nyancat

commit 41cefd3da9852be69c40139eda82ed24b7a59d31
parent 27ed7c32a15c28ff85a91f55190972b00d1fbcac
Author: Santtu Lakkala <inz@inz.fi>
Date:   Mon, 20 Jul 2020 10:48:59 +0300

Implement 256 and 16 color modes

Diffstat:
M
nyancat.c
 | 
119
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--------

1 file changed, 107 insertions(+), 12 deletions(-)
diff --git a/nyancat.c b/nyancat.c
@@ -48,6 +48,7 @@ struct lolcat {
 	bool was_bold;
 	bool was_reverse;
 	bool was_underline;
+	enum { TRUECOLOR, INDEXED256, INDEXED16 } mode;
 
 	void (*write)(const char *buffer, size_t buflen, void *data);
 	void *write_data;
@@ -137,6 +138,7 @@ struct lolcat *lolcat_init(void (*write_cb)(const char *buffer, size_t buflen,
 	rv->write_data = cbdata;
 	rv->fg = 0xc0c0c0;
 	rv->bg = 0x000000;
+	rv->mode = TRUECOLOR;
 
 	return rv;
 }
@@ -222,6 +224,52 @@ static int _add(int a, int b, double amount)
 		CLAMP(bl, 0, 255);
 }
 
+static inline uint8_t absd(uint8_t a, uint8_t b)
+{
+	if (a > b)
+		return a - b;
+	return b - a;
+}
+
+static inline int _index16(uint32_t col, bool *bright)
+{
+	uint8_t r = col >> 16;
+	uint8_t g = (col >> 8) & 255;
+	uint8_t b = col & 255;
+
+	uint8_t ri = ((uint16_t)r + 64) * 2 / 256;
+	uint8_t gi = ((uint16_t)g + 64) * 2 / 256;
+	uint8_t bi = ((uint16_t)b + 64) * 2 / 256;
+
+	if (ri == 2 || gi == 2 || bi == 2) {
+		ri = r > 127U;
+		gi = g > 127U;
+		bi = b > 127U;
+		*bright = true;
+	} else {
+		*bright = false;
+	}
+
+	return ri | bi << 1 | gi << 2;
+}
+
+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;
+
+	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))
+		return cr * 36 + cg * 6 + cb + 16;
+	return g + 232;
+}
+
 static void _lc_colorize(struct lolcat *lc, const char *u8_char, size_t len)
 {
 	char buffer[128] = "\x1b[";
@@ -234,6 +282,17 @@ static void _lc_colorize(struct lolcat *lc, const char *u8_char, size_t len)
 		return;
 	}
 
+	if (lc->bold)
+		col = _bold(lc->fg);
+	else
+		col = lc->fg;
+	col = _add(rainbow(0.03, nyan(lc->x, lc->y)), col, 0.5);
+
+	if (lc->mode == INDEXED16)
+		col = _index16(col, &lc->bold);
+	else if (lc->mode == INDEXED256)
+		col = _index256(col);
+
 	if ((lc->was_bold && !lc->bold) ||
 	    (lc->was_reverse && !lc->reverse)) {
 		lc->was_underline = false;
@@ -260,16 +319,17 @@ static void _lc_colorize(struct lolcat *lc, const char *u8_char, size_t len)
 		lc->was_reverse = true;
 	}
 
-	if (lc->bold)
-		col = _bold(lc->fg);
+	if (lc->mode == INDEXED16)
+		bw += sprintf(bw, "3%dm%.*s",
+			      col, (int)len, u8_char);
+	else if (lc->mode == INDEXED256)
+		bw += sprintf(bw, "38;5;%dm%.*s",
+			      col, (int)len, u8_char);
 	else
-		col = lc->fg;
-	col = _add(rainbow(0.03, nyan(lc->x, lc->y)), col, 0.5);
-
-	bw += sprintf(bw, "38;2;%d;%d;%dm%.*s",
-		      col >> 16,
-		      (col >> 8) & 255,
-		      col & 255, (int)len, u8_char);
+		bw += sprintf(bw, "38;2;%d;%d;%dm%.*s",
+			      col >> 16,
+			      (col >> 8) & 255,
+			      col & 255, (int)len, u8_char);
 
 	lc->write(buffer, bw - buffer, lc->write_data);
 }
@@ -489,13 +549,19 @@ void lolcat_set_size(struct lolcat *lc, int w, int h)
 	lc->h = h;
 }
 
+static void usage()
+{
+	fprintf(stderr, "Usage: nyancat [-t2] [file...]\n");
+	exit(0);
+}
+
 int main(int argc, char **argv)
 {
 	struct lolcat *lc = lolcat_init(_write, stdout);
 	char buffer[2048];
 	size_t used = 0;
 	struct termios old_tio = { 0 }, new_tio;
-	int i;
+	int i = 1;
 
 	struct winsize ws = { 0 };
 
@@ -503,7 +569,36 @@ int main(int argc, char **argv)
 	    !ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws))
 		lolcat_set_size(lc, ws.ws_col, ws.ws_row);
 
-	if (argc < 2) {
+	while (i < argc) {
+		const char *opt;
+		if (argv[i][0] != '-' || argv[i][1] == '\0')
+			break;
+		if (argv[i][1] == '-' && argv[i][2] == '\0') {
+			i++;
+			break;
+		}
+		opt = &argv[i++][1];
+
+		while (*opt) {
+			switch (*opt++) {
+			case 't':
+				lc->mode = TRUECOLOR;
+				break;
+			case '1':
+				lc->mode = INDEXED16;
+				break;
+			case '2':
+				lc->mode = INDEXED256;
+				break;
+			case 'h':
+			default:
+				usage();
+				break;
+			}
+		}
+	}
+
+	if (i >= argc) {
 		tcgetattr(STDIN_FILENO, &old_tio);
 
 		new_tio = old_tio;
@@ -533,7 +628,7 @@ int main(int argc, char **argv)
 		fflush(stdout);
 		tcsetattr(STDIN_FILENO, TCSANOW, &old_tio);
 	} else {
-		for (i = 1; i < argc; i++) {
+		for (; i < argc; i++) {
 			int fd;
 			if (!strcmp(argv[i], "-"))
 				fd = STDIN_FILENO;