Resource Handling

A resource in Zircon is an asset which comes from an external source (an .xp file for example). Zircon handles several types of resources, you can check the resource package here if you want to see details.

A resource usually has a helper class and comes with some static methods which help you load the given resource by hand. Most of them have enum values which will give you some built-in resources (like CP437 tilesets). See more details below.


Zircon handles multiple types of tilesets. Currently there is support for graphic, image, CP437 and true type tilesets.

CP437 tilesets

CP437 tilesets come in the form of transparent .png files. You can peruse [BuiltInCP437TilesetResource] to check the details. The rules of using CP437 tilesets:

  • Your .png file has to have a transparent background
  • You are free to use the built-in CP437 fonts as you see fit (they come from the Dwarf Fortress Tileset Repository and from REXPaint
  • Your .png file must be a sprite composed of 16x16 character images depicting all CP437 tiles

You can use the built in CP437 tilesets by using the helper class:

import org.hexworks.zircon.api.CP437TilesetResources;
import org.hexworks.zircon.api.resource.CP437TilesetResource;

public class UsingCP437Tilesets {

    public static void main(String[] args) {

        CP437TilesetResource tileset = CP437TilesetResources.rogueYun16x16();


Loading your own TilesetResource is also simple, you just have to provide a width, a height, and an InputStream which points to your file:

CP437TilesetResource.loadCP437Tileset(16, 16, stream);

Graphical tilesets

Graphic tilesets are a bit more complex and they come with their own format (currently a .zip file containing your tile files and some metadata). Check how the NETHACK tileset example looks like here.

You can use the built-in NETHACK tileset like this:

GraphicTilesetResource.NETHACK_16X16.toFont(new PickFirstMetaStrategy());

Or you can load your own .zip file by using GraphicTilesetResource.loadGraphicTileset like this:

GraphicTilesetResource.loadGraphicTileset("path/", new PickFirstMetaStrategy())

What is a MetadataPickingStrategy you might ask?

The Zircon Tileset format

The tileset format which is supported by Zircon is a .zip file which must contain a tileinfo.yml which is the metadata about each tile and at least one .png file which contains the tiles. tileinfo.yml looks like this:

# Nethack tileset ported to the Zircon tileset format
name: Nethack                             # The name of the tileset
size: 16                                  # The size of a tile (only square tiles are supported right now)   
files:                                    # A list of the files in this tileset
  - name: tiles.png                       # name of a file
    tilesPerRow: 40                       # The number of tiles in each row of the file
    tiles:                                # A list of **all** the tiles in this file
      - name: Giant ant                   # The name of the tile
        tags: [animal, ant, giant]        # Optional. All unique words in name will be saved as tags ('giant' and 'ant' in this case
        char: a                           # Optional. If not present the first character of the name will be used
        description: It is big.           # Optional. If not present it will be empty
      - name: Killer bee

These are the rules you have to follow when you work with the Zircon Tileset Format (ZTF in short):

  • There must be a list entry for each .png file you put in your .zip file
  • You must specify the number of tiles per row for each .png file
  • There must be a name for each tile in a tileset file (.png)
  • tags, char and description are optional (see the example above).

If the char is not present the first character of the name will be used. All unique words in name will be saved as lower case tags (giant and ant in Giant ant for example). Description will be empty by default.

Metadata picking strategy

When Zircon tries to draw a TextCharacter on the screen it needs to fetch a texture for that character. In the case of Physical and CP437 fonts this is easy since there is a 1:1 mapping to each texture.

In graphic tilesets however each tile has a name and some tags so it is no longer a straightforward mapping. This is why you can set tags for each TextCharacter. They will be used as filters to figure out which tile to choose from a graphic tileset. This is how it works:

  • Zircon will try to fetch a texture for a TextCharacter based on its char value (eg: x)
  • If there are more than 1 textures it will use the tags from TextCharacter to filter for a match. Note that a texture is only considered if it has all the tags from TextCharacter. So for example if you TextCharacter has tags (foo and bar) and your tile has bar it won’t be considered, but if your tile has (foo, bar and baz) it will be a match.

If there is still more than one option to choose from Zircon will use the MetadataPickingStrategy you supplied to pick one tile. There are two built-in strategies, but you can write your own:

  • PickFirstMetaStrategy <– this will pick the first tile from the list. Good option if you don’t care or if you always want to see the same tile
  • PickRandomMetaStrategy <– this will pick a random tile form the matches. Good if you want varied tiles (like walls for example)

Note that if there is no match found for a set of tags Zircon will throw an exception!

REXPaint files

You can load REXPaint files (.xp) by using RexPaintResource.

Any REXPaint file is supported (even layered ones). You can load your file by calling REXPaintResource.loadREXFile like this:

InputStream is = getClass().getResourceAsStream("/rex_files/cp437_table.xp");
REXPaintResource rex = REXPaintResource.loadREXFile(is);

once you loaded your .xp file it can be converted to Zircon Layers by using toLayerList like this:

List<Layer> layers = rex.toLayerList();

Read more about Layers here.

There is also a complete example which you can try out here.

Color Themes

ColorThemes are special kind of resource, and they are detailed here.


Animations come with their own file format (.zap = Zircon Animation Package). Animations are a beta feature and you can read more about them here.

Do you have questions? Ask us on our Discord Server.