Fix alpha blending formula #594
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DHowett
reviewed
Aug 12, 2025
| 0xfff0e100, // BrightCyan | ||
| 0xffffffff, // BrightWhite | ||
| pub const DEFAULT_THEME: [StraightRgba; INDEXED_COLORS_COUNT] = [ | ||
| StraightRgba::from_be(0x000000ff), // Black |
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why from_be sometimes and from_le other times?
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Just whatever I felt like in any given situation. from_be is helpful because it allows you to copy/paste the literal as a CSS color code (which is also in big endian).
DHowett
reviewed
Aug 12, 2025
| @@ -118,7 +118,8 @@ impl Framebuffer { | |||
| DEFAULT_THEME[IndexedColor::Black as usize], | |||
| DEFAULT_THEME[IndexedColor::BrightWhite as usize], | |||
| ], | |||
| contrast_colors: [const { Cell::new((0, 0)) }; CACHE_TABLE_SIZE], | |||
| contrast_colors: [const { Cell::new((StraightRgba::zero(), StraightRgba::zero())) }; | |||
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would this be helped by deriving default or implementing it to return zero
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Unfortunately no, because traits cannot be const and the Rust maintainers have been bickering working on an implementation for const traits since at least 2020. 🥲
DHowett
approved these changes
Aug 12, 2025
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Since
srgb_to_linearis non-linear we can't use it for premultiplied colors.Instead of unpremultiplying them, I simply changed the rest of the app to use
straight alpha and introduced types to ensure we don't mess it up.