From b1c0faab896040ec411f0c38a85df1d0ab061f4e Mon Sep 17 00:00:00 2001
From: "Michael D. Lowis" <mike.lowis@gentex.com>
Date: Thu, 12 Mar 2020 09:56:15 -0400
Subject: [PATCH] added logic to find closest monitor and associate the window
 with that monitor

---
 anvil.h  |  3 ++-
 build.sh |  2 +-
 client.c |  1 +
 mons.c   | 39 ++++++++++++++++++++++++++++++++++++---
 4 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/anvil.h b/anvil.h
index ed23540..1097b42 100644
--- a/anvil.h
+++ b/anvil.h
@@ -38,7 +38,7 @@ typedef struct Workspace {
 
 typedef struct Monitor {
     struct Monitor* next;
-    int x, y, w, h;
+    int x, y, w, h, midx, midy;
     Workspace* wspaces;
     Workspace* cspace;
 } Monitor;
@@ -61,6 +61,7 @@ void mons_init(void);
 void mons_addclient(Client* c);
 void mons_delclient(Client* c);
 int mons_find(Window win, Location* loc);
+void mons_place(Client* c);
 
 /* client.c */
 extern Client* Focused;
diff --git a/build.sh b/build.sh
index 6b0dfdc..2b940aa 100755
--- a/build.sh
+++ b/build.sh
@@ -1,4 +1,4 @@
 #!/bin/sh
-cc -g -Wall -Wextra -Werror -o anvil *.c -lX11 -lXinerama
+cc -g -Wall -Wextra -Werror -o anvil *.c -lX11 -lXinerama -lm
 ctags *
 grep -n 'TODO' *.c | sed -e 's/: \+/: /' -e 's/\/\* *//g' -e 's/ *\*\/$//' -e 's/TODO: *//'
\ No newline at end of file
diff --git a/client.c b/client.c
index 26c3d9e..557f2ea 100644
--- a/client.c
+++ b/client.c
@@ -117,6 +117,7 @@ void client_move(Client* c, int xdiff, int ydiff)
         c->x - BORDER_WIDTH,
         c->y - TITLE_HEIGHT - BORDER_WIDTH);
     XSync(X.disp, False);
+    mons_place(c);
 }
 
 void client_resize(Client* c, int xdiff, int ydiff)
diff --git a/mons.c b/mons.c
index 8a909b3..0d47a7b 100644
--- a/mons.c
+++ b/mons.c
@@ -1,4 +1,5 @@
 #include "anvil.h"
+#include <math.h>
 
 Monitor* Monitors = NULL;
 
@@ -16,6 +17,8 @@ void mons_init(void)
         m->y = mons[i].y_org;
         m->w = mons[i].width;
         m->h = mons[i].height;
+        m->midx = m->x + m->w/2;
+        m->midy = m->y + m->h/2;
         m->next = Monitors;
         Monitors = m;
     }
@@ -28,7 +31,8 @@ void mons_addclient(Client* c)
     /* for now just add it to the first monitor in the list */
     c->next = Monitors->cspace->floating;
     Monitors->cspace->floating = c;
-    /* TODO: use size and position to pick the "right" monitor */
+    /* now find the best one based on distance to midpoint */
+    mons_place(c);
 }
 
 Client* delclient(Client* list, Client* dead)
@@ -58,10 +62,9 @@ void mons_delclient(Client* c)
 
 int mons_find(Window win, Location* loc)
 {
-    Monitor* mons = Monitors;
     for (Monitor* mon = Monitors; mon; mon = mon->next)
     {
-        for (Workspace* wspace = mons->wspaces; wspace; wspace = wspace->next)
+        for (Workspace* wspace = mon->wspaces; wspace; wspace = wspace->next)
         {
             for (Client* client = wspace->floating; client; client = client->next)
             {
@@ -77,3 +80,33 @@ int mons_find(Window win, Location* loc)
     }
     return 0;
 }
+
+void mons_place(Client* c)
+{
+    Location loc;
+    if (mons_find(c->win, &loc))
+    {
+        int mindist = 0;
+        Monitor* closest = NULL;
+        /* find the closest monitor by calculating distance between midpoints */
+        int midx = (c->x - BORDER_WIDTH) + (c->w + 2*BORDER_WIDTH)/2;
+        int midy = (c->y - BORDER_WIDTH - TITLE_HEIGHT) + (c->h + 2*BORDER_WIDTH + TITLE_HEIGHT)/2;
+        for (Monitor* mon = Monitors; mon; mon = mon->next)
+        {
+            /* dist = sqrt((x2-x1)^2 + (y2-y1)^2) */
+            int dist = sqrt((midx - mon->midx)*(midx - mon->midx) + (midy - mon->midy)*(midy - mon->midy));
+            if (!closest || dist < mindist)
+            {
+                closest = mon;
+                mindist = dist;
+            }
+        }
+        /* if we changed monitiors, make sure we update accordingly */
+        if (loc.monitor != closest)
+        {
+            loc.workspace->floating = delclient(loc.workspace->floating, c);
+            c->next = closest->cspace->floating;
+            closest->cspace->floating = c;
+        }
+    }
+}
\ No newline at end of file
-- 
2.52.0