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| author | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2007-01-29 02:02:48 +0000 |
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| committer | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2007-01-29 02:02:48 +0000 |
| commit | 08aa778e94e16817ed35b74a85d77526d0f378e3 (patch) | |
| tree | 227f1e4fe039815437580f49ff8b2cdb22e0c1c7 /giftopnm.html | |
| parent | 10009ad8936b152ef260ed5297af713a6a41a6ff (diff) | |
| download | netpbm-mirror-08aa778e94e16817ed35b74a85d77526d0f378e3.tar.gz netpbm-mirror-08aa778e94e16817ed35b74a85d77526d0f378e3.tar.xz netpbm-mirror-08aa778e94e16817ed35b74a85d77526d0f378e3.zip | |
"miscellaneous update"
git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@216 9d0c8265-081b-0410-96cb-a4ca84ce46f8
Diffstat (limited to 'giftopnm.html')
| -rw-r--r-- | giftopnm.html | 40 |
1 files changed, 38 insertions, 2 deletions
diff --git a/giftopnm.html b/giftopnm.html index 3a3d2f2e..60a2ebe9 100644 --- a/giftopnm.html +++ b/giftopnm.html @@ -2,7 +2,7 @@ <HTML><HEAD><TITLE>Giftopnm User Manual</TITLE></HEAD> <BODY> <H1>giftopnm</H1> -Updated: 6 August 2006 +Updated: 29 January 2007 <BR> <A HREF="#index">Table Of Contents</A> @@ -16,6 +16,7 @@ giftopnm - convert a GIF file into a PNM image [<B>-verbose</B>] [<B>-comments</B>] [<B>-image=</B>{<I>N</I>,<B>all</b>}] +[<B>-repair</B>] [<B>-quitearly</B>] [<I>GIFfile</I>] @@ -98,9 +99,44 @@ not do the same for the images after it; see <b>-quitearly</b>. <p>The <b>all</b> value was added in Netpbm 10.16 (June 2003). Earlier <b>giftopnm</b> can extract only one image. +<dt><b>-repair</b> + +<dd>This option makes <b>giftopnm</b> try to salvage what it can from an +invalid GIF input. + +<p>In particular, when <b>giftopnm</b> detects that the GIF input is +invalid so that it is impossible to determine what the pixels are +intended to be, it produces a single arbitrary color for all further +pixels in the image. <b>giftopnm</b> processes the image from top to +bottom, left to right, so this means the bottommost pixels will be +this padding. + +<p><b>giftopnm</b> issues warning messages when it salvages an image +in this way. + +<p>Without this option, <b>giftopnm</b> fails when it detects invalid +GIF input. Any output it produces is arbitrary, and typically is not +a valid PNM image. + +<p>It is fairly common for an image to be corrupted such that is +started off as a valid GIF, but had the end of the file cut off. An +interrupted network transfer tends to do this. In this case, +<b>giftopnm</b>'s salvage operation will produce a valid PNM image of +the proer dimensions, but with a single arbitrary color for the pixels +that were left out of the file. If the truncation is in the middle of +a row, <b>giftopnm</b> produces arbitrary pixels for the entire +truncated row. + +<p>This option was new in Netpbm 10.38 (March 2007). From 10.32 through +10.37, <b>giftopnm</b> always fails if it detects invalid GIF input. +Before 10.32, it succeeds in the case of a truncated image, and replaces +the missing pixels with arbitrary colors, not necessarily all the same +(The pre-10.32 behavior wasn't actually intended by the design). + + <dt><b>-quitearly</b> -<dd>This options makes <b>giftopnm</b> stop reading its input file as soon +<dd>This option makes <b>giftopnm</b> stop reading its input file as soon as it has converted and output the images from the input that you requested. By default, <b>giftopnm</b> reads until the end of the GIF stream, ignoring any data after the images you requested. |