Add xrdb and dpi query

1 files changed, 18 insertions, 3 deletions

diff --git a/x11.c b/x11.c
index 1cf4393..f95d4f5 100644
--- a/x11.c
+++ b/x11.c
@@ -1,4 +1,5 @@
 #include <stdbool.h>
+#include <assert.h>
 #include <glib.h>
 #include <math.h>
 #include <cairo.h>
@@ -14,10 +15,12 @@
 struct Window {
     xcb_screen_t *screen;
     xcb_connection_t *connection;
+	xcb_xrm_database_t *database;
     xcb_drawable_t window;
     xcb_visualtype_t *visual_type;
     cairo_surface_t *surface;
     cairo_t *cr;
+	double dpi;
 };
 
 Window *window_create(void)
@@ -26,6 +29,19 @@ Window *window_create(void)
 
     int preferred_screen = 0;
     win->connection = xcb_connect(NULL, &preferred_screen);
+	assert(win->connection != NULL && !xcb_connection_has_error(win->connection));
+
+	win->database = xcb_xrm_database_from_default(win->connection);
+	assert(win->database != NULL);
+
+	char *dpi_value;
+	if (xcb_xrm_resource_get_string(win->database, "Xft.dpi", "Xft.dpi", &dpi_value) >= 0) {
+		win->dpi = strtod(dpi_value, NULL);
+		g_free(dpi_value);
+	} else {
+		// TODO: Calculate automatically somehow
+		win->dpi = 96.0;
+	}
 
     xcb_screen_iterator_t iter = xcb_setup_roots_iterator(xcb_get_setup(win->connection));
 
@@ -35,7 +51,6 @@ Window *window_create(void)
     }
 
     win->screen = iter.data;
-
     win->window = xcb_generate_id(win->connection);
 
     int y = 0, x = 0, h = 300, w = 400;
@@ -84,8 +99,7 @@ cairo_t *window_get_context(Window *win)
 
 double window_get_scale(Window *win)
 {
-    // TODO
-    return 1;
+	return MAX(1, win->dpi/96.);
 }
 
 void window_paint_surface(Window *win, cairo_surface_t *surface, int width, int height)
@@ -107,6 +121,7 @@ void window_destroy(Window *win)
 {
     cairo_destroy(win->cr);
     cairo_surface_destroy(win->surface);
+	xcb_xrm_database_free(win->database);
     xcb_disconnect(win->connection);
     g_free(win);
 }