From ed86ded685d5892c745f30abc650a98565559ba7 Mon Sep 17 00:00:00 2001 From: giraffedata Date: Thu, 13 Sep 2012 21:51:52 +0000 Subject: miscellaneous update git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@1733 9d0c8265-081b-0410-96cb-a4ca84ce46f8 --- giftopnm.html | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) (limited to 'giftopnm.html') diff --git a/giftopnm.html b/giftopnm.html index a4a82b48..4e41f607 100644 --- a/giftopnm.html +++ b/giftopnm.html @@ -2,7 +2,7 @@ Giftopnm User Manual

giftopnm

-Updated: 25 May 2012 +Updated: 13 September 2012
Table Of Contents @@ -52,12 +52,13 @@ Netpbm output image has the wrong aspect ratio. In this case,
--alphaout=alpha-filename -
giftopnm creates a PBM file containing the alpha channel values in -the input image. If the input image doesn't contain an alpha channel, -the alpha-filename file contains all zero (transparent) alpha values. -If you don't specify --alphaout, giftopnm does not generate an -alpha file, and if the input image has an alpha channel, giftopnm -simply discards it. +
giftopnm creates a PBM file containing the transparency +information from the input image. This "alpha image" is the same +dimensions as the input image, and each pixel of the alpha image tells whether +the corresponding pixel of the input image is transparent. Black means +transparent; white means opaque. If you don't specify --alphaout, +giftopnm does not generate an alpha file, and if the input image has an +alpha channel, giftopnm simply discards it.

If you specify - as the filename, giftopnm writes the alpha output to Standard Output and discards the image. -- cgit 1.4.1