29 lines
2.1 KiB
Markdown
29 lines
2.1 KiB
Markdown
# allegro_schrift
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Drop-in replacement for Allegro_TTF that contains libschrift, instead of using FreeType2.
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It is 100% API compatible with the vanilla TrueType addon. Compile Allegro with these files inside of `/addons/ttf`.
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Requires the primitives addon.
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## Pros
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- It doesn't require NT 6 kernel calls
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- It doesn't dynamically link against hundreds of thousands of lines of ugly corporate-backed C code you can't read
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- Our addon is only a couple or few hundred lines, and libschrift is less than 2,000. They're compiled together.
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The original Allegro_TTF is over 1,000 lines (for a good reason) and has a relatively massive dependency weight (for a stupid reason).
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## Caveats
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- Pre-stretching is not implemented.
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- The entire caching system is gone, fonts are baked to textures immediately and no further. This makes supporting some languages with this add-on inconvenient, and increases load times. For many users this an acceptable tradeoff.
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- The `cache_text` setting in allegro5.cfg is now reused to determine what glyphs can be rendered at all. `skip_cache_misses` has no effect.
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When `cache_text` is undefined, the [Latin](https://en.wikipedia.org/wiki/ASCII), [Germanic, and Romance](https://en.wikipedia.org/wiki/Latin_Extended-A) alphabets will be generated by default. (not necessarily 32 - 255)
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- **TODO** Alternatively, the developer can force a custom range of unicode characters to be generated using a new parameter in the `al_load_ttf_font` function.
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- Kerning, per-character advance and offsets, and other features which are exposed by libschrift are not currently implemented, but doing so is possible. See the above comparison screenshot.
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## In Practice
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You can see here some of the flaws with this implementation. Line heights are taller than they should be, and there's an issue with string endings or other characters.
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Not visible in the below example is the atlas size to hold glyph data.
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