From 412ea2c1c8e8648262b79507a11ba8e141c4efee Mon Sep 17 00:00:00 2001 From: giraffedata Date: Sat, 29 Aug 2020 20:43:34 +0000 Subject: miscellaneous update git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@3936 9d0c8265-081b-0410-96cb-a4ca84ce46f8 --- winicontopam.html | 29 ++++++++++++++++++++--------- 1 file changed, 20 insertions(+), 9 deletions(-) diff --git a/winicontopam.html b/winicontopam.html index 53d3b357..3baa4d33 100644 --- a/winicontopam.html +++ b/winicontopam.html @@ -2,7 +2,7 @@ Winicontopam User Manual

winicontopam

-Updated: 12 April 2013 +Updated: 29 August 2020
Table Of Contents @@ -28,12 +28,21 @@ its value.

This program is part of Netpbm. -

winicontopam reads a Microsoft Windows icon file and -converts it to one or more RGB_ALPHA Netpbm PAM images. +

winicontopam reads a Microsoft Windows icon file and converts it to +one or more RGB_ALPHA Netpbm PAM images. -

The transparency channel is copied from the 8-bit transparency data from -the icon, if present. If no 8-bit transparency data is available, the -transparency channel is constructed from the so-called "AND mask". +

There are two kinds of transparency information a a Windows icon can have: +and mask and graded transparency map. The and mask is older and indicates for +each pixel whether it is fully opaque or fully transparent. The graded +transparency map can indicate translucent values too. The graded transparency +map is present in an icon that uses PNG encoding or uses BMP encoding with 32 +bits per pixel. + +

The transparency plane in the PAM output of winicontopam comes from + the graded transparency map if it exists and the and mask otherwise. + +

An icon may actually have both forms of transparency information. See +-andmasks.

The output goes to Standard Output. @@ -70,9 +79,11 @@ image (largest, then most bits per pixel).

-andmasks -

If the image to be extracted contains both 8-bit transparency -data and AND mask, produce five-channel Netpbm PAM images with the AND -mask as the fifth plane. +

If the image to be extracted contains both graded transparency data and an +AND mask, produce five-channel Netpbm PAM images with the AND mask as the +fifth plane. An image that formally has graded transparency data, but it +indicates nothing but opaque pixels is considered not to have graded +transparency data, so -andmasks would have no effect on it.

-verbose -- cgit 1.4.1