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1. Adrian Cochrane (alcinnz@floss.social)'s status on Monday, 20-Feb-2023 03:46:59 JST Adrian Cochrane

   FreeType includes a submodule which renders glyphs to "signed distance fields", though I don't know why. Perhaps to aid automatic boldening?

   A renderer class is exposed to the FreeType subsystems infrastructure, mainly consisting of a render method. This method, after initialization & validation, defers to another method & cleans up.

   It also has methods wrapping FT_Outline operations. There's another extremely class with a different render method.

   1/?

   • Adrian Cochrane (alcinnz@floss.social)'s status on Monday, 20-Feb-2023 04:12:00 JST Adrian Cochrane

     in reply to

     Then there's methodtables for getting/setting named properties.

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     There's utilities for computing square roots, converting 16.16 fixedpoint numbers to a given integral range, & invert signs.

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     In another file a similar class has a render method which appears to actually the core logic! After validation & initialization for the given mode this one applies edge-detection to the bitmap filling in those distance values, then runs 4 passes to propagate these distances in each direction.

     2/3?

   • Adrian Cochrane (alcinnz@floss.social)'s status on Monday, 20-Feb-2023 04:22:30 JST Adrian Cochrane

     in reply to

     A last iteration finalizes the results into the desired format, & square-roots them. Otherwise I'm sure that square-root could become a bottleneck. Then cleans up.

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     Alternate core logic applies fancier but less memory-intensive calculations to glyph outlines. After its initialization & validation it runs the standard decomposition operation, & chooses a codepath based on whether there's overlaps.

     I'll discuss these tomorrow!

     3/3 For now!