scripts/C/xaspect.c

   1 /*
   2  * Copyright © 2007 Nick Bowler
   3  *
   4  * License WTFPL2: Do What The Fuck You Want To Public License, version 2.
   5  * This is free software: you are free to do what the fuck you want to.
   6  * There is NO WARRANTY, to the extent permitted by law.
   7  */
   8
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <math.h>
  13 #include <inttypes.h>
  14 #include <xcb/xcb.h>
  15
  16 #define MKASPECT(w, h) { (double)w/h, #w ":" #h }
  17
  18 /* Table of common monitor aspect ratios.  Add to this as necessary. */
  19 static struct aspect {
  20         double ratio;
  21         char *name;
  22 } aspects[] = {
  23         MKASPECT(16, 10),
  24         MKASPECT(16, 9),
  25         MKASPECT(8, 3),
  26         MKASPECT(5, 4),
  27         MKASPECT(4, 3)
  28 };
  29
  30 /*
  31  * Get the xcb screen structure for the specified screen, or NULL if it doesn't
  32  * exist.
  33  */
  34 static xcb_screen_t *getscreen(xcb_connection_t *c, int screen)
  35 {
  36         xcb_screen_iterator_t iter;
  37
  38         iter = xcb_setup_roots_iterator(xcb_get_setup(c));
  39         while (iter.rem) {
  40                 if (screen == 0)
  41                         return iter.data;
  42                 screen--;
  43                 xcb_screen_next(&iter);
  44         }
  45
  46         return NULL;
  47 }
  48
  49 char *testaspect(xcb_screen_t *screen)
  50 {
  51         unsigned int w = screen->width_in_millimeters;
  52         unsigned int h = screen->height_in_millimeters;
  53
  54         double ratio = (double)w/h;
  55         double diff = 0;
  56         char *best = NULL;
  57         int i;
  58
  59         for (i = 0; i < (sizeof aspects / sizeof aspects[0]); i++) {
  60                 if (!best || fabs(aspects[i].ratio - ratio) < diff) {
  61                         best = aspects[i].name;
  62                         diff = fabs(aspects[i].ratio - ratio);
  63                 }
  64         }
  65
  66         return best;
  67 }
  68
  69 struct options {
  70         char *displayname;
  71         int showdimensions;
  72 } *parseoptions(int argc, char **argv)
  73 {
  74         static struct options opts = { 0 };
  75         int i;
  76
  77         for (i = 1; i < argc; i++) {
  78                 if (strcmp(argv[i], "-display") == 0) {
  79                         if (++i < argc) {
  80                                 opts.displayname = argv[i];
  81                                 continue;
  82                         }
  83                         fprintf(stderr, "-display requires an argument\n");
  84                 } else if (strcmp(argv[i], "-dimensions") == 0) {
  85                         opts.showdimensions = 1;
  86                 }
  87         }
  88
  89         return &opts;
  90 }
  91
  92 int main(int argc, char **argv)
  93 {
  94         xcb_connection_t *display;
  95         xcb_screen_t     *screen;
  96         int screen_num;
  97
  98         struct options *opts = parseoptions(argc, argv);
  99
 100         display = xcb_connect(opts->displayname, &screen_num);
 101         if (xcb_connection_has_error(display)) {
 102                 fprintf(stderr, "Failed to open display.\n");
 103                 xcb_disconnect(display);
 104                 return EXIT_FAILURE;
 105         }
 106
 107         screen = getscreen(display, screen_num);
 108         if (!screen) {
 109                 fprintf(stderr, "Invalid screen number.\n");
 110                 xcb_disconnect(display);
 111                 return EXIT_FAILURE;
 112         }
 113
 114         if (opts->showdimensions) {
 115                 printf("%" PRIu16 "x%" PRIu16 "-",
 116                        screen->width_in_pixels, screen->height_in_pixels);
 117         }
 118         printf("%s\n", testaspect(screen));
 119
 120         xcb_disconnect(display);
 121         return EXIT_SUCCESS;
 122 }