Preamble
The Small Font Format is intended for use in embedded applications, where a small font is required. The format is monochrome only, and will remain so for the foreseeable future. In its first iteration, the format supports only 8x8 character sizes. However, 4 bytes have been reserved in the header to allow for future expansion, which could perhaps include support for variable size fonts.
Edit 2023-06-14: Relevant XKCD - Standards, I’m fairly certain someone else has already done this. I’d probably be better off adapting FBConsole to use the existing standard. And yet, here we are.
Version history
| Version | Notes |
|---|---|
| v1.0 | Initial release |
Version history
File format
Header - 8 bytes
| Offset | Length | Description | Expected value |
|---|---|---|---|
| 0x00 | 3 bytes | Magic header | 53 46 46 |
| 0x03 | 1 byte | Format version | 10 |
| 0x04 | 4 bytes | Reserved | 00 00 00 00 |
Header format
- Magic Header - The 3 bytes
53 46 46represent “SFF” in ASCII. - Version - The first nibble of this byte represents the format’s major version, the second nibble represents the format’s minor version.
- Reserved - Reserved for future expansion. See preamble.
Character data - 96 * 8 bytes
Each block of 8 bytes represents a bitmap describing how to draw a character, where the left most bit in each byte represents the left most column. Each row is represented by a single byte, with the first byte representing the top row.
In its first iteration, the format requires 96 characters to be defined. These represent ASCII codes 0x20 - 0x7E - this is the first 95 characters in the format. Character 96 should be used by a character renderer to represent bytes passed to it, which fall outside defined range. The font designer may choose to represent this with a symbol, or leave it blank.
Supporting tools
Coming soon - a tool to edit Small Font Format fonts, using WinForms on .Net 4.0. However, I don’t expect this to be the de facto editor for Small Font Format fonts - I’d like to rewrite this tool with something that allows for native cross platform use. This may be Python or C++, but will use a true cross-platform GUI toolkit.