wrjpgcom - insert text comments into a JPEG file
wrjpgcom [-replace] [-comment text] [-cfile name] [filename]
wrjpgcom reads the named JPEG or JFIF file, or the standard input if no file is named, and generates a new JPEG or JFIF file on the standard output. A comment block is added to the file.
The JPEG standard allows "comment" (COM) blocks to occur within a JPEG file. Although the standard does not actually define the intended function of COM blocks, they are widely used to hold user-supplied text strings. This enables you to add annotations, titles, index terms, and so on to your JPEG files, and later retrieve the COM blocks 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 many COM blocks in one JPEG file.
wrjpgcom adds a COM block, containing text that 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.
The following options are supported:
-cfile name Read the text for a new COM block from the named file.
-comment text Supply the text for a new COM block on the command line.
-replace Delete any existing COM blocks from the file.
The following operands are supported:
filename The name of the JPEG file to which you want to add text comments.
To add only one line of comment text, use the -comment option to provide the text on the command line. Specify the comment text within quotes, so that the text is treated as a single argument. Longer comments can be read from a text file.
If you specify neither the -comment nor the -cfile option, wrjpgcom reads the comment text from standard input. In such cases, you must supply an input image filename. You can enter multiple lines, up to 64KB. Type an end-of-file indicator, usually Ctrl-D, to terminate the comment text entry.
wrjpgcom does not add a COM block if the provided comment string is empty. Therefore, you can use -replace -comment "" to delete all COM blocks from a file.
Example 1: Adding a Short Comment to in.jpg to Produce out.jpg
example% wrjpgcom -c "View of my back yard" in.jpg > out.jpg
Example 2: Attaching a Long Comment Previously Stored in comment.txt
example% wrjpgcom in.jpg < comment.txt > out.jpg
example% wrjpgcom -cfile comment.txt < in.jpg > out.jpg
In this example, 1000 is a number that is larger than the number of rows in the source file.
See attributes(5) for descriptions of the following attributes:
ATTRIBUTE TYPE ATTRIBUTE VALUE Availability SUNWjpg Interface stability Volatile
cjpeg(1), djpeg(1), jpegtran(1), rdjpgcom(1)
This man page was originally written by the Independent JPEG Group. Updated by Breda McColgan, Sun Microsystems Inc., 2004.
|SunOS 5.11||wrjpgcom (1)||26 Mar 2004|