Make sure the dragged window is smaller than work area in the target display

ash/wm/drag_window_resizer.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/wm/drag_window_resizer.h"
 
 #include "ash/display/mouse_cursor_event_filter.h"
 #include "ash/root_window_controller.h"
 #include "ash/screen_ash.h"
 #include "ash/shell.h"
@@ skipping 107 matching lines @@
   // Check if the destination is another display.
   gfx::Point last_mouse_location_in_screen = last_mouse_location_;
   wm::ConvertPointToScreen(GetTarget()->parent(),
                            &last_mouse_location_in_screen);
   gfx::Screen* screen = Shell::GetScreen();
   const gfx::Display dst_display =
       screen->GetDisplayNearestPoint(last_mouse_location_in_screen);
 
   if (dst_display.id() !=
       screen->GetDisplayNearestWindow(GetTarget()->GetRootWindow()).id()) {
-    const gfx::Rect dst_bounds =
-        ScreenAsh::ConvertRectToScreen(GetTarget()->parent(),
-                                       GetTarget()->bounds());
+    // Adjust the size and position so that it doesn't exceed the size of
+    // work area.
+    const gfx::Size& size = dst_display.work_area().size();
+    gfx::Rect bounds = GetTarget()->bounds();
+    if (bounds.width() > size.width()) {
+      int diff = bounds.width() - size.width();
+      bounds.set_x(bounds.x() + diff / 2);
+      bounds.set_width(size.width());
+    }
+    if (bounds.height() > size.height())
+      bounds.set_height(size.height());

[varkha, 2013/12/12 16:20:46]

Is this enough for a vertical arrangement where the secondary screen is above or
below the primary?

[oshima, 2013/12/12 19:07:14]

I don't think the screen layout does matter. I had to adjust a horizontal
position as you can drag using the left/right edge. Can we drag a window using
bottom edge?

[varkha, 2013/12/12 22:10:47]

I understand - we are probably never shrinking the window vertically enough to
get the title bar to be not under the cursor.

+
+    gfx::Rect dst_bounds =
+        ScreenAsh::ConvertRectToScreen(GetTarget()->parent(), bounds);
+
+    // Adjust the position so that the cursor is on the window.
+    if (!dst_bounds.Contains(last_mouse_location_in_screen)) {
+      if (last_mouse_location_in_screen.x() < dst_bounds.x())
+        dst_bounds.set_x(last_mouse_location_in_screen.x());
+      else if (last_mouse_location_in_screen.x() > dst_bounds.right())
+        dst_bounds.set_x(
+            last_mouse_location_in_screen.x() - dst_bounds.width());

[varkha, 2013/12/12 16:20:46]

Same here - does it consider vertical screen arrangement?

[varkha, 2013/12/12 22:10:47]

sg. Thanks for the explanation.

+    }
     GetTarget()->SetBoundsInScreen(dst_bounds, dst_display);
   }
 }
 
 void DragWindowResizer::RevertDrag() {
   next_window_resizer_->RevertDrag();
 
   drag_window_controller_.reset();
   GetTarget()->layer()->SetOpacity(details_.initial_opacity);
 }
@@ skipping 127 matching lines @@
   if (!tray_user->TransferWindowToUser(details_.window)) {
     GetTarget()->layer()->SetOpacity(old_opacity);
     return false;
   }
   RevertDrag();
   return true;
 }
 
 }  // namespace internal
 }  // namespace ash