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diff --git a/jpeg/wrjpgcom.1 b/jpeg/wrjpgcom.1 new file mode 100644 index 0000000..d419a99 --- /dev/null +++ b/jpeg/wrjpgcom.1 @@ -0,0 +1,103 @@ +.TH WRJPGCOM 1 "15 June 1995" +.SH NAME +wrjpgcom \- insert text comments into a JPEG file +.SH SYNOPSIS +.B wrjpgcom +[ +.B \-replace +] +[ +.BI \-comment " text" +] +[ +.BI \-cfile " name" +] +[ +.I filename +] +.LP +.SH DESCRIPTION +.LP +.B wrjpgcom +reads the named JPEG/JFIF file, or the standard input if no file is named, +and generates a new JPEG/JFIF file on standard output. A comment block is +added to the file. +.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. +.PP +.B wrjpgcom +adds a COM block, containing text you provide, to a JPEG file. +Ordinarily, the COM block is added after any existing COM blocks; but you +can delete the old COM blocks if you wish. +.SH OPTIONS +Switch names may be abbreviated, and are not case sensitive. +.TP +.B \-replace +Delete any existing COM blocks from the file. +.TP +.BI \-comment " text" +Supply text for new COM block on command line. +.TP +.BI \-cfile " name" +Read text for new COM block from named file. +.PP +If you have only one line of comment text to add, you can provide it on the +command line with +.BR \-comment . +The comment text must be surrounded with quotes so that it is treated as a +single argument. Longer comments can be read from a text file. +.PP +If you give neither +.B \-comment +nor +.BR \-cfile , +then +.B wrjpgcom +will read the comment text from standard input. (In this case an input image +file name MUST be supplied, so that the source JPEG file comes from somewhere +else.) You can enter multiple lines, up to 64KB worth. Type an end-of-file +indicator (usually control-D) to terminate the comment text entry. +.PP +.B wrjpgcom +will not add a COM block if the provided comment string is empty. Therefore +\fB\-replace \-comment ""\fR can be used to delete all COM blocks from a file. +.SH EXAMPLES +.LP +Add a short comment to in.jpg, producing out.jpg: +.IP +.B wrjpgcom \-c +\fI"View of my back yard" in.jpg +.B > +.I out.jpg +.PP +Attach a long comment previously stored in comment.txt: +.IP +.B wrjpgcom +.I in.jpg +.B < +.I comment.txt +.B > +.I out.jpg +.PP +or equivalently +.IP +.B wrjpgcom +.B -cfile +.I comment.txt +.B < +.I in.jpg +.B > +.I out.jpg +.SH SEE ALSO +.BR cjpeg (1), +.BR djpeg (1), +.BR jpegtran (1), +.BR rdjpgcom (1) +.SH AUTHOR +Independent JPEG Group |