/* circles.c - Draw circles whose color depends on the time of day. Jim Blandy - March 1992. Modified by Karl Fogel , 1996. */ #include #include #include #include #include #include #if defined(vms) #include #include #else #include #if defined(USG) || defined(FTIME_MISSING) /* ** If you need to do a tzset() call to set the ** timezone, and don't have ftime(). */ struct timeb { time_t time; /* Seconds since the epoch */ unsigned short millitm; /* Field not used */ short timezone; short dstflag; /* Field not used */ }; #else #include #endif /* defined(USG) || defined(FTIME_MISSING) */ #if defined(BSD4_2) || defined(BSD4_1C) #include #else #include #endif /* defined(BSD4_2) */ #endif /* defined(vms) */ /* On some systems -- DECStations that us the C library distributed * with Ultrix, for example -- [s]rand() has cyclic properties in the * lower bits that cause the worm to get stuck in certain orbits. * Therefore, we use [s]random instead, but #define them so porting to * systems without [s]random is easier. */ #define RANDOM() random () #define SRANDOM(x) srandom (x) /* What is the chance that the worm will jump to another orbit? */ #define JUMP_PROB 2 extern char *strcpy (char *dest, const char *src); extern char *getenv (const char *var); char *progname; char *disp_name = NULL; /* Note: the code is not actually as general as this implies: */ #define NUM_CIRCLES 3 /* From these two, deduce that there a 2-pixel border: */ #define INTERIOR_WIDTH 10 #define BORDER_WIDTH 14 /* These two tell a worm which way to slither. */ #define CLOCKWISE 0 #define COUNTERCLOCKWISE 1 /* This tells a draw_worm() whether to draw its whole body or just the current segment. */ #define FROM_EXPOSURE 1 #define NOT_FROM_EXPOSURE 0 #define SQUARE(x) ((x) * (x)) #define USECSPERSEC (1000 * 1000) /* The amount of time in which the circles should go through their entire cycle, in microseconds - defaults to one hour. */ long long period = ((long long) 60 * 60 * USECSPERSEC); /* A time at which the cycle should be at its starting position. By default, aligned with the hour. */ char *ascii_phase = "12:00"; /* The above, converted to microseconds since the epoch. */ long long phase; Display *disp; int screen; Window root; GC circle_gc, border_gc; Colormap default_cmap; unsigned long circle_pixel; unsigned long border_pixel; /* A worm slithers along in the trough created by the inner and * outer edges of each circle. There are three circles, but only * one trough, because of the way the circles's edges intersect. * * The worm will keep coming to "forks in the road" -- points where * it is simultaneously in the orbits of two different circles. Does * it stay orbiting the current one, or does it get "captured" by the * other one? It flips an N-sided coin, of course. (The worm can * tell when it's at a fork because then it's equidistant from the * centers of the two different circles.) * * Because there are an odd number of circles, the worm will, if left * slithering long enough, eventually get an opportunity to travel in * both directions along every circle. * * But none of this happens unless you pass the "-worm " option. */ struct worm { int *center_x; /* center of worm's image (X) */ int *center_y; /* center of worm's image (Y) */ int length; /* how long a worm izzit? */ int idx; /* index into above arrays */ int radius; /* radius of worm images */ int sol; /* center of worm's orbit (indexes in arrays below) */ int last_sol; /* history for above */ int au; /* radius of worm's orbit */ int direction; /* CLOCKWISE or COUNTERCLOCKWISE */ /* (Hey, I have it on good authority that mixing metaphors does not affect the efficiency of compiled code.) */ /* The centers of the three possible orbits. We store them here because they get regenerated by draw_circle every time, and even though it's unlikely that they would ever change after the first call, we do want to be _sure_ of staying current. */ int sol_x[NUM_CIRCLES]; int sol_y[NUM_CIRCLES]; /* Bookkeeping. */ GC fore_gc, back_gc; Colormap default_cmap; }; #define array_length(array) (sizeof (array) / sizeof ((array)[0])) void give_usage (void); void draw_circles (struct worm *worm, int from_exposure_p); void place_worm (struct worm *worm); void move_worm (struct worm *worm); void draw_worm (struct worm *worm, int from_exposure_p); void tick (struct timeval *t); void set_color (int); int strcmp_abbrev (char *abbrev, char *model); int main (argc, argv) int argc; char **argv; { struct worm *worm = NULL; progname = argv[0]; for (argc--, argv++; argc>0; argc--, argv++) { if (argv[0][0] == '-') { if (strcmp_abbrev (argv[0], "-display") == 0) { if (argc <= 1) give_usage (); disp_name = argv[1]; argc--, argv++; } else if (strcmp_abbrev (argv[0], "-phase") == 0) { if (argc <= 1) give_usage (); ascii_phase = argv[1]; argc--, argv++; } else if (strcmp_abbrev (argv[0], "-period") == 0) { /* The argument to the -period parameter can contain a decimal point. Check it and parse the whole thing. */ char *secs; char *usecs = NULL; char *scan; if (argc <= 1) give_usage (); secs = (char *) alloca (strlen (argv[1]) + 10); secs = strcpy (secs, argv[1]); for (scan = secs; *scan != '\0'; scan++) switch (*scan) { case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': break; case '.': *scan = '\0'; usecs = scan + 1; break; default: give_usage (); } /* If there is no decimal point, start usecs after the '\0'. */ if (!usecs) usecs = ++scan; /* Add zeros until usecs has six digits. */ while (scan < usecs + 6) *scan++ = '0'; /* Accept no more than six digits. */ usecs[6] = '\0'; period = (long long) atoi (secs) * USECSPERSEC + atoi (usecs); argc--, argv++; } else if ((strcmp_abbrev (argv[0], "-worm") == 0)) { int length; int *x, *y; int i; if (argc <= 1) give_usage (); length = atoi (argv[1]); if (length <= 0) give_usage (); else length++; /* No o-b-o-e playing here! */ /* The pointer-to-worm serves as a flag var, since it was initialized to NULL above. */ worm = (struct worm *) malloc ( sizeof (struct worm)); if (worm == NULL) { perror (progname); exit (1); } /* Init to impossible values so draw_circles() knows whether worm has been seen before. */ x = (int *) malloc (length * sizeof (int)); y = (int *) malloc (length * sizeof (int)); if (!x || !y) { perror (progname); exit (1); } worm->length = length; worm->center_x = x; worm->center_y = y; worm->radius = -1; worm->sol = -1; worm->au = -1; worm->direction = -1; /* Init to impossible values so draw_circles() knows whether worm has been seen before. */ for (i = 0; i < length; i++) { worm->center_x[i] = -1; worm->center_y[i] = -1; } /* Push our arglist along. */ argv++, argc--; /* draw_circles() will handle worm from here. */ } else { give_usage (); break; } } else { /* unrecognized option */ give_usage (); } } /* Try to grok the ascii_phase specification. */ { phase = get_date (ascii_phase, NULL); if (phase == -1) { fprintf (stderr, "%s: can't parse `%s' as a time\n", progname, ascii_phase); exit (1); } /* Find the smallest equivalent value for phase. */ phase = (phase * USECSPERSEC) % period; } disp_name || (disp_name = getenv ("DISPLAY")); disp = XOpenDisplay (disp_name); if (! disp) { fprintf (stderr, "%s: Can't open display %s\n", progname, disp_name); exit (1); } screen = DefaultScreen (disp); root = RootWindow (disp, screen); /* Try to allocate a color cell for the changing color. */ default_cmap = DefaultColormap (disp, screen); if (! XAllocColorCells (disp, default_cmap, False, NULL, 0, &circle_pixel, 1)) { fprintf (stderr, "%s: In order to run, the display %s must have " "a read/write color cell available.\n", progname, disp_name); exit (2); } { XGCValues v; v.foreground = circle_pixel; v.line_width = INTERIOR_WIDTH; circle_gc = XCreateGC (disp, root, GCLineWidth | GCForeground, &v); v.foreground = BlackPixel (disp, screen); v.line_width = BORDER_WIDTH; border_gc = XCreateGC (disp, root, GCLineWidth | GCForeground, &v); if (worm) { /* The worm's foreground is black, and its "background" is the same color as the circles, so when we repaint it somewhere else, drawing over the old one with back_gc works. */ v.foreground = BlackPixel (disp, screen); v.line_width = INTERIOR_WIDTH - 4; worm->fore_gc = XCreateGC (disp, root, GCLineWidth | GCForeground, &v); v.foreground = circle_pixel; v.line_width = INTERIOR_WIDTH - 4; worm->back_gc = XCreateGC (disp, root, GCLineWidth | GCForeground, &v); } } { fd_set inputfds; struct timeval next_tick; tick (&next_tick); draw_circles (worm, NOT_FROM_EXPOSURE); XSelectInput (disp, root, ExposureMask); for (;;) { int has_event; XFlush (disp); FD_ZERO (&inputfds); FD_SET (ConnectionNumber (disp), &inputfds); if ((has_event = select (32, &inputfds, NULL, NULL, &next_tick)) == -1) { perror (progname); exit (2); } if (has_event) { XEvent event; XNextEvent (disp, &event); switch (event.type) { case Expose: /* Remove any other queued expose events; one draw_circles call will take care of them all. */ while (XCheckMaskEvent (disp, ExposureMask, &event)) ; draw_circles (worm, FROM_EXPOSURE); break; case MappingNotify: break; default: fprintf (stderr, "%s: Unexpected event type: %d\n", progname, event.type); exit (2); } } tick (&next_tick); if (worm) { move_worm (worm); draw_worm (worm, NOT_FROM_EXPOSURE); } } } XCloseDisplay (disp); exit (0); } #define CENTER_RADIUS(cx, cy, r) (cx) - (r), (cy)-(r), 2*(r), 2*(r) void draw_circles (struct worm *worm, int from_exposure_p) { int width = DisplayWidth (disp, screen); int height = DisplayHeight (disp, screen); int center_x = width / 2; int center_y = height / 2; int radius = ((width < height) ? width : height) / 6; int spacing = radius / .86602540378443864690; /* cos (30) */ int center_x_1 = center_x + spacing * .96592582628906828678; /* cos (15) */ int center_y_1 = center_y - spacing * .25881904510252076221; /* sin (15) */ int center_x_2 = center_x + spacing * -.70710678118654752351; /* cos (135) */ int center_y_2 = center_y - spacing * .70710678118654752528; /* sin (135) */ int center_x_3 = center_x + spacing * -.25881904510252076462; /* cos (255) */ int center_y_3 = center_y - spacing * -.96592582628906828615; /* sin (255) */ XDrawArc (disp, root, border_gc, CENTER_RADIUS (center_x_1, center_y_1, radius), 0 * 64, 360 * 64); XDrawArc (disp, root, border_gc, CENTER_RADIUS (center_x_2, center_y_2, radius), 0 * 64, 360 * 64); XDrawArc (disp, root, border_gc, CENTER_RADIUS (center_x_3, center_y_3, radius), 0 * 64, 360 * 64); XDrawArc (disp, root, circle_gc, CENTER_RADIUS (center_x_1, center_y_1, radius), 0 * 64, 360 * 64); XDrawArc (disp, root, circle_gc, CENTER_RADIUS (center_x_2, center_y_2, radius), 0 * 64, 360 * 64); XDrawArc (disp, root, circle_gc, CENTER_RADIUS (center_x_3, center_y_3, radius), 0 * 64, 360 * 64); /* Maybe set up the worm. */ if (worm) { int which; SRANDOM (time (NULL)); which = RANDOM () % NUM_CIRCLES; worm->sol_x[0] = center_x_1; worm->sol_y[0] = center_y_1; worm->sol_x[1] = center_x_2; worm->sol_y[1] = center_y_2; worm->sol_x[2] = center_x_3; worm->sol_y[2] = center_y_3; /* Around whom orbit we? (One of above three.) */ if (worm->sol == -1) worm->sol = which; if (worm->au == -1) worm->au = radius; if (worm->direction == -1) worm->direction = RANDOM () % 2; /* Calculate some point on a circle, given radius and center. */ if ((worm->center_x[0] == -1) || (worm->center_y[0] == -1)) place_worm (worm); /* sets worm's center */ if (worm->radius == -1) worm->radius = INTERIOR_WIDTH - 8; /* Finally, put it on the screen. */ draw_worm (worm, from_exposure_p); } } /* Initial placement of the worm. Movement after this is done by * incrementing or decrementing worm->center_x and adjusting * worm->center_y accordingly, or vice_versa. */ void place_worm (struct worm *worm) { /* Be only somewhat random about this. */ int compass_pt, i; compass_pt = RANDOM () % 4; /* The compass points around the circle with center C are: * * 1 * * 4 C 2 * * 3 */ switch (compass_pt) { case 0: worm->center_x[0] = worm->sol_x[worm->sol]; worm->center_y[0] = worm->sol_y[worm->sol] + worm->au; break; case 1: worm->center_x[0] = worm->sol_x[worm->sol] + worm->au; worm->center_y[0] = worm->sol_y[worm->sol]; break; case 2: worm->center_x[0] = worm->sol_x[worm->sol]; worm->center_y[0] = worm->sol_y[worm->sol] - worm->au; break; case 3: default: /* `default' is impossible, but what the heck */ worm->center_x[0] = worm->sol_x[worm->sol] - worm->au; worm->center_y[0] = worm->sol_y[worm->sol]; break; } for (i = 1; i < worm->length; i++) { /* Init the rest of the array to point off-screen, so we don't erase random patches of display before the worm has reached its full length. */ worm->center_x[i] = -1; worm->center_y[i] = -1; } worm->last_sol = worm->sol; } void move_worm (struct worm *worm) { static int jumped = 0; static int maybe = 1; int idx_old, idx_new, sol, au; /* This is for knowing when not to jump; it is functionally * unrelated to worm->last_sol. It preserves the same information, * but longer. */ static int last_sol; /* Quadrant boundaries around a circle with center C are: * * 1 * * 4 C 2 * * 3 * * Source is inclusive and destination is non-inclusive; thus, * quadrant 1-2 includes point 1, but not 2. The order in which the * boundary numbers are given indicates whether direction is * clockwise or counter-clockwise; however I think the direction is * not usually relevant. * * Quadrant 1-2 / 2-1: worm(x) >= C(x) && worm(y) > C(y): * increment x to move clockwise * decrement x to move counterclockwise * * Quadrant 2-3 / 3-2: worm(x) > C(x) && worm(y) <= C(y): * decrement y to move clockwise * increment y to move counterclockwise * * Quadrant 3-4 / 4-3: worm(x) <= C(x) && worm(y) < C(y): * decrement x to move clockwise * increment x to move counterclockwise * * Quadrant 4-1 / 4-1: worm(x) < C(x) && worm(y) >= C(y): * increment y to move clockwise * decrement y to move counterclockwise */ /* First save the old coordinates, for repaint. */ idx_old = worm->idx; idx_new = (idx_old == (worm->length - 1)) ? 0 : (idx_old + 1); /* Advance our worm's segment pointer. */ worm->idx = idx_new; /* Copy the previous segment's information into this segment, since worms must slither nondisjointly. */ worm->center_x[idx_new] = worm->center_x[idx_old]; worm->center_y[idx_new] = worm->center_y[idx_old]; /* Record whom we're orbiting. */ worm->last_sol = worm->sol; /* For brevity's sake. */ sol = worm->sol; au = worm->au; /* 1. find out which quadrant we're in * 2. do the operation indicated by worm->direction (see table above) * 3. then adjust the other coordinate accordingly */ if ( (worm->center_x[idx_new] >= worm->sol_x[sol]) /* 1-2 */ && (worm->center_y[idx_new] < worm->sol_y[sol])) { if (worm->direction == CLOCKWISE) { worm->center_x[idx_new]++; worm->center_y[idx_new] = worm->sol_y[sol] - sqrt (abs (SQUARE (au) - SQUARE (abs (worm->center_x[idx_new] - worm->sol_x[sol])))); } else if (worm->direction == COUNTERCLOCKWISE) { worm->center_x[idx_new]--; worm->center_y[idx_new] = worm->sol_y[sol] - sqrt (abs (SQUARE (au) - SQUARE (abs (worm->center_x[idx_new] - worm->sol_x[sol])))); } } else if ( (worm->center_x[idx_new] > worm->sol_x[sol]) /* 2-3 */ && (worm->center_y[idx_new] >= worm->sol_y[sol])) { if (worm->direction == CLOCKWISE) { worm->center_y[idx_new]++; worm->center_x[idx_new] = worm->sol_x[sol] + sqrt (abs (SQUARE (au) - SQUARE (abs (worm->center_y[idx_new] - worm->sol_y[sol])))); } else if (worm->direction == COUNTERCLOCKWISE) { worm->center_y[idx_new]--; worm->center_x[idx_new] = worm->sol_x[sol] + sqrt (abs (SQUARE (au) - SQUARE (abs (worm->center_y[idx_new] - worm->sol_y[sol])))); } } else if ( (worm->center_x[idx_new] <= worm->sol_x[sol]) /* 3-4 */ && (worm->center_y[idx_new] > worm->sol_y[sol])) { if (worm->direction == CLOCKWISE) { worm->center_x[idx_new]--; worm->center_y[idx_new] = worm->sol_y[sol] + sqrt (abs (SQUARE (au) - SQUARE (abs (worm->center_x[idx_new] - worm->sol_x[sol])))); } else if (worm->direction == COUNTERCLOCKWISE) { worm->center_x[idx_new]++; worm->center_y[idx_new] = worm->sol_y[sol] + sqrt (abs (SQUARE (au) - SQUARE (abs (worm->center_x[idx_new] - worm->sol_x[sol])))); } } else if ( (worm->center_x[idx_new] < worm->sol_x[sol]) /* 4-1 */ && (worm->center_y[idx_new] <= worm->sol_y[sol])) { if (worm->direction == CLOCKWISE) { worm->center_y[idx_new]--; worm->center_x[idx_new] = worm->sol_x[sol] - sqrt (abs (SQUARE (au) - SQUARE (abs (worm->center_y[idx_new] - worm->sol_y[sol])))); } else if (worm->direction == COUNTERCLOCKWISE) { worm->center_y[idx_new]++; worm->center_x[idx_new] = worm->sol_x[sol] - sqrt (abs (SQUARE (au) - SQUARE (abs (worm->center_y[idx_new] - worm->sol_y[sol])))); } } else { fprintf (stderr, "%s: impossible situation\n", progname); exit (1); } /* Check if we've come to a fork in the road, take it if so. */ { int i; int x, y; int dist; /* Have we recently jumped (i.e., are we still in the "jumpy" region)? */ if (jumped) { x = abs (worm->center_x[idx_new] - worm->sol_x[last_sol]); y = abs (worm->center_y[idx_new] - worm->sol_y[last_sol]); dist = (int) sqrt (SQUARE (x) + SQUARE (y)); if (dist > au) { /* Once we're far enough along on the current circle, we * can reset jump, but until we do that, we can't jump at * all. This insures that we only attempt one jump as we * pass through one of the "jumpy" regions. */ jumped = 0; last_sol = sol; /* Will we jump next time? We only want to jump at half * the forks we come to, so the worm has a chance to * slither in every direction on every circle. */ maybe = RANDOM () % JUMP_PROB; } } else /* !jumped */ { /* Save sol for next time we jump. */ last_sol = sol; for (i = 0; i < NUM_CIRCLES; i++) { /* No need to consider the current orbit. */ if (i == sol) continue; x = abs (worm->center_x[idx_new] - worm->sol_x[i]); y = abs (worm->center_y[idx_new] - worm->sol_y[i]); dist = (int) sqrt (SQUARE (x) + SQUARE (y)); if (dist <= au) { if (maybe) { /* Hop over to the next circle. */ jumped = 1; worm->sol = i; worm->direction = ! (worm->direction); } else /* !maybe */ { jumped = 1; last_sol = i; } } } } } } void draw_worm (struct worm *worm, int from_exposure_p) { if (from_exposure_p) /* Redraw the whole body -- all segments. */ { int i, len; len = worm->length; for (i = 0; i < len; i++) XDrawArc (disp, root, worm->fore_gc, CENTER_RADIUS (worm->center_x[i], worm->center_y[i], worm->radius), 0 * 64, 360 * 64); /* Call again, only to re-erase the ghost of the last segment. */ draw_worm (worm, NOT_FROM_EXPOSURE); } else /* Just erase least recent segment and draw next segment. */ { int tail, idx; idx = worm->idx; tail = (idx == (worm->length - 1)) ? 0 : (idx + 1); XDrawArc (disp, root, worm->back_gc, CENTER_RADIUS (worm->center_x[tail], worm->center_y[tail], worm->radius), 0 * 64, 360 * 64); XDrawArc (disp, root, worm->fore_gc, CENTER_RADIUS (worm->center_x[idx], worm->center_y[idx], worm->radius), 0 * 64, 360 * 64); } } void give_usage () { char *usage = "\ Usage: %s [-display ] [-period ] [-phase