## Categories

### What is a category?

A category is a container for units. Categories are length, area, volume, etc. If you want to add, modify or delete categories simply edit `Installationdirectory/data/lists/categories.list`

Alternatively you can set up a filter for categories.

### Description of the category-file

The file "`categories.list`" located in subfolder "`data/lists/`" is used to identify categories. Each line represents such a identification. Delete a line to get rid of a category or add a line to add a category. Empty lines and lines with a leading hash (#) will be ignored. The order of conversions is dependent on your definition in the file "`categories.list`".

### Format of each line

Each token is separated by a double colon. Each line must have at least the "`ID`" token. This is the full format:
`ID:Significant Figures:Logic:Comment`

### Description of the tokens

`ID`
the ID represents a filename (without suffix) and it is used to identify the category and an image.

The image
You have to provide "`data/images/sections/ID.png`" in the installationdirectory. Only png is supported. The program supports only png because jpg is too bad for little graphics and gif provides only 8 Bit color depth. If you don't provide an image only text will be shown.

The category
You have to provide "`data/units/ID.list`" in the installationdirectory. Click here to get more information about the unit's data.

Description of the units
You have to provide an suitable entry called "`Category.ID=description`" to a property file. This file can be identified as "`data/lang/categories*.properties`". The exact name of the file is dependent on the actual language selection.

Special conversions
Currently the application supports 12 build-in conversions. They can't be changed without programming. Click here to get more information about these modules.

`Significant Figures`

This token is optional. It defines the significant figures. The default value is 12.
Valid values are: "0, 1, 2, ..., 1000, -". The Hyphen "-" means that the value can't be real.

`Logic`

"true" and "false" are valid values. This token defines the logic of the conversion.

true
It's easier to say one kilometer equals 1000 meter than to say a meter equals 0.001 kilometer. For the most conversions "true" is the better value.

Another example (logic "true")
- 1 byte equals 1 byte
- 1 bit equals 0.125 byte
- 1 kilobyte equals 1024 byte

false
The value "false" for this token is usual for exchange rates, such as Euroland. It's easer to say one "Deutsche Mark" equals 1.95583 Euro, than to say one Euro equals 0.51129188... Deutsche Mark.

Another example:
- 1 byte equals 1 byte
- 1 byte equals 8 bit
- 1 byte equals 1/1024 kilobyte