Questions and answers about Jomic

Thomas Aglassinger

$Id: faq.xml 2200 2011-04-25 15:16:40Z roskakori $

Table of Contents

General Questions
What rocks about Jomic?
What sucks about Jomic?
Does it work with Mac OS Classic?
Does it work with with my hand held or cell phone?
Oh boy. Are there any other viewers?
Troubleshooting
Why are some images of a comic displayed in wrong order? In particular, all the landscape images are shown at the end.
Jomic can not open an archive
Jomic can not display an image
When launching Jomic, it says "Cannot launch Java application" and something about "splash.jpg" (Mac OS X)
When launching Jomic, the JavaApplicationStub crashes (Mac OS X 10.3.9)
Questions about comic book archives
What are CBZ, CBR and PDF comic book archives?
How can I create comic book archives myself?
Why should I not use RAR for creating comic book archives?

General Questions

The main features where Jomic distinguishes itself from many other viewers are:

Ok, you asked for it, so here's the rant:

No.

Mac OS Classic 9.x only supports Java 1.3, Mac OS Classic 8.x only Java 1.1. Jomic requires Java 1.4 or later.

You can try Jimic, which is a stripped down version of Jomic satisfied with Java 1.1 and working with Mac OS Classic 8.0 or later. It only supports CBZ/ZIP comics, so you have to convert CBR/RAR comics before you can read them, though.

Most likely not.

Todays Java compatible hand helds and cell phones only support the Java 2 Micro Edition (J2ME), which is a wildly stripped down and simplified version compared to Java 1.4. Think Mac OS X vs. Mac OS 7 or Windows XP vs. Windows 3.1 to get the idea.

Some hand helds seem to support Java 1.1, so you might give Jimic a try.

There are plenty of other viewers. For starters, try one of these:

Apart from that, your favourite search engine will reveal serveral others.

Troubleshooting

This happens when you improperly name landscape images. For example the image for page 23 and 24 should be named page_23+24.png instead of page_2324.png.

Like the Mac OS X Finder or the Windows explorer, Jomic sorts images "naturally" instead of "asciibetically". This means numbers use their numeric value, so page_2324.png is treated as text "page_" and number 2324, while page_25.png is treated as text "page_" and number 25 and thus sorted before page_2324.png. If properly named page_23+24.png, it is treated as text "page_", number 23, text "+" and number 24 and thus sorted before page_25.png.

Of course it would be possible to change this, but it would break all images lacking leading zeros. For example, the current natural sorting makes sure that an image named page_3 shows up before an image named page_20.png. Using "asciibetical" sorting would break this.

To fix a comic that suffers from this problem, perform the following steps:

  1. Extract the comic archive as described in the section called “What are CBZ, CBR and PDF comic book archives?”.

  2. Fix the image names so they comply to the recommendations described in the section called “How can I create comic book archives myself?”.

  3. Recreate the comic archive with the changed images.

In most cases, this means the archive is broken (though the error messages generated by the Java zip library or the unrar command rarely state that clearly). To validate this, just try to manually extract the archive. See the section called “What are CBZ, CBR and PDF comic book archives?” on how to do that.

In most cases, this means the image is broken. To validate this, extract the archive (see above) and try to open the image in an image viewer. If the image viewer also cannot open the image, or warns that it is broken while opening it, or opens an image where obviously some parts are missing, it is broken. As a remidy, try to open and save it with an image editor that has a repair feature, and then create a new comic book archive with the new image.

Otherwise, it probably is a bug in the Java image decoder for that particular format. In that case, try to save the image in JPEG or PNG format, repack the archive, and try again.

The dialog should say "Cannot launch Java application. Uncaught excaption in main method: java.lang.IllegalArgumentException: cannot read image resource: "/.../splash.jpg". If you check the console log, it should contain a stack trace with the same message, and the root cause: "javax.imageio.IIOException: Can't create cache file!" and "java.io.IOException: Not a directory".

This means that for some reason the cache directory for Java ImageIO is screwed up.

Now it would of course help a lot if ImageIO actually would tell where its cache directory is located. In this early phase of startup (while attempting to show the splash screen), Jomic does not set the directory to its own cache but goes with the default. Normally, this is /tmp. To check this, open Terminal and try to change to this directory:

cd /tmp

If this yields something like

-bash: cd: /tmp: Not a directory

we found the cause of the problem. To repair it, enter the following commands:

cd /
rm tmp
ln -s private/tmp tmp

Check /Applications/Utilities/Console, it should say something like:

crashdump: Unable to determine CPSProcessSerNum pid: 524 name: JavaApplicationStub
crashdump: Started writing crash report to: /Users/me/Library/Logs/CrashReporter/JavaApplicationStub.crash.log

Checking JavaApplicationStub.crash.log should reveal something like:

Command: JavaApplicationStub
Path: /Applications/Jomic.app/Contents/MacOS/JavaApplicationStub
[...]
Exception: EXC_BAD_ACCESS (0x0001)
Codes: KERN_INVALID_ADDRESS (0x0001) at 0xa7531d54

To fix this, follow the instrunctions at http://docs.info.apple.com/article.html?artnum=301380.

Questions about comic book archives

CBZ files are ZIP archives which contain (mostly) image files. If you change the file extension to .zip, you can extract them with any ZIP tool.

CBR files are RAR archives which contain (mostly) image files. If you change the file extension to .rar, you can extract them with any RAR tool.

PDF stands for "portable document format" and specifies a general format for all kinds of documents. They can also be used to contain comics, in which case every page consists of a singel image.

The easiest way is to copy all images in an new direcory, name them properly, zip the directory, and rename it to *.cbz.

The best way to name images is to use a scheme like 01.jpg, 02.jpg, 03+04.jpg, 05.jpg, and so on. Note that the numbers have leading zeros, and images containing two pages separate the numbers with a "+" sign (as in 03+04.jpg). Complying to these rules guarantees that even simple comic viewers will show the images in the order you intended. Otherwise, they might sort for example 12.jpgbefore 3.jpg because they compare the name letter by letter and do not interpret "12" as a number greater than 3.

Your images should use a compressed format such as JFIF/JPEG or PNG. In this case, you can tell the zip tool to not compress them again. This hardly increases the size, but speeds up opening the archive - a lot. If you work at the command line, you can use for example:

zip -0 s00paman-v03-27.cbz s00paman/v03/27/*.jpg

You should prefer ZIP over RAR. See below why.

RAR sucks for at least the following reasons:

RAR does have a few advantages over ZIP, but none of them really matter for comic book archives:

  • RAR archives can be stored in mutiple files, which unrar automatically joins during extract. That's really useful with 1440K floopy disks, but...

  • RAR has a repair function. So does ZIP, and althought it's technically inferior, in practice it does not really matter because the result is the same: you can extract the archive short of one or two images. (For details, see the -F and -FF switches of the command line zip tool.

  • RAR has slightly better compression, which does't really matter as images in are already compressed anyway. Those few bytes saved clearly don't make up for all the trouble RAR causes otherwise.

Summary: For now, use ZIP instead of RAR. On the long run, 7-Zip might become a viable alternative.