Revision as of 13:24, 3 May 2023 (view source) Chemoelectric (talk \| contribs) (→‎The ATS static file) ← Older edit		Revision as of 13:25, 3 May 2023 (view source) Chemoelectric (talk \| contribs) (→‎The ATS dynamic file) Newer edit →
Line 395: implement {} rgb24_to_gray8 rgb = (* There is no need for floating point here, although equivalent integer calculations are a bit longer to write out. ) let extern castfn ~~u8_to_dbl~~i2u32 : ~~uint8~~int -<> ~~double~~uint32 extern castfn ~~dbl_to_u8~~u8_to_u32 : ~~double~~uint8 -<> ~~uint8~~uint32 extern castfn u32_to_u8 : uint32 -<> uint8 val @(r, g, b) = rgb24_values rgb val r ~~: double~~ = ~~u8_to_dbl~~u8_to_u32 r and g ~~: double~~ = ~~u8_to_dbl~~u8_to_u32 g and b ~~: double~~ = ~~u8_to_dbl~~u8_to_u32 b val Y = (0.i2u32 2126 r) + (0.i2u32 7152 * g) + (~~0.0722~~i2u32 722 * b) val YiY1 = ~~dbl_to_u8~~Y ~~($extfcall~~/ ~~(double,~~i2u32 ~~"rint", Y))~~10000 and Y0 = Y mod (i2u32 10000) in if Y0 < i2u32 5000 then gray8_make Yi(u32_to_u8 Y1) else if i2u32 5000 < Y0 then gray8_make (succ (u32_to_u8 Y1)) else if Y0 mod (i2u32 2) = i2u32 0 then gray8_make (u32_to_u8 Y1) else gray8_make (succ (u32_to_u8 Y1)) end

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