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This repo will remain as an archive, but won't receive any updates.

abfi

Allegro Bitmap Font Importer plugin for Godot 4.x.

For Godot 3.x, use abfi v1.3.0.

abfi provides an importer for FontFile resources from plain PNG images. It aims to implement Allegro's al_grab_font_from_bitmap in Godot.

Like the included monospaced bitmap font importer, this allows you to create bitmap fonts in a normal image editor – but without the limitation of monospacing. No BMFont required either!

Installation

From GitLab

• Download the source from the latest tag.
• Extract the addons/ directory into your Godot project.
• Enable the plugin in your project's settings.

From the Asset Library

• From the 'AssetLib' tab in Godot, search 'abfi'.
• Download the plugin.
• When prompted, select only the addons/ directory.

Image format

Let's explain this by example. Here's a valid (albeit tiny) PNG pixel font for the glyphs 123 and ABC:

Now, let's look at how the importer interprets it. Here's that image scaled-up:

• The top-leftmost pixel defines the delimiter colour. Every outside pixel in the image must also be this colour.
  • In the PNG above, the delimiter colour is mid-grey (#7f7f7f).
  • This shouldn't be transparent. Instead - unlike the above - your glyphs should have transparent backgrounds. Otherwise the backgrounds will be drawn too! We've just used black so you can see it on the page.
• Glyphs are read in left-to-right, then top-to-bottom.
  • You'll probably want to arrange the glyphs in their Unicode ordering; you'll see why below.
• Glyphs can vary in width, but must be the same height.
• Every row of glyphs must be separated by a horizontal line with the delimiter colour.
• It's fine to put as much delimiter colour padding as you like between glyphs on the same row.

Even with all of the above, the importer still doesn't know which glyphs correspond to which characters. This leads us onto...

Plugin options

Select a PNG image in the 'FileSystem' tab, then select the 'Import' tab.

Then, select 'Font data (Allegro)' from the dropdown:

Each string in 'Ranges' defines an inclusive range of Unicode characters to import from the image, separated by a -. So, in the above screenshot, 123 and ABC are imported - meaning these settings would correctly import the font we described above.

Importing single characters

If you're using a single wacky Unicode character somewhere, just type that character as the range (don't use a -). The example shown at the top of the page uses this to import an ellipsis by itself.

Letter spacing

This is useful for padding out characters or pushing them together (if set to a negative value). The latter is especially useful for reducing the spacing on fonts which have an outline:

Mipmaps

Enables texture mipmaps. This is useful for larger fonts, but not for pixel fonts. Leave this unchecked if you aren't sure.

Wrapping it up

Once everything's configured, hit 'Reimport'. Hopefully, that should be it, and you can now use your PNG as a font!

Keep an eye on the console for errors; if the image isn't correctly formatted - or your the number of glyphs specified doesn't match it - you'll be warned about it there.

Note: apologies, I'm aware the interface here is a bit janky. It doesn't seem possible to provide detailed property hints for importer options at the moment.

Development

Currently, there are no unit tests. If this plugin gets any bigger, Gut may be employed.

Release procedure

• Manually test:
  • Copy addons/abfi into a fresh Godot project, and load the example font.
  • Ensure successful import for the example ranges: 1-3, A-C.
  • Ensure an 'underflow' error is shown for 2-3, A-C.
  • Ensure an 'overflow' error is shown for 1-3, A-D.
  • Check letter spacing works as expected (both positive and negative).
  • Check the mipmaps option works as expected.
• Bump the version in addons/abfi/plugin.cfg.
  • Commit with message vX.Y.Z.
  • Add a tag, also vX.Y.Z.
  • Note the commit hash.
• Edit the asset, updating the commit hash.

License

ISC