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author | Jörg Frings-Fürst <debian@jff-webhosting.net> | 2015-11-06 05:38:49 +0100 |
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committer | Jörg Frings-Fürst <debian@jff-webhosting.net> | 2015-11-06 05:38:49 +0100 |
commit | 9491825ddff7a294d1f49061bae7044e426aeb2e (patch) | |
tree | 06e651099f87140ec534ae47fb8ce1ac6ec7976d /jpeg/rdjpgcom.1 | |
parent | fa756339d4204bff7f2820067f58214d32780d17 (diff) |
Imported Upstream version 1.8.3
Diffstat (limited to 'jpeg/rdjpgcom.1')
-rwxr-xr-x | jpeg/rdjpgcom.1 | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/jpeg/rdjpgcom.1 b/jpeg/rdjpgcom.1 new file mode 100755 index 0000000..97611df --- /dev/null +++ b/jpeg/rdjpgcom.1 @@ -0,0 +1,63 @@ +.TH RDJPGCOM 1 "02 April 2009" +.SH NAME +rdjpgcom \- display text comments from a JPEG file +.SH SYNOPSIS +.B rdjpgcom +[ +.B \-raw +] +[ +.B \-verbose +] +[ +.I filename +] +.LP +.SH DESCRIPTION +.LP +.B rdjpgcom +reads the named JPEG/JFIF file, or the standard input if no file is named, +and prints any text comments found in the file on the standard output. +.PP +The JPEG standard allows "comment" (COM) blocks to occur within a JPEG file. +Although the standard doesn't actually define what COM blocks are for, they +are widely used to hold user-supplied text strings. This lets you add +annotations, titles, index terms, etc to your JPEG files, and later retrieve +them as text. COM blocks do not interfere with the image stored in the JPEG +file. The maximum size of a COM block is 64K, but you can have as many of +them as you like in one JPEG file. +.SH OPTIONS +.TP +.B \-raw +Normally +.B rdjpgcom +escapes non-printable characters in comments, for security reasons. +This option avoids that. +.PP +.B \-verbose +Causes +.B rdjpgcom +to also display the JPEG image dimensions. +.PP +Switch names may be abbreviated, and are not case sensitive. +.SH HINTS +.B rdjpgcom +does not depend on the IJG JPEG library. Its source code is intended as an +illustration of the minimum amount of code required to parse a JPEG file +header correctly. +.PP +In +.B \-verbose +mode, +.B rdjpgcom +will also attempt to print the contents of any "APP12" markers as text. +Some digital cameras produce APP12 markers containing useful textual +information. If you like, you can modify the source code to print +other APPn marker types as well. +.SH SEE ALSO +.BR cjpeg (1), +.BR djpeg (1), +.BR jpegtran (1), +.BR wrjpgcom (1) +.SH AUTHOR +Independent JPEG Group |