA chunk. This information +
This causes pamtopng to create a gAMA chunk. This information helps describe how the color values in the PNG must be interpreted. Without the gAMA chunk, whatever interprets the PNG must get this information separately (or just assume something standard). If your input is a true PPM @@ -154,7 +155,8 @@ gamma transfer function than the one specified for PPM. A common case of this is when the image is created by simple hardware that doesn't have digital computational ability. Also, some simple programs that generate images from scratch do it with a gamma transfer in which the gamma value is 1.0. - +

+

-chroma=chroma_list
This option specifies how red, green, and blue component values of a pixel specify a particular color, by telling the chromaticities @@ -226,12 +228,13 @@ string. There is no limit on the number of entries.
-ztxt=filename
The same as -text, except the text string is compressed in the -PNG output. pnmtopng uses zTXt chunks instead of a tEXt chunks. +PNG output. pamtopng uses zTXt chunks instead of a tEXt chunks. +

-itxt=filename
Similar to -text, but the text strings can be in a language other than English. The PNG image indicates what language that is and includes the -text string key both in English and that language. pnmtopng uses +text string key both in English and that language. pamtopng uses iTXt chunks instead of tEXt chunks.

For each record, you must specify the language and give the key both in @@ -254,7 +257,8 @@ The format is either a two character "nl" or an extended code like "en-US".

This option allows you to specify the modification time value to be placed in the PNG output. You can specify the year parameter either as a two or four digit value. - +

+

-interlace
This causes the PNG file to be interlaced, in Adam7 format. The interlaced @@ -285,6 +289,7 @@ when generating an interlaced PNG).
-verbose
This causes the program to display various facts about the conversion. +

diff --git a/pnmtopng.html b/pnmtopng.html index 8536c5e4..5067dd63 100644 --- a/pnmtopng.html +++ b/pnmtopng.html @@ -145,12 +145,14 @@ command line options:

This causes pnmtopng to display information about the format of the output file. +

-downscale
This enables pnmtopng to scale maxvalues of more then 65535 to 16 bits. Since this means loss of image data, pnmtopng does not do it by default. +

-interlace
@@ -168,6 +170,7 @@ top, so the displayer could display each row of the image as it arrives and gradually paint down to the bottom. But with an interlaced image, the displayer can start by showing a low-resolution version of the image, then gradually improve the display as more data arrives. +

-alpha=filename @@ -179,6 +182,7 @@ in the PNG format. If it can represent the transparency information through a palette, it will do so in order to make a smaller PNG file. pnmtopng even sorts the palette so it can omit the opaque colors from the transparency part of the palette and save space for the palette. +

-transparent=color
@@ -212,6 +216,7 @@ color does not appear in the image, there will be no transparency. Causes pnmtopng to create a background color chunk in the PNG output which can be used for subsequent transparency channel or transparent color conversions. Specify color the same as for -transparent. +

-palette=palettefile @@ -250,11 +255,13 @@ case of this is when the image is created by simple hardware that doesn't have digital computational ability. Also, some simple programs that generate images from scratch do it with a gamma transfer in which the gamma value is 1.0. +

-hist
Use this parameter to create a chunk that specifies the frequency (or histogram) of the colors in the image. +

-text=filename @@ -262,6 +269,7 @@ images from scratch do it with a gamma transfer in which the gamma value is This option lets you include arbitrary text strings in the PNG output, as tEXt chunks. +

filename is the name of a file that contains your text strings.

The output contains a distinct tEXt chunk for each entry in the file. @@ -302,7 +310,7 @@ key for the text string starts with "A" or "T". This odd exception exists for backward compatibility; we don't know why the program was originally designed this way, except that the distinction was meant to roughly identify the keys "Author" and "Title". - +

-rgb=chroma_list @@ -482,7 +490,7 @@ resulting PNG output is as similar to the Netpbm input as possible. For example, the PNG output will not be paletted and the transparency channel will be represented as a full transparency channel even if the information could be represented more succinctly with a transparency chunk. - +

-libversion -- cgit 1.4.1