From: Egbert Eich <eich@suse.de>

DIX/ConfineTo: Improve algorithm to jump to the nearest point inside
    
ConfineToShape does not work well: The cursor often times doesn't jump
to the point closest to the current cursor position outside the shape.
This patch fixes this.

--- dix/events.c.orig	2012-04-17 11:34:39.714915372 -0500
+++ dix/events.c	2012-04-17 11:26:54.735728478 -0500
@@ -671,32 +671,77 @@
 {
     BoxRec box;
     int x = *px, y = *py;
-    int incx = 1, incy = 1;
+    int         nbox;
+    BoxPtr      pbox;
+    int                d, min = (~0U >> 1), dx2, dy2, x_r, y_r;
 
     if (RegionContainsPoint(shape, x, y, &box))
         return;
-    box = *RegionExtents(shape);
-    /* this is rather crude */
-    do {
-        x += incx;
-        if (x >= box.x2) {
-            incx = -1;
-            x = *px - 1;
+
+    for (nbox = REGION_NUM_RECTS (shape),
+            pbox = REGION_RECTS(shape);
+         nbox--;
+         pbox++)
+    {
+        if (pbox->x1 < x && pbox->x2 > x) {
+            d = pbox->y1 - y;
+            if (d >= 0) {
+                d *= d;
+                if (d < min) {
+                    *px = x;
+                    *py = pbox->y1 + 1;
+                    min = d;
+                }
+            } else {
+                d = pbox->y2 - y; d *= d;
+                if (d < min) {
+                    *px = x;
+                    *py = pbox->y2 - 1;
+                    min = d;
+                }
+            }
         }
-        else if (x < box.x1) {
-            incx = 1;
-            x = *px;
-            y += incy;
-            if (y >= box.y2) {
-                incy = -1;
-                y = *py - 1;
+        else if (pbox->y1 < y && pbox->y2 > y) {
+            d = pbox->x1 - x;
+            if (d >= 0) {
+                d *= d;
+                if (d < min) {
+                    *px = pbox->x1 + 1;
+                    *py = y;
+                    min = d;
+                }
+            } else {
+                d = pbox->x2 - x; d *= d;               
+                if (d < min) {
+                    *px = pbox->x2 - 1;
+                    *py = y;
+                    min = d;
+                }
+            }
+        } else {
+            dx2 = pbox->x1 - x; 
+            if (dx2 >= 0) {
+                dx2 *= dx2;
+                x_r = pbox->x1 + 1;
+            } else {
+                dx2 = pbox->x2 - x; dx2 *= dx2;
+                x_r = pbox->x2 - 1;
+            }
+            dy2 = pbox->y1 - y; 
+            if (dy2 >= 0) {
+                dy2 *= dy2;
+                y_r = pbox->y1 + 1;
+            } else {
+                dy2 = pbox->y2 - y; dy2 *= dy2;
+                y_r = pbox->y2 - 1;
+            }
+            if ((d = dx2 + dy2) < min) {
+                *px = x_r;
+                *py = y_r;
+                min = d;
             }
-            else if (y < box.y1)
-                return;         /* should never get here! */
         }
-    } while (!RegionContainsPoint(shape, x, y, &box));
-    *px = x;
-    *py = y;
+    }
 }
 
 static void