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  • Hi! Recently we've been really pushing up against the limits of what we can fit in Bangle.js's firmware (not helped by ~90k of Tensorflow!). One of the big blobs that takes up space in Bangle.js is actually the vector font (5kB), and I've been itching to try and find a way to improve it as it doesn't look great at the moment.

    There's an issue on GitHub open for it at­ues/1721

    But basically it boils down to:

    Use a Hershey font

    These are old-school vector fonts designed for plotters. It seems they could be packed into about a 1.5kB of flash, and would scale down really nicely. The gotcha is we'd need a way to draw lines bigger than 1 pixel wide, and they won't render very quickly because it's not easy to fill large areas.

    Design our own vector font

    I'm imagining a filled font where each character was:

    • in a 16x16 grid (lets us pack XY into one byte, and will scale down to 16px high).
    • A single polygon (such that we can pass it into the existing draw routines)

    We could just have an SVG file and a write a script to extract the data from it.

    I'd tried to export existing fonts, but we're pretty limited in what we can get in such a small footprint (see the GitHub issue) so I think we need something that embraces the limitations (ie polygons rather than smooth).

    Would anyone be up for giving this a try? I uploaded my rough and ready test SVG file here - I reckon something in that form would be great - realistically for now it only needs to be the top half as well.

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