Adding sortscreens patch

README.md

@@ -13,6 +13,8 @@ Refer to [https://dwm.suckless.org/](https://dwm.suckless.org/) for details on t
 
 ### Changelog:
 
+2019-10-07 - Added sortscreens patch
+
 2019-10-06 - Added statuscolors and statusallmons patches, fixed minor cross-compatibility issues for killunsel, fullscreen, noborder, tagintostack patches
 
 2019-10-05 - Added killunsel, taggrid, hidevacanttags and cmdcustomize patches
@@ -192,6 +194,9 @@ Refer to [https://dwm.suckless.org/](https://dwm.suckless.org/) for details on t
    - [setborderpx](https://dwm.suckless.org/patches/statuspadding/)
       - this patch allows border pixels to be changed during runtime
 
+   - [sortscreens](https://www.mail-archive.com/hackers@suckless.org/msg09400.html)
+      - this patch aims to address some inconsistencies when it comes to focusmon, tagmon and similar functionality by explicitly sorting screens left to right (or top to bottom in a vertical layout)
+
    - [statusallmons](https://dwm.suckless.org/patches/statuspadding/)
       - this patch draws and updates the statusbar on all monitors
 

dwm.c

@@ -3104,6 +3104,9 @@ updategeom(void)
 				memcpy(&unique[j++], &info[i], sizeof(XineramaScreenInfo));
 		XFree(info);
 		nn = j;
+		#if SORTSCREENS_PATCH
+		sortscreens(unique, nn);
+		#endif // SORTSCREENS_PATCH
 		if (n <= nn) { /* new monitors available */
 			for (i = 0; i < (nn - n); i++) {
 				for (m = mons; m && m->next; m = m->next);

patch/include.c

@@ -94,6 +94,12 @@
 #include "setborderpx.c"
 #endif
 
+#ifdef XINERAMA
+#if SORTSCREENS_PATCH
+#include "sortscreens.c"
+#endif
+#endif
+
 #if STICKY_PATCH
 #include "sticky.c"
 #endif

patch/include.h

@@ -94,6 +94,12 @@
 #include "setborderpx.h"
 #endif
 
+#ifdef XINERAMA
+#if SORTSCREENS_PATCH
+#include "sortscreens.h"
+#endif
+#endif
+
 #if STICKY_PATCH
 #include "sticky.h"
 #endif

patch/sortscreens.c

@@ -0,0 +1,15 @@
+void
+sortscreens(XineramaScreenInfo *screens, int n)
+{
+       int i, j;
+       XineramaScreenInfo *screen = ecalloc(1, sizeof(XineramaScreenInfo));
+
+       for (i = 0; i < n; i++)
+               for (j = i + 1; j < n; j++)
+                       if (RIGHTOF(screens[i], screens[j])) {
+                               memcpy(&screen[0], &screens[i], sizeof(XineramaScreenInfo));
+                               memcpy(&screens[i], &screens[j], sizeof(XineramaScreenInfo));
+                               memcpy(&screens[j], &screen[0], sizeof(XineramaScreenInfo));
+                       }
+       XFree(screen);
+}

patch/sortscreens.h

@@ -0,0 +1,3 @@
+#define RIGHTOF(a,b) (a.y_org > b.y_org) || ((a.y_org == b.y_org) && (a.x_org > b.x_org))
+
+static void sortscreens(XineramaScreenInfo *screens, int n);

patches.h

@@ -298,6 +298,14 @@
  */
 #define SETBORDERPX_PATCH 0
 
+/* In a multi-head setup monitor 0 is by default the primary screen, with the left and right
+ * screen being monitor 1 and 2 respectively. This patch sorts screens left to right (or
+ * top to bottom in a vertical layout) which aims to address some inconsistencies when it
+ * comes to focusmon, tagmon and similar functionality.
+ * https://www.mail-archive.com/hackers@suckless.org/msg09400.html
+ */
+#define SORTSCREENS_PATCH 0
+
 /* This patch draws and updates the statusbar on all monitors.
  * https://dwm.suckless.org/patches/statusallmons/
  */