center patch: adding options to center transient windows

dwm.c

@@ -2318,6 +2318,13 @@ manage(Window w, XWindowAttributes *wa)
 		c->bw = borderpx;
 		#endif // SETBORDERPX_PATCH
 		#endif // FLOATPOS_PATCH
+		#if CENTER_TRANSIENT_WINDOWS_BY_PARENT_PATCH
+		c->x = t->x + WIDTH(t) / 2 - WIDTH(c) / 2;
+		c->y = t->y + HEIGHT(t) / 2 - HEIGHT(c) / 2;
+		#elif CENTER_TRANSIENT_WINDOWS_PATCH
+		c->x = c->mon->wx + (c->mon->ww - WIDTH(c)) / 2;
+		c->y = c->mon->wy + (c->mon->wh - HEIGHT(c)) / 2;
+		#endif // CENTER_TRANSIENT_WINDOWS_PATCH | CENTER_TRANSIENT_WINDOWS_BY_PARENT_PATCH
 	} else {
 		c->mon = selmon;
 		#if FLOATPOS_PATCH

patches.def.h

@@ -103,6 +103,23 @@
  */
 #define CENTER_PATCH 0
 
+/* A transient window is one that is meant to be short lived and is usually raised by a
+ * parent window. Such windows are typically dialog boxes and the like.
+ * It should be noted that in dwm transient windows are not subject to normal client rules
+ * and they are always floating by default.
+ * This patch centers transient windows on the screen like the center patch does. Note that
+ * the 6.2 center patch piggy-backed on the updatewindowtype function to ensure that all
+ * dialog boxes were centered, transient or not. This function was removed in relation to
+ * adding wintype as a client rule filter, hence this no longer works out of the box. This
+ * patch restores previous behaviour with the center patch.
+ */
+#define CENTER_TRANSIENT_WINDOWS_PATCH 0
+
+/* As above, except that the transient window is centered within the position of the parent
+ * window, rather than at the center of the screen. This takes precedence over the above patch.
+ */
+#define CENTER_TRANSIENT_WINDOWS_BY_PARENT_PATCH 0
+
 /* This patch centers the WM_NAME of the currently selected window on the status bar.
  * Both fancybar and awesomebar patches take precedence over this patch.
  * https://dwm.suckless.org/patches/centeredwindowname/