M src/Window.cc → src/Window.cc

@@ -2537,25 +2537,61 @@ dright = std::abs(wleft - winrect.right()),
                dtop = std::abs(wbottom - winrect.top()),
             dbottom = std::abs(wtop - winrect.bottom());
 
-          // snap left?
+          // snap left of other window?
           if (dleft < snap_distance && dleft <= dright) {
             dx = winrect.left() - frame.rect.width();
+
+            // try corner-snap to its other sides
+            dtop = std::abs(wtop - winrect.top());
+            dbottom = std::abs(wbottom - winrect.bottom());
+            if (dtop < snap_distance && dtop <= dbottom)
+              dy = winrect.top();
+            else if (dbottom < snap_distance)
+              dy = winrect.bottom() - frame.rect.height();
+
             continue;
           }
-          // snap right?
+          // snap right of other window?
           else if (dright < snap_distance) {
             dx = winrect.right() + 1;
+
+            // try corner-snap to its other sides
+            dtop = std::abs(wtop - winrect.top());
+            dbottom = std::abs(wbottom - winrect.bottom());
+            if (dtop < snap_distance && dtop <= dbottom)
+              dy = winrect.top();
+            else if (dbottom < snap_distance)
+              dy = winrect.bottom() - frame.rect.height();
+
             continue;
           }
 
-          // snap top?
+          // snap top of other window?
           if (dtop < snap_distance && dtop <= dbottom) {
             dy = winrect.top() - frame.rect.height();
+
+            // try corner-snap to its other sides
+            dleft = std::abs(wleft - winrect.left());
+            dright = std::abs(wright - winrect.right());
+            if (dleft < snap_distance && dleft <= dright)
+              dx = winrect.left();
+            else if (dright < snap_distance)
+              dx = winrect.right() - frame.rect.width();
+
             continue;
           }
-          // snap bottom?
+          // snap bottom of other window?
           else if (dbottom < snap_distance) {
             dy = winrect.bottom() + 1;
+            
+            // try corner-snap to its other sides
+            dleft = std::abs(wleft - winrect.left());
+            dright = std::abs(wright - winrect.right());
+            if (dleft < snap_distance && dleft <= dright)
+              dx = winrect.left();
+            else if (dright < snap_distance)
+              dx = winrect.right() - frame.rect.width();
+
             continue;
           }
         }