Smoother non-antialiased default font for LVGL

[bwhitman]

I am annoyed by the way the default LVGL fonts look on Tulip, since we're not using antialiasing.

We should convert our other bitmap proportional fonts back into LVGL. they look cleaner without AA.

Screenshot of the current fonts:

[bwhitman]

This is kind of a pain. I've tried

• Using the online TTF converter for fonts -- this really only looks good if the TTF was originally a bitmap font, and it's hard to find a cache of these somewhere online -- if anyone's got a good source of proportional sans-serif bitmap TTF fonts, let me know
• Turning on antialiasing -- this is noticeably slower and doesn't really look good on the 7" Tulip, probably because of RGB332 and the larger DPI
• Tools like bdf2lvgl or bdf2ttf , all are quite old and have various bugs with the known good u8g2 bdfs
• Most promising, i've found that LVGL lets you set your own font renderer -- this would let me use the BDF u8g2 Tulip fonts already burned into flash as LVGL fonts. Not surprisingly, the docs for this feature are not up to date with LVGL9 (a common theme) but i have a stub working and will try to see this through. It's the most "tulip-y" solution, as we'll have the most control over the fonts we ship and how they're drawn.

[bwhitman]

I eventually, and with much pain, built a U8G2 to LVGL converter. I'll share this with the LVGL community soon, i think it's helpful for lots of others. There's still some small bugs but it mostly works and we now have a pixel-perfect helvetica 12 font as our default font in Tulip.

[bwhitman]

Merged this. Going to call it done and log any issues we see with it!

[bwhitman]

Re-opening, too many bugs. Will merge in the glyph bug in here too. I'll work on this on a separate branch

[bwhitman]

Tulip font 11, which is U8G2 u8g2_font_crox1h_tr, is our current proportional small default pixel font. It (or others) cannot render -, *, or ' so far, which is odd. This is either a rendering bug (straight lines?) or something missing in the font.