Dont allow the user to 'resize a window out of the workarea'

ash/wm/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/window_resizer.h"
 
 #include "ash/screen_ash.h"
 #include "ash/shell.h"
 #include "ash/wm/property_util.h"
 #include "ash/wm/window_util.h"
+#include "ash/wm/workspace/workspace_layout_manager2.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/base/hit_test.h"
 #include "ui/base/ui_base_types.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/gfx/screen.h"
 
 namespace ash {
@@ skipping 141 matching lines @@
       break;
     default:
       break;
   }
   return bounds_change;
 }
 
 // static
 gfx::Rect WindowResizer::CalculateBoundsForDrag(
     const Details& details,
-    const gfx::Point& location) {
+    const gfx::Point& passed_location) {
   if (!details.is_resizable)
     return details.initial_bounds;
 
+  gfx::Point location = passed_location;
+  gfx::Rect work_area =
+      ScreenAsh::GetDisplayWorkAreaBoundsInParent(details.window);
+
   int delta_x = location.x() - details.initial_location_in_parent.x();
   int delta_y = location.y() - details.initial_location_in_parent.y();
 
   // The minimize size constraint may limit how much we change the window
   // position.  For example, dragging the left edge to the right should stop
   // repositioning the window when the minimize size is reached.
   gfx::Size size = GetSizeForDrag(details, &delta_x, &delta_y);
   gfx::Point origin = GetOriginForDrag(details, delta_x, delta_y);
+  gfx::Rect new_bounds(origin, size);
 
-  // When we might want to reposition a window which is also restored to its
-  // previous size, to keep the cursor within the dragged window.
-  if (!details.restore_bounds.IsEmpty() &&
-      details.bounds_change & kBoundsChange_Repositions) {
-    // However - it is not desirable to change the origin if the window would
-    // be still hit by the cursor.
-    if (details.initial_location_in_parent.x() >
-            details.initial_bounds.x() + details.restore_bounds.width())
-      origin.set_x(location.x() - details.restore_bounds.width() / 2);
+  // Sizing has to keep the result on the screen. Note that this correction
+  // has to come first since it might have an impact on the origin as well as
+  // on the size.
+  if (details.bounds_change & kBoundsChange_Resizes) {

[sky, 2012/10/16 22:57:46]

This code is logically similar to that of 245-250, right? Can't we expand the if
there to deal with this case?

[Mr4D (OOO till 08-26), 2012/10/17 00:05:17]

The thing is that a resize operation can change size and pos. If we do this
after the other pos changes below we will introduce an error.

That said, I was moving the sizing code up here before the moving correction
code.

+    if (details.size_change_direction & kBoundsChangeDirection_Horizontal) {
+      if (IsRightEdge(details.window_component) &&
+          new_bounds.right() < work_area.x() + kMinimumOnScreenArea) {
+        int delta = work_area.x() + kMinimumOnScreenArea - new_bounds.right();
+        new_bounds.set_width(new_bounds.width() + delta);
+      } else if (new_bounds.x() > work_area.right() - kMinimumOnScreenArea) {
+        int width = new_bounds.right() - work_area.right() +
+                    kMinimumOnScreenArea;
+        new_bounds.set_x(work_area.right() - kMinimumOnScreenArea);
+        new_bounds.set_width(width);
+      }
+    }
+    if (details.size_change_direction & kBoundsChangeDirection_Vertical) {

[sky, 2012/10/16 22:57:46]

Similarly should we fold 237-244 into this?

[Mr4D (OOO till 08-26), 2012/10/17 00:05:17]

Done.

+      if (!IsBottomEdge(details.window_component) &&
+          new_bounds.y() > work_area.bottom() - kMinimumOnScreenArea) {
+        int height = new_bounds.bottom() - work_area.bottom() +
+                     kMinimumOnScreenArea;
+        new_bounds.set_y(work_area.bottom() - kMinimumOnScreenArea);
+        new_bounds.set_height(height);
+      }
+    }
   }
 
-  gfx::Rect new_bounds(origin, size);
+  if (details.bounds_change & kBoundsChange_Repositions) {
+    // When we might want to reposition a window which is also restored to its
+    // previous size, to keep the cursor within the dragged window.
+    if (!details.restore_bounds.IsEmpty()) {
+      // However - it is not desirable to change the origin if the window would
+      // be still hit by the cursor.
+      if (details.initial_location_in_parent.x() >
+              details.initial_bounds.x() + details.restore_bounds.width())
+        new_bounds.set_x(location.x() - details.restore_bounds.width() / 2);
+    }
+    // Make sure that the x origin does not leave the screen. Note that y is
+    // taken care of next.
+    new_bounds.set_x(
+        std::max(work_area.x() - new_bounds.width() + kMinimumOnScreenArea,
+                 std::min(work_area.right() - kMinimumOnScreenArea,
+                          new_bounds.x())));
+  }
+
   // Update bottom edge to stay in the work area when we are resizing
-  // by dragging the bottome edge or corners.
+  // by dragging the bottom edge or corners.
   if (details.window_component == HTBOTTOM ||
       details.window_component == HTBOTTOMRIGHT ||
       details.window_component == HTBOTTOMLEFT) {
-    gfx::Rect work_area =
-        ScreenAsh::GetDisplayWorkAreaBoundsInParent(details.window);
     if (new_bounds.bottom() > work_area.bottom())
       new_bounds.Inset(0, 0, 0,
                        new_bounds.bottom() - work_area.bottom());
   }
   if (details.bounds_change & kBoundsChange_Resizes &&
       details.bounds_change & kBoundsChange_Repositions && new_bounds.y() < 0) {
     int delta = new_bounds.y();
     new_bounds.set_y(0);
     new_bounds.set_height(new_bounds.height() + delta);
   }
+
   return new_bounds;
 }
 
 // static
 bool WindowResizer::IsBottomEdge(int window_component) {
   return window_component == HTBOTTOMLEFT ||
       window_component == HTBOTTOM ||
       window_component == HTBOTTOMRIGHT ||
       window_component == HTGROWBOX;
 }
@@ skipping 79 matching lines @@
         details.window).bounds().height();
     if (height > max_height) {
       height = max_height;
       *delta_y = -y_multiplier * (details.initial_bounds.height() - max_height);
     }
   }
   return height;
 }
 
 }  // namespace aura