* vim:ts=4:sw=4:expandtab
*
* i3 - an improved dynamic tiling window manager
- * © 2009-2014 Michael Stapelberg and contributors (see also: LICENSE)
+ * © 2009 Michael Stapelberg and contributors (see also: LICENSE)
*
*/
#include "libi3.h"
+
#include <math.h>
+#include <stdlib.h>
+#include <xcb/xcb_xrm.h>
+
+static long dpi;
+
+static long init_dpi_fallback(void) {
+ return (double)root_screen->height_in_pixels * 25.4 / (double)root_screen->height_in_millimeters;
+}
+
+/*
+ * Initialize the DPI setting.
+ * This will use the 'Xft.dpi' X resource if available and fall back to
+ * guessing the correct value otherwise.
+ */
+void init_dpi(void) {
+ xcb_xrm_database_t *database = NULL;
+ char *resource = NULL;
+
+ if (conn == NULL) {
+ goto init_dpi_end;
+ }
+
+ database = xcb_xrm_database_from_default(conn);
+ if (database == NULL) {
+ ELOG("Failed to open the resource database.\n");
+ goto init_dpi_end;
+ }
+
+ xcb_xrm_resource_get_string(database, "Xft.dpi", NULL, &resource);
+ if (resource == NULL) {
+ DLOG("Resource Xft.dpi not specified, skipping.\n");
+ goto init_dpi_end;
+ }
+
+ char *endptr;
+ double in_dpi = strtod(resource, &endptr);
+ if (in_dpi == HUGE_VAL || dpi < 0 || *endptr != '\0' || endptr == resource) {
+ ELOG("Xft.dpi = %s is an invalid number and couldn't be parsed.\n", resource);
+ dpi = 0;
+ goto init_dpi_end;
+ }
+ dpi = lround(in_dpi);
-extern xcb_screen_t *root_screen;
+ DLOG("Found Xft.dpi = %ld.\n", dpi);
+
+init_dpi_end:
+ free(resource);
+
+ if (database != NULL) {
+ xcb_xrm_database_free(database);
+ }
+
+ if (dpi == 0) {
+ DLOG("Using fallback for calculating DPI.\n");
+ dpi = init_dpi_fallback();
+ DLOG("Using dpi = %ld\n", dpi);
+ }
+}
+
+/*
+ * This function returns the value of the DPI setting.
+ *
+ */
+long get_dpi_value(void) {
+ return dpi;
+}
/*
* Convert a logical amount of pixels (e.g. 2 pixels on a “standard” 96 DPI
*
*/
int logical_px(const int logical) {
- const int dpi = (double)root_screen->height_in_pixels * 25.4 /
- (double)root_screen->height_in_millimeters;
+ if (root_screen == NULL) {
+ /* Dpi info may not be available when parsing a config without an X
+ * server, such as for config file validation. */
+ return logical;
+ }
+
/* There are many misconfigurations out there, i.e. systems with screens
* whose dpi is in fact higher than 96 dpi, but not significantly higher,
* so software was never adapted. We could tell people to reconfigure their