nyancat

commit 2abf293ba0c01cd37dac3c93e34258f6cda3f977
parent ad27f9f67f3dc20c756d9c99c05b14fcf48bc84a
Author: Santtu Lakkala <inz@inz.fi>
Date:   Mon, 20 Jul 2020 14:39:00 +0300

Fix 256 color output

Diffstat:
M
nyancat.c
 | 
20
+++++++++++++-------

1 file changed, 13 insertions(+), 7 deletions(-)
diff --git a/nyancat.c b/nyancat.c
@@ -258,16 +258,22 @@ static inline int _index256(uint32_t col)
 	uint8_t r = col >> 16;
 	uint8_t g = (col >> 8) & 255;
 	uint8_t b = col & 255;
-	uint8_t cr = r < 28 ? 0 : (r - 28) * 5 / 228 + 1;
-	uint8_t cb = b < 28 ? 0 : (b - 28) * 5 / 228 + 1;
-	uint8_t cg = g < 28 ? 0 : (g - 28) * 5 / 228 + 1;
 
-	uint8_t gs = ((uint16_t)r + g + b) / 3 * 32 / 256;
+	uint8_t cr = r < 35 ? 0 : (r - 35) / 40;
+	uint8_t cb = b < 35 ? 0 : (b - 35) / 40;
+	uint8_t cg = g < 35 ? 0 : (g - 35) / 40;
 
-	if (absd(cr * 40 + !!cr * 55, r) + absd(cg * 40 + !!cg * 55, g) + absd(cb + 40 + !!cb * 55, b) <
-	    absd(gs, r) + absd(gs, g) + absd(gs, b))
+	uint8_t gs = (0xee - ((uint16_t)r + g + b) / 3) / 10;
+
+	if (gs > 23 ||
+	    absd(cr * 40 + !!cr * 55, r) +
+	    absd(cg * 40 + !!cg * 55, g) +
+	    absd(cb + 40 + !!cb * 55, b) <=
+	    absd(0xee - 10 * gs, r) +
+	    absd(0xee - 10 * gs, g) +
+	    absd(0xee - 10 * gs, b))
 		return cr * 36 + cg * 6 + cb + 16;
-	return g + 232;
+	return 255 - gs;
 }
 
 static void _lc_colorize(struct lolcat *lc, const char *u8_char, size_t len)