
  JPG Info v 0.92



ATTENTION: THIS IS BETA SOFWTARE. MAKE A BACKUP OF YOUR JPG FILES BEFORE USE THIS TOOL!



JPG Info comes with the following features:

- displays a thumbnail and the name of a JPG file
Currently it is optimized for speed, not for quality.

- shows JPG comments
A JPG comment is a standardized, text-based META-information, which is embedded in the JPG file.

- allows editing of JPG comments
With the 'apply' button the original JPG file will be backed up, and a new JPG file containing the original JPG data and the entered comments will be created.
The JPG data will be taken over without loss of quality. Also EXIF data will be saved.

Note: the backup file name will be the same filename as the original, but with an appended '.bak', e.g. if your JPG file is named 'C:\JPG\file.jpg', then the backup file will be labeled 'C:\JPG\file.jpg.bak'. 
At this time the backup file will not be deleted automatically. I will add an auto-delete feature after some testing in a later version. If you apply comments twice or more to the same JPG file, the 'JPG Info' will ask your to delete the backup file.

- if available shows the EXIF informations of the JPG file
EXIF data are JPG-embedded META informations, created by a digital camera.
These informations are not editable.

- shows an 'about' information window, containing the used modules and copyright informations.

- display all data in a drag and drop enabled standard PM notebook style.
Drag and drop requires ObjectRexx at this moment.

- works multithreaded.

- free, non-commercial software


  Availability

The latest version of 'JPG Info' may be found at 

http://www.subsys.de/JPGInfo/
(site currently under construction)



  Reqirements

- OS/2 or eComStation with REXX installed.
- ObjectRexx for full drag and drop support (but works without d'n d under classic rexx) 
- JPG06 (included in download archiv)
- RXEXIF.DLL (included in download archiv)



  Installation

 Just unzip the archive to a directory on your harddrive. Make sure that the subdirectory 'jpeg' has been created succesfully. Run install.cmd from a commandline to create objects on your desktop. 
 If 'JPG Info' does not run properly, then copy the following files to C:\OS2\DLL (replace 'C' with your bootdrive)
- ..\JPGInfo\rxexif.dll
- ..\JPGInfo\jpeg\jpeg.dll
(it depends on your system settings, on standard OS/2 and eCs installations this should not be necesary).



  Use

 The tool should be self explained.
To load files, drop JPG files on the JPG Info program object, or if 'JPG Info' already has been started, drop the files on the first notebook page.
 To open the tool from the context menu of JPG files, associate the program object with *JPG and *JPEG using the WPS or assoedit.
To add a comment enter the text in the entry fields on page 2, and then simply press the 'apply' button. There is a history function, with this you are able to recall a list of the last used text strings. Select one and hit 'ok' to take over the string to the corresponding entry field.



  Notes to JPG comments

 JPG comments are generally text based. The main advantage of these informations is, that these informations are embedded directly in the JPG file, so they are object oriented and platform independent. Unlike than informations e.g. written to OS/2s extended attributes or saved in external databases, JPG comments will be keeped when one moves the JPGs on harddisks around or during transmissions of JPGs via email.



  Notes to JPG comments on OS/2 or eComStation using 'JPG Info'

 Normally, a JPG comment is a large text block with multiple lines. There are no differenciated data fields inside the comment. 
But because the JPG comment supports multi-line text, 'JPG Info' goes a very simple way to implement various data fields anyway. In conjunction with the standardized DOC infos in PDF files there are data fields for title, subject (you may add categories here), author (normally the photograph) and additional notes. With the exception of the last field (which is a multi-line field), each data field is one line in the comment. 

 During reading of JPG comments 'JPG Info' recognizes the data fields by scanning the first string of each line. It scans for 'Title:', 'Subject:', 'Author:' and 'Notes:', and if it finds conformability, it assigns the data to the corresponding entry fields in 'JPG Info' window. All unknown data will be added to the last field (notes, multi-line entry field).

 During writing JPG comments, 'JPG Info' adds the header strings 'Title:', 'Subject:' and 'Author:' and 'Notes:' automatically to the file.

By this way, 'JPG Info' on OS/2 and eCs comes with an advantage over the pendants on other platforms, but is completely compatible.



  JPG comments on other applications

Both, JPG comments and EXIF are not supported by all applications. In worst case, a bitmap manipulation program will destroy the data during saving a file. So beware! If you want to manipulate your JPGs with a program that does not support JPG comments and EXIF, then work only with a copy of your JPG and keep the original on a save place.
 So far I know on OS/2 only one prgram supports JPG comments and EXIF: PMViewPro. It is also able to display JPG comments written by 'JPG Info'. Look at 
http://www.pmview.com 
 Applications like Embellish, Faxview or Impos/2 will strip all META informations during saving, the data will be lost. So don't forget to make a backup file before saving. 



  Reading and writing JPG comments on other platforms

 Windows:
There is a little tool called 'edjpgcom', which is able to display and edit this kind of comments. 
http://home.cfl.rr.com/maderik/edjpgcom/ 
Note: the maximum comment length on windows is 32 kB.

 Linux:
To read and write comments on Linux, use the commandline tools RDJPGCOM (read) and WRJPGCOM (write).
For more information, you may visit this web pages:

http://linux.about.com/library/cmd/blcmdl1_wrjpgcom.htm
http://linux.about.com/library/cmd/blcmdl1_rdjpgcom.htm


 Both, Linux and Windows tools are using the same code of the 'Independent JPG Group' to read and write the comments:

http://www.ijg.org/files/

'JPG Info' for OS/2 uses this code, too.



  License

 We allow you to use and distribute this files freely under the condition that we are in no way responsible for any damage or loss you may suffer.




Frank Wochatz
Berlin, 03. May 2005



History

v 0.92
- fixed: SYS 1041 error (while opening files) 

v 0.91
- new: EAs will be saved (importent e.g. to keep PMView thumbnails alive)
- new: date and time stamp will be saved (last write access) 
Note: this feature requires REXXUTIL.DLL in version from 18 May 1999 or later

- fixed: error text for non-object rexx sueres corrected

v 0.90
- Fist public version