| Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 1 | .TH WRJPGCOM 1 "15 June 1995" |
| Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 2 | .SH NAME |
| 3 | wrjpgcom \- insert text comments into a JPEG file |
| 4 | .SH SYNOPSIS |
| 5 | .B wrjpgcom |
| 6 | [ |
| 7 | .B \-replace |
| 8 | ] |
| 9 | [ |
| 10 | .BI \-comment " text" |
| 11 | ] |
| 12 | [ |
| 13 | .BI \-cfile " name" |
| 14 | ] |
| 15 | [ |
| 16 | .I filename |
| 17 | ] |
| 18 | .LP |
| 19 | .SH DESCRIPTION |
| 20 | .LP |
| 21 | .B wrjpgcom |
| 22 | reads the named JPEG/JFIF file, or the standard input if no file is named, |
| 23 | and generates a new JPEG/JFIF file on standard output. A comment block is |
| 24 | added to the file. |
| 25 | .PP |
| 26 | The JPEG standard allows "comment" (COM) blocks to occur within a JPEG file. |
| 27 | Although the standard doesn't actually define what COM blocks are for, they |
| 28 | are widely used to hold user-supplied text strings. This lets you add |
| 29 | annotations, titles, index terms, etc to your JPEG files, and later retrieve |
| 30 | them as text. COM blocks do not interfere with the image stored in the JPEG |
| 31 | file. The maximum size of a COM block is 64K, but you can have as many of |
| 32 | them as you like in one JPEG file. |
| 33 | .PP |
| 34 | .B wrjpgcom |
| 35 | adds a COM block, containing text you provide, to a JPEG file. |
| 36 | Ordinarily, the COM block is added after any existing COM blocks; but you |
| 37 | can delete the old COM blocks if you wish. |
| 38 | .SH OPTIONS |
| 39 | Switch names may be abbreviated, and are not case sensitive. |
| 40 | .TP |
| 41 | .B \-replace |
| 42 | Delete any existing COM blocks from the file. |
| 43 | .TP |
| 44 | .BI \-comment " text" |
| 45 | Supply text for new COM block on command line. |
| 46 | .TP |
| 47 | .BI \-cfile " name" |
| 48 | Read text for new COM block from named file. |
| 49 | .PP |
| 50 | If you have only one line of comment text to add, you can provide it on the |
| 51 | command line with |
| 52 | .BR \-comment . |
| 53 | The comment text must be surrounded with quotes so that it is treated as a |
| 54 | single argument. Longer comments can be read from a text file. |
| 55 | .PP |
| 56 | If you give neither |
| 57 | .B \-comment |
| 58 | nor |
| Leon Scroggins III | 3993b37 | 2018-07-16 10:43:45 -0400 | [diff] [blame] | 59 | .BR \-cfile, |
| Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 60 | then |
| 61 | .B wrjpgcom |
| 62 | will read the comment text from standard input. (In this case an input image |
| 63 | file name MUST be supplied, so that the source JPEG file comes from somewhere |
| 64 | else.) You can enter multiple lines, up to 64KB worth. Type an end-of-file |
| 65 | indicator (usually control-D) to terminate the comment text entry. |
| 66 | .PP |
| 67 | .B wrjpgcom |
| 68 | will not add a COM block if the provided comment string is empty. Therefore |
| 69 | \fB\-replace \-comment ""\fR can be used to delete all COM blocks from a file. |
| 70 | .SH EXAMPLES |
| 71 | .LP |
| 72 | Add a short comment to in.jpg, producing out.jpg: |
| 73 | .IP |
| 74 | .B wrjpgcom \-c |
| 75 | \fI"View of my back yard" in.jpg |
| 76 | .B > |
| 77 | .I out.jpg |
| 78 | .PP |
| 79 | Attach a long comment previously stored in comment.txt: |
| 80 | .IP |
| 81 | .B wrjpgcom |
| 82 | .I in.jpg |
| 83 | .B < |
| 84 | .I comment.txt |
| 85 | .B > |
| 86 | .I out.jpg |
| 87 | .PP |
| 88 | or equivalently |
| 89 | .IP |
| 90 | .B wrjpgcom |
| 91 | .B -cfile |
| 92 | .I comment.txt |
| 93 | .B < |
| 94 | .I in.jpg |
| 95 | .B > |
| 96 | .I out.jpg |
| 97 | .SH SEE ALSO |
| 98 | .BR cjpeg (1), |
| 99 | .BR djpeg (1), |
| Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 100 | .BR jpegtran (1), |
| Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 101 | .BR rdjpgcom (1) |
| 102 | .SH AUTHOR |
| 103 | Independent JPEG Group |