xss/magic.c

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/* magic -- "Magic" (qix) screen saver hack
* Copyright (C) 2008 Neale Pickett <neale@woozle.org>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <time.h>
#include <X11/Xlib.h>
#include "obj.h"
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#define FPS 17 /* Frames Per Second */
#define TRAILPCT 50 /* Percentage of width to cover */
#define MAXDELTAPML 14 /* Maximum velocity per-mil width */
#define MINDELTAPML 2 /* Minimum verocity per-mil width */
#define MINCOLORDELTA 40 /* Minimum color steps per line */
#define MAXCOLORDELTA 150 /* Maximum color steps per line */
#define nsec (1000000000 / FPS)
#define max(a,b) (((a) > (b)) ? (a) : (b))
#define randint(x) (random() % (x))
#define rand(l, h) (randint(h-l) + l)
#define sum(a, b, v, m) \
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if (b < -v) { \
v *= -1; \
a = v - b; \
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} else if (m - b <= v) { \
v *= -1; \
a = v + b; \
} else { \
a = v + b; \
}
int
main(int argc, char * const argv[])
{
Display *display;
Window w = (Window)0;
GC egc = (GC)0;
XSegment *lines = NULL;
char *winstr = NULL;
int i;
for (i = 1; i < argc; i += 1) {
if (0 == strcmp(argv[i], "-window-id")) {
/* For compatibility with xscreensaver. We just ignore it. */
} else if (winstr) {
w = (Window)-1;
break;
} else {
winstr = argv[i];
}
}
if (! winstr) winstr = getenv("XSS_WINDOW");
if (winstr) {
char *end;
if (winstr[0] == '0' && winstr[1] == 'x') {
w = (Window)strtol(winstr + 2, &end, 16);
} else {
w = (Window)strtol(winstr, &end, 10);
}
if ('\0' != *end) {
w = (Window)-1;
}
}
if ((Window)-1 == w) {
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(void)fprintf(stderr, "Usage: %s [WINDOW_ID]\n", argv[0]);
return 64; /* EX_USAGE */
}
if (! (display = XOpenDisplay(NULL))) {
(void)fprintf(stderr, "cannot open display");
return 69; /* EX_UNAVAILABLE */
}
try {
int screen = DefaultScreen(display);
Window root = RootWindow(display, screen);
Colormap cmap = DefaultColormap(display, screen);
XSegment velocity;
int width, height, nlines;
unsigned short red, green, blue; /* because color.red is reset to the color you got */
int dred, dgreen, dblue;
GC gc;
XColor color;
if (w) {
XWindowAttributes wa;
XGetWindowAttributes(display, w, &wa);
width = wa.width;
height = wa.height;
} else {
XSetWindowAttributes wa;
zero(wa);
wa.override_redirect = 1;
wa.background_pixel = BlackPixel(display, screen);
width = DisplayWidth(display, screen) / 3;
height = DisplayHeight(display, screen) / 3;
w = XCreateWindow(display, root,
0, 0,
width, height, 0,
CopyFromParent, CopyFromParent, CopyFromParent,
CWBackPixel,
&wa);
XMapWindow(display, w);
}
srandom((unsigned int)time(NULL));
{
int u, l;
u = width * MAXDELTAPML / 1000;
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l = max(width * MINDELTAPML / 1000, 1);
velocity.x1 = (short)rand(l, u);
velocity.y1 = (short)rand(l, u);
velocity.x2 = (short)rand(l, u);
velocity.y2 = (short)rand(l, u);
}
nlines = (width * TRAILPCT) / (max(velocity.y1, velocity.y2) * 100);
lines = (XSegment *)calloc(nlines, sizeof(XSegment));
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lines[0].x1 = (short)randint(width);
lines[0].y1 = (short)randint(height);
lines[0].x2 = (short)randint(width);
lines[0].y2 = (short)randint(height);
/* Allocate graphics contexts */
{
XGCValues values;
values.background = values.foreground = BlackPixel(display, screen);
egc = XCreateGC(display, w, GCBackground | GCForeground, &values);
red = color.red = (unsigned short)randint(65536);
green = color.green = (unsigned short)randint(65536);
blue = color.blue = (unsigned short)randint(65536);
dred = rand(MINCOLORDELTA, MAXCOLORDELTA);
dgreen = rand(MINCOLORDELTA, MAXCOLORDELTA);
dblue = rand(MINCOLORDELTA, MAXCOLORDELTA);
if (! XAllocColor(display, cmap, &color)) break;
values.foreground = color.pixel;
gc = XCreateGC(display, w, GCBackground | GCForeground, &values);
}
for (i = 0; ;) {
XSegment segments[2];
struct timespec req = {0, nsec};
int j = (i + 1) % nlines;
/* Erase old line */
(void)memcpy(segments + 0, lines + j, sizeof(XSegment));
(void)memcpy(segments + 1, lines + j, sizeof(XSegment));
segments[1].x1 = width - segments[0].x1;
segments[1].x2 = width - segments[0].x2;
(void)XDrawSegments(display, (Drawable)w, egc, segments, 2);
/* Calculate new line */
sum(lines[j].x1, lines[i].x1, velocity.x1, width);
sum(lines[j].y1, lines[i].y1, velocity.y1, height);
sum(lines[j].x2, lines[i].x2, velocity.x2, width);
sum(lines[j].y2, lines[i].y2, velocity.y2, height);
/* Draw new line */
(void)memcpy(segments + 0, lines + j, sizeof(XSegment));
(void)memcpy(segments + 1, lines + j, sizeof(XSegment));
segments[1].x1 = width - segments[0].x1;
segments[1].x2 = width - segments[0].x2;
(void)XDrawSegments(display, (Drawable)w, gc, segments, 2);
/* Change color */
{
unsigned long pixel = color.pixel;
sum(color.red = red, red, dred, 65536);
sum(color.green = green, green, dgreen, 65536);
sum(color.blue = blue, blue, dblue, 65536);
if (! XAllocColor(display, cmap, &color)) break;
if (! XSetForeground(display, gc, color.pixel)) break;
if (! XFreeColors(display, cmap, &pixel, 1, 0)) break;
}
XSync(display, True);
(void)nanosleep(&req, NULL);
i = j;
}
(void)XFreeGC(display, gc);
}
if (lines) {
free(lines);
}
if (display) {
if (egc) {
(void)XFreeGC(display, egc);
}
(void)XCloseDisplay(display);
}
except {
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(void)fprintf(stderr, "Error: %s\n", exception);
return 69; /* EX_UNAVAILABLE */
}
return 0;
}