I fixed a bug where atrazine would leave the terminal dirty in case it is interrupted by a signal.
LATEST VERSION
Source
// compile with: gcc atrazine.c -o atrazine -lm -O2 -Wpedantic -Wall -Wextra
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#define CSI "\033["
#define RESET CSI"m"
void cleanup(void) {
printf(RESET);
}
void rainbow(float phase) {
printf("%s38;2;%d;%d;%dm", CSI,
/* red */ (int) (sinf(phase + 0 ) * 127 + 128),
/* green */ (int) (sinf(phase + 2*M_PI/3) * 127 + 128),
/* blue */ (int) (sinf(phase + 4*M_PI/3) * 127 + 128)
);
}
inline int is_UTF8_continuation(char c) {
return (c & 0xc0) == 0x80;
}
/* state machine that detects ANSI escape sequences, somewhat poorly */
int in_ANSI(char c) {
static int state = 0;
if (state && (isalpha(c) || c == '~' || c == '\033')) state = 0;
if (c == '\033' && !state) state = 1;
return state;
}
int main() {
float omega = 0.05f;
int nl_offset = 3, t = 0, line = 0;
char c, peek;
atexit(cleanup);
rainbow(omega * t);
while ((c = getchar()) != EOF) {
peek = getchar();
ungetc(peek, stdin);
if (c == '\n') {
t = 0;
line++;
printf(RESET);
}
printf("%c", c);
if (!is_UTF8_continuation(peek) && !in_ANSI(c)) {
rainbow(omega * ((++t) + nl_offset * line));
}
}
}
Also, angular frequency is adjusted to make a bigger, smoother rainbow. I should probably randomise it in a later version…
