Center floating windows when tiling

config.h

@@ -42,7 +42,7 @@ static const int resizehints = 0;    /* 1 means respect size hints in tiled resi
 
 static const Layout layouts[] = {
 	/* symbol     arrange function */
-	{ "t",      tile },    /* first entry is default */
+	{ "t",      centerfloattile },    /* first entry is default */
 	{ "f",      NULL },    /* no layout function means floating behavior */
 	{ "m",      monocle },
 };

customfuncs.c

@@ -1,3 +1,15 @@
+void centerfloattile(Monitor *m) {
+	if (!m->sel) return;
+
+	if (m->sel->isfloating && !m->sel->isfullscreen && !m->sel->isfixed && m->sel->x == 0 && m->sel->y == 0) {
+		int x = (m->mw - m->sel->w) / 2;
+		int y = (m->mh - m->sel->h) / 2;
+		resize(m->sel, x, y, m->sel->w, m->sel->h, 0);
+	}
+
+	tile(m);
+}
+
 void togglefullscreen() {
 	if (selmon->sel == 0) {
 		return;