Add libi3/load_font, use it everywhere

…except for i3bar, which needs slightly more information about the font

libi3/load_font.c

@@ -0,0 +1,74 @@
+/*
+ * vim:ts=4:sw=4:expandtab
+ *
+ * i3 - an improved dynamic tiling window manager
+ *
+ * © 2009-2011 Michael Stapelberg and contributors
+ *
+ * See file LICENSE for license information.
+ *
+ */
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <err.h>
+
+#include "libi3.h"
+
+extern xcb_connection_t *conn;
+
+/*
+ * Loads a font for usage, also getting its height. If fallback is true,
+ * the fonts 'fixed' or '-misc-*' will be loaded instead of exiting.
+ *
+ */
+i3Font load_font(const char *pattern, bool fallback) {
+    i3Font font;
+    xcb_void_cookie_t font_cookie;
+    xcb_list_fonts_with_info_cookie_t info_cookie;
+    xcb_list_fonts_with_info_reply_t *info_reply;
+    xcb_generic_error_t *error;
+
+    /* Send all our requests first */
+    font.id = xcb_generate_id(conn);
+    font_cookie = xcb_open_font_checked(conn, font.id, strlen(pattern), pattern);
+    info_cookie = xcb_list_fonts_with_info(conn, 1, strlen(pattern), pattern);
+
+    /* Check for errors. If errors, fall back to default font. */
+    error = xcb_request_check(conn, font_cookie);
+
+    /* If we fail to open font, fall back to 'fixed' */
+    if (fallback && error != NULL) {
+        ELOG("Could not open font %s (X error %d). Trying fallback to 'fixed'.\n",
+             pattern, error->error_code);
+        pattern = "fixed";
+        font_cookie = xcb_open_font_checked(conn, font.id, strlen(pattern), pattern);
+        info_cookie = xcb_list_fonts_with_info(conn, 1, strlen(pattern), pattern);
+
+        /* Check if we managed to open 'fixed' */
+        error = xcb_request_check(conn, font_cookie);
+
+        /* Fall back to '-misc-*' if opening 'fixed' fails. */
+        if (error != NULL) {
+            ELOG("Could not open fallback font 'fixed', trying with '-misc-*'.\n");
+            pattern = "-misc-*";
+            font_cookie = xcb_open_font_checked(conn, font.id, strlen(pattern), pattern);
+            info_cookie = xcb_list_fonts_with_info(conn, 1, strlen(pattern), pattern);
+
+            if ((error = xcb_request_check(conn, font_cookie)) != NULL)
+                errx(EXIT_FAILURE, "Could open neither requested font nor fallbacks "
+                     "(fixed or -misc-*): X11 error %d", error->error_code);
+        }
+    }
+
+    /* Get information (height/name) for this font */
+    if (!(info_reply = xcb_list_fonts_with_info_reply(conn, info_cookie, NULL)))
+        errx(EXIT_FAILURE, "Could not load font \"%s\"", pattern);
+
+    font.height = info_reply->font_ascent + info_reply->font_descent;
+
+    free(info_reply);
+
+    return font;
+}