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| author | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2019-03-13 21:36:20 +0000 |
|---|---|---|
| committer | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2019-03-13 21:36:20 +0000 |
| commit | ebfec1b842c189ee719b94208ff162b1d188b728 (patch) | |
| tree | 8d38d822ae9bf3ea86382e009aa62150f1b456cc /pnmtopng.html | |
| parent | 9c318b08553e2dd326627b8583b3b4a46f44d5e0 (diff) | |
| download | netpbm-mirror-ebfec1b842c189ee719b94208ff162b1d188b728.tar.gz netpbm-mirror-ebfec1b842c189ee719b94208ff162b1d188b728.tar.xz netpbm-mirror-ebfec1b842c189ee719b94208ff162b1d188b728.zip | |
miscellaneous update
git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@3568 9d0c8265-081b-0410-96cb-a4ca84ce46f8
Diffstat (limited to 'pnmtopng.html')
| -rw-r--r-- | pnmtopng.html | 31 |
1 files changed, 24 insertions, 7 deletions
diff --git a/pnmtopng.html b/pnmtopng.html index d808766b..167291aa 100644 --- a/pnmtopng.html +++ b/pnmtopng.html @@ -3,7 +3,7 @@ <HEAD><TITLE>Pnmtopng User Manual</TITLE></HEAD> <BODY> <H1>pnmtopng</H1> -Updated: 09 October 2016 +Updated: 13 March 2019 <BR> <A HREF="#index">Table Of Contents</A> @@ -135,18 +135,35 @@ with "unrecognized option," fall back to the old syntax. <DL COMPACT> <DT><B>-verbose</B> <DD> - Display the format of the output file. +This causes <b>pnmtopng</b> to display information about the format of the +output file. + <DT><B>-downscale</B> <DD> - Enables scaling of maxvalues of more then 65535 to 16 bit. Since - this means loss of image data, <b>pnmtopng</b> does not do it by - default. +This enables <b>pnmtopng</b> to scale maxvalues of more then 65535 to 16 +bits. Since this means loss of image data, <b>pnmtopng</b> does not do it by +default. + <DT><B>-interlace</B> <DD> - Creates an interlaced PNG file (Adam7). +This causes the PNG file to be interlaced, in Adam7 format. The interlaced +format is one in which the raster data starts with a low-resolution +representation of the entire image, then continues with additional information +for the entire image, then even more information, etc. In Adam7 in +particular, there are seven such passes of the whole image. This is useful +when you are receiving the image over a slow communication line as someone is +waiting to see it. The simplest thing to do in that case is wait for the +entire image to arrive and then display it instantly, but then the user is +wasting time staring at a blank space until the whole image arrives. With the +standard non-interlaced format, the data arrives row-by-row starting at the +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. + <DT><B>-alpha=</b><i>filename</i> -<DD> This specifies the transparency (alpha) channel of the image. You supply +<DD>This specifies the transparency (alpha) channel of the image. You supply the transparency channel as a standard PGM transparency mask (see the <a href="pgm.html">PGM</a> specification. <b>pnmtopng</b> does not necessarily represents the transparency information as a transparency channel |