scripts/C/xaspect.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include <math.h>
   5 #include <xcb/xcb.h>
   6
   7 #define MKASPECT(w, h) { (double)w/h, #w ":" #h }
   8
   9 /* Table of common monitor aspect ratios.  Add to this as necessary. */
  10 static struct aspect {
  11         double ratio;
  12         char *name;
  13 } aspects[] = {
  14         MKASPECT(16, 10),
  15         MKASPECT(16, 9),
  16         MKASPECT(8, 3),
  17         MKASPECT(5, 4),
  18         MKASPECT(4, 3)
  19 };
  20
  21 /*
  22  * Get the xcb screen structure for the specified screen, or NULL if it doesn't
  23  * exist.
  24  */
  25 static xcb_screen_t *getscreen(xcb_connection_t *c, int screen)
  26 {
  27         xcb_screen_iterator_t iter;
  28
  29         iter = xcb_setup_roots_iterator(xcb_get_setup(c));
  30         while (iter.rem) {
  31                 if (screen == 0)
  32                         return iter.data;
  33                 screen--;
  34                 xcb_screen_next(&iter);
  35         }
  36
  37         return NULL;
  38 }
  39
  40 char *testaspect(xcb_screen_t *screen)
  41 {
  42         unsigned int w = screen->width_in_millimeters;
  43         unsigned int h = screen->height_in_millimeters;
  44
  45         double ratio = (double)w/h;
  46         double diff = 0;
  47         char *best = NULL;
  48         int i;
  49
  50         for (i = 0; i < (sizeof aspects / sizeof aspects[0]); i++) {
  51                 if (!best || fabs(aspects[i].ratio - ratio) < diff) {
  52                         best = aspects[i].name;
  53                         diff = fabs(aspects[i].ratio - ratio);
  54                 }
  55         }
  56
  57         return best;
  58 }
  59
  60 int main(int argc, char **argv)
  61 {
  62         xcb_connection_t *display;
  63         xcb_screen_t     *screen;
  64         char *dpynam = NULL;
  65         int screen_num;
  66
  67         if (argc > 2 && strcmp(argv[1], "-display") == 0)
  68                 dpynam = argv[2];
  69
  70         display = xcb_connect(dpynam, &screen_num);
  71         if (xcb_connection_has_error(display)) {
  72                 fprintf(stderr, "Failed to open display.\n");
  73                 xcb_disconnect(display);
  74                 return EXIT_FAILURE;
  75         }
  76
  77         screen = getscreen(display, screen_num);
  78         if (!screen) {
  79                 fprintf(stderr, "Invalid screen number.\n");
  80                 xcb_disconnect(display);
  81                 return EXIT_FAILURE;
  82         }
  83
  84         printf("%s\n", testaspect(screen));
  85
  86         xcb_disconnect(display);
  87         return EXIT_SUCCESS;
  88 }