scripts/C/xaspect.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include <math.h>
   5 #include <inttypes.h>
   6 #include <xcb/xcb.h>
   7
   8 #define MKASPECT(w, h) { (double)w/h, #w ":" #h }
   9
  10 /* Table of common monitor aspect ratios.  Add to this as necessary. */
  11 static struct aspect {
  12         double ratio;
  13         char *name;
  14 } aspects[] = {
  15         MKASPECT(16, 10),
  16         MKASPECT(16, 9),
  17         MKASPECT(8, 3),
  18         MKASPECT(5, 4),
  19         MKASPECT(4, 3)
  20 };
  21
  22 /*
  23  * Get the xcb screen structure for the specified screen, or NULL if it doesn't
  24  * exist.
  25  */
  26 static xcb_screen_t *getscreen(xcb_connection_t *c, int screen)
  27 {
  28         xcb_screen_iterator_t iter;
  29
  30         iter = xcb_setup_roots_iterator(xcb_get_setup(c));
  31         while (iter.rem) {
  32                 if (screen == 0)
  33                         return iter.data;
  34                 screen--;
  35                 xcb_screen_next(&iter);
  36         }
  37
  38         return NULL;
  39 }
  40
  41 char *testaspect(xcb_screen_t *screen)
  42 {
  43         unsigned int w = screen->width_in_millimeters;
  44         unsigned int h = screen->height_in_millimeters;
  45
  46         double ratio = (double)w/h;
  47         double diff = 0;
  48         char *best = NULL;
  49         int i;
  50
  51         for (i = 0; i < (sizeof aspects / sizeof aspects[0]); i++) {
  52                 if (!best || fabs(aspects[i].ratio - ratio) < diff) {
  53                         best = aspects[i].name;
  54                         diff = fabs(aspects[i].ratio - ratio);
  55                 }
  56         }
  57
  58         return best;
  59 }
  60
  61 struct options {
  62         char *displayname;
  63         int showdimensions;
  64 } *parseoptions(int argc, char **argv)
  65 {
  66         static struct options opts = { 0 };
  67         int i;
  68
  69         for (i = 1; i < argc; i++) {
  70                 if (strcmp(argv[i], "-display") == 0) {
  71                         if (++i < argc) {
  72                                 opts.displayname = argv[i];
  73                                 continue;
  74                         }
  75                         fprintf(stderr, "-display requires an argument\n");
  76                 } else if (strcmp(argv[i], "-dimensions") == 0) {
  77                         opts.showdimensions = 1;
  78                 }
  79         }
  80
  81         return &opts;
  82 }
  83
  84 int main(int argc, char **argv)
  85 {
  86         xcb_connection_t *display;
  87         xcb_screen_t     *screen;
  88         int screen_num;
  89
  90         struct options *opts = parseoptions(argc, argv);
  91
  92         display = xcb_connect(opts->displayname, &screen_num);
  93         if (xcb_connection_has_error(display)) {
  94                 fprintf(stderr, "Failed to open display.\n");
  95                 xcb_disconnect(display);
  96                 return EXIT_FAILURE;
  97         }
  98
  99         screen = getscreen(display, screen_num);
 100         if (!screen) {
 101                 fprintf(stderr, "Invalid screen number.\n");
 102                 xcb_disconnect(display);
 103                 return EXIT_FAILURE;
 104         }
 105
 106         if (opts->showdimensions) {
 107                 printf("%" PRIu16 "x%" PRIu16 "-",
 108                        screen->width_in_pixels, screen->height_in_pixels);
 109         }
 110         printf("%s\n", testaspect(screen));
 111
 112         xcb_disconnect(display);
 113         return EXIT_SUCCESS;
 114 }