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| author | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2012-09-13 21:51:52 +0000 |
|---|---|---|
| committer | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2012-09-13 21:51:52 +0000 |
| commit | ed86ded685d5892c745f30abc650a98565559ba7 (patch) | |
| tree | 16f1aa25d437a7623d47caef6fcad376a4c98936 /giftopnm.html | |
| parent | 205cb067c5f6b3fbad4b87233a98444d8b400ff0 (diff) | |
| download | netpbm-mirror-ed86ded685d5892c745f30abc650a98565559ba7.tar.gz netpbm-mirror-ed86ded685d5892c745f30abc650a98565559ba7.tar.xz netpbm-mirror-ed86ded685d5892c745f30abc650a98565559ba7.zip | |
miscellaneous update
git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@1733 9d0c8265-081b-0410-96cb-a4ca84ce46f8
Diffstat (limited to 'giftopnm.html')
| -rw-r--r-- | giftopnm.html | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/giftopnm.html b/giftopnm.html index a4a82b48..4e41f607 100644 --- a/giftopnm.html +++ b/giftopnm.html @@ -2,7 +2,7 @@ <HTML><HEAD><TITLE>Giftopnm User Manual</TITLE></HEAD> <BODY> <H1>giftopnm</H1> -Updated: 25 May 2012 +Updated: 13 September 2012 <BR> <A HREF="#index">Table Of Contents</A> @@ -52,12 +52,13 @@ Netpbm output image has the wrong aspect ratio. In this case, <DL COMPACT> <DT><B>--alphaout=</B><I>alpha-filename</I> -<DD><B>giftopnm </B> creates a PBM file containing the alpha channel values in -the input image. If the input image doesn't contain an alpha channel, -the <I>alpha-filename</I> file contains all zero (transparent) alpha values. -If you don't specify <B>--alphaout</B>, <B>giftopnm</B> does not generate an -alpha file, and if the input image has an alpha channel, <B>giftopnm</B> -simply discards it. +<DD><B>giftopnm </B> 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 <B>--alphaout</B>, +<B>giftopnm</B> does not generate an alpha file, and if the input image has an +alpha channel, <B>giftopnm</B> simply discards it. <P>If you specify <B>-</B> as the filename, <B>giftopnm</B> writes the alpha output to Standard Output and discards the image. |