ash/wm/window_positioner.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ash/wm/window_positioner.h"
   6
   7 #include "ash/screen_util.h"
   8 #include "ash/shell.h"
   9 #include "ash/shell_window_ids.h"
  10 #include "ash/wm/mru_window_tracker.h"
  11 #include "ash/wm/window_resizer.h"
  12 #include "ash/wm/window_state.h"
  13 #include "ash/wm/window_util.h"
  14 #include "ui/aura/window.h"
  15 #include "ui/aura/window_delegate.h"
  16 #include "ui/aura/window_event_dispatcher.h"
  17 #include "ui/compositor/layer.h"
  18 #include "ui/compositor/scoped_layer_animation_settings.h"
  19 #include "ui/gfx/screen.h"
  20 #include "ui/wm/core/window_animations.h"
  21 #include "ui/wm/core/window_util.h"
  22
  23 namespace ash {
  24
  25 const int WindowPositioner::kMinimumWindowOffset = 32;
  26
  27 // The number of pixels which are kept free top, left and right when a window
  28 // gets positioned to its default location.
  29 // static
  30 const int WindowPositioner::kDesktopBorderSize = 16;
  31
  32 // Maximum width of a window even if there is more room on the desktop.
  33 // static
  34 const int WindowPositioner::kMaximumWindowWidth = 1100;
  35
  36 namespace {
  37
  38 // When a window gets opened in default mode and the screen is less than or
  39 // equal to this width, the window will get opened in maximized mode. This value
  40 // can be reduced to a "tame" number if the feature is disabled.
  41 const int kForceMaximizeWidthLimit = 1366;
  42
  43 // The time in milliseconds which should be used to visually move a window
  44 // through an automatic "intelligent" window management option.
  45 const int kWindowAutoMoveDurationMS = 125;
  46
  47 // If set to true all window repositioning actions will be ignored. Set through
  48 // WindowPositioner::SetIgnoreActivations().
  49 static bool disable_auto_positioning = false;
  50
  51 // If set to true, by default the first window in ASH will be maximized.
  52 static bool maximize_first_window = false;
  53
  54 // Check if any management should be performed (with a given |window|).
  55 bool UseAutoWindowManager(const aura::Window* window) {
  56   if (disable_auto_positioning)
  57     return false;
  58   const wm::WindowState* window_state = wm::GetWindowState(window);
  59   return !window_state->is_dragged() && window_state->window_position_managed();
  60 }
  61
  62 // Check if a given |window| can be managed. This includes that it's state is
  63 // not minimized/maximized/the user has changed it's size by hand already.
  64 // It furthermore checks for the WindowIsManaged status.
  65 bool WindowPositionCanBeManaged(const aura::Window* window) {
  66   if (disable_auto_positioning)
  67     return false;
  68   const wm::WindowState* window_state = wm::GetWindowState(window);
  69   return window_state->window_position_managed() &&
  70       !window_state->IsMinimized() &&
  71       !window_state->IsMaximized() &&
  72       !window_state->bounds_changed_by_user();
  73 }
  74
  75 // Get the work area for a given |window| in parent coordinates.
  76 gfx::Rect GetWorkAreaForWindowInParent(aura::Window* window) {
  77 #if defined(OS_WIN)
  78   // On Win 8, the host window can't be resized, so
  79   // use window's bounds instead.
  80   // TODO(oshima): Emulate host window resize on win8.
  81   gfx::Rect work_area = gfx::Rect(window->parent()->bounds().size());
  82   work_area.Inset(Shell::GetScreen()->GetDisplayMatching(
  83       window->parent()->GetBoundsInScreen()).GetWorkAreaInsets());
  84   return work_area;
  85 #else
  86   return ScreenUtil::GetDisplayWorkAreaBoundsInParent(window);
  87 #endif
  88 }
  89
  90 // Move the given |bounds| on the available |work_area| in the direction
  91 // indicated by |move_right|. If |move_right| is true, the rectangle gets moved
  92 // to the right edge, otherwise to the left one.
  93 bool MoveRectToOneSide(const gfx::Rect& work_area,
  94                        bool move_right,
  95                        gfx::Rect* bounds) {
  96   if (move_right) {
  97     if (work_area.right() > bounds->right()) {
  98       bounds->set_x(work_area.right() - bounds->width());
  99       return true;
 100     }
 101   } else {
 102     if (work_area.x() < bounds->x()) {
 103       bounds->set_x(work_area.x());
 104       return true;
 105     }
 106   }
 107   return false;
 108 }
 109
 110 // Move a |window| to new |bounds|. Animate if desired by user.
 111 // Moves the transient children of the |window| as well by the same |offset| as
 112 // the parent |window|.
 113 void SetBoundsAndOffsetTransientChildren(aura::Window* window,
 114                                          const gfx::Rect& bounds,
 115                                          const gfx::Rect& work_area,
 116                                          const gfx::Vector2d& offset) {
 117   aura::Window::Windows transient_children =
 118       ::wm::GetTransientChildren(window);
 119   for (aura::Window::Windows::iterator iter = transient_children.begin();
 120       iter != transient_children.end(); ++iter) {
 121     aura::Window* transient_child = *iter;
 122     gfx::Rect child_bounds = transient_child->bounds();
 123     gfx::Rect new_child_bounds = child_bounds + offset;
 124     if ((child_bounds.x() <= work_area.x() &&
 125          new_child_bounds.x() <= work_area.x()) ||
 126         (child_bounds.right() >= work_area.right() &&
 127          new_child_bounds.right() >= work_area.right())) {
 128       continue;
 129     }
 130     if (new_child_bounds.right() > work_area.right())
 131       new_child_bounds.set_x(work_area.right() - bounds.width());
 132     else if (new_child_bounds.x() < work_area.x())
 133       new_child_bounds.set_x(work_area.x());
 134     SetBoundsAndOffsetTransientChildren(transient_child,
 135                                         new_child_bounds, work_area, offset);
 136   }
 137
 138   if (::wm::WindowAnimationsDisabled(window)) {
 139     window->SetBounds(bounds);
 140     return;
 141   }
 142
 143   ui::ScopedLayerAnimationSettings settings(window->layer()->GetAnimator());
 144   settings.SetTransitionDuration(
 145       base::TimeDelta::FromMilliseconds(kWindowAutoMoveDurationMS));
 146   window->SetBounds(bounds);
 147 }
 148
 149 // Move a |window| to new |bounds|. Animate if desired by user.
 150 // Note: The function will do nothing if the bounds did not change.
 151 void SetBoundsAnimated(aura::Window* window,
 152                        const gfx::Rect& bounds,
 153                        const gfx::Rect& work_area) {
 154   gfx::Rect old_bounds = window->GetTargetBounds();
 155   if (bounds == old_bounds)
 156     return;
 157   gfx::Vector2d offset(bounds.origin() - old_bounds.origin());
 158   SetBoundsAndOffsetTransientChildren(window, bounds, work_area, offset);
 159 }
 160
 161 // Move |window| into the center of the screen - or restore it to the previous
 162 // position.
 163 void AutoPlaceSingleWindow(aura::Window* window, bool animated) {
 164   gfx::Rect work_area = GetWorkAreaForWindowInParent(window);
 165   gfx::Rect bounds = window->bounds();
 166   const gfx::Rect* user_defined_area =
 167       wm::GetWindowState(window)->pre_auto_manage_window_bounds();
 168   if (user_defined_area) {
 169     bounds = *user_defined_area;
 170     ash::wm::AdjustBoundsToEnsureMinimumWindowVisibility(work_area, &bounds);
 171   } else {
 172     // Center the window (only in x).
 173     bounds.set_x(work_area.x() + (work_area.width() - bounds.width()) / 2);
 174   }
 175
 176   if (animated)
 177     SetBoundsAnimated(window, bounds, work_area);
 178   else
 179     window->SetBounds(bounds);
 180 }
 181
 182 // Get the first open (non minimized) window which is on the screen defined.
 183 aura::Window* GetReferenceWindow(const aura::Window* root_window,
 184                                  const aura::Window* exclude,
 185                                  bool *single_window) {
 186   if (single_window)
 187     *single_window = true;
 188   // Get the active window.
 189   aura::Window* active = ash::wm::GetActiveWindow();
 190   if (active && active->GetRootWindow() != root_window)
 191     active = NULL;
 192
 193   // Get a list of all windows.
 194   const std::vector<aura::Window*> windows = ash::Shell::GetInstance()->
 195       mru_window_tracker()->BuildWindowListIgnoreModal();
 196
 197   if (windows.empty())
 198     return NULL;
 199
 200   aura::Window::Windows::const_iterator iter = windows.begin();
 201   // Find the index of the current active window.
 202   if (active)
 203     iter = std::find(windows.begin(), windows.end(), active);
 204
 205   int index = (iter == windows.end()) ? 0 : (iter - windows.begin());
 206
 207   // Scan the cycle list backwards to see which is the second topmost window
 208   // (and so on). Note that we might cycle a few indices twice if there is no
 209   // suitable window. However - since the list is fairly small this should be
 210   // very fast anyways.
 211   aura::Window* found = NULL;
 212   for (int i = index + windows.size(); i >= 0; i--) {
 213     aura::Window* window = windows[i % windows.size()];
 214     while (::wm::GetTransientParent(window))
 215       window = ::wm::GetTransientParent(window);
 216     if (window != exclude && window->type() == ui::wm::WINDOW_TYPE_NORMAL &&
 217         window->GetRootWindow() == root_window && window->TargetVisibility() &&
 218         wm::GetWindowState(window)->window_position_managed()) {
 219       if (found && found != window) {
 220         // no need to check !single_window because the function must have
 221         // been already returned in the "if (!single_window)" below.
 222         *single_window = false;
 223         return found;
 224       }
 225       found = window;
 226       // If there is no need to check single window, return now.
 227       if (!single_window)
 228         return found;
 229     }
 230   }
 231   return found;
 232 }
 233
 234 }  // namespace
 235
 236 // static
 237 int WindowPositioner::GetForceMaximizedWidthLimit() {
 238   return kForceMaximizeWidthLimit;
 239 }
 240
 241 // static
 242 void WindowPositioner::GetBoundsAndShowStateForNewWindow(
 243     const gfx::Screen* screen,
 244     const aura::Window* new_window,
 245     bool is_saved_bounds,
 246     ui::WindowShowState show_state_in,
 247     gfx::Rect* bounds_in_out,
 248     ui::WindowShowState* show_state_out) {
 249
 250   // Always open new window in the target display.
 251   aura::Window* target = Shell::GetTargetRootWindow();
 252
 253   aura::Window* top_window = GetReferenceWindow(target, NULL, NULL);
 254   // Our window should not have any impact if we are already on top.
 255   if (top_window == new_window)
 256     top_window = NULL;
 257
 258   // If there is no valid other window we take and adjust the passed coordinates
 259   // and show state.
 260   if (!top_window) {
 261     gfx::Rect work_area = screen->GetDisplayNearestWindow(target).work_area();
 262
 263     bounds_in_out->AdjustToFit(work_area);
 264     // Use adjusted saved bounds, if there is one.
 265     if (is_saved_bounds)
 266       return;
 267     // When using "small screens" we want to always open in full screen mode.
 268     if (show_state_in == ui::SHOW_STATE_DEFAULT && (maximize_first_window ||
 269          (work_area.width() <= GetForceMaximizedWidthLimit() &&
 270          (!new_window || !wm::GetWindowState(new_window)->IsFullscreen())))) {
 271       *show_state_out = ui::SHOW_STATE_MAXIMIZED;
 272     }
 273     return;
 274   }
 275   wm::WindowState* top_window_state = wm::GetWindowState(top_window);
 276   bool maximized = top_window_state->IsMaximized();
 277   // We ignore the saved show state, but look instead for the top level
 278   // window's show state.
 279   if (show_state_in == ui::SHOW_STATE_DEFAULT) {
 280     *show_state_out = maximized ? ui::SHOW_STATE_MAXIMIZED :
 281         ui::SHOW_STATE_DEFAULT;
 282   }
 283
 284   if (maximized) {
 285     bool has_restore_bounds = top_window_state->HasRestoreBounds();
 286     if (has_restore_bounds) {
 287       // For a maximized window ignore the real bounds of the top level window
 288       // and use its restore bounds instead. Offset the bounds to prevent the
 289       // windows from overlapping exactly when restored.
 290       *bounds_in_out = top_window_state->GetRestoreBoundsInScreen() +
 291           gfx::Vector2d(kMinimumWindowOffset, kMinimumWindowOffset);
 292     }
 293     if (is_saved_bounds || has_restore_bounds) {
 294       gfx::Rect work_area = screen->GetDisplayNearestWindow(target).work_area();
 295       bounds_in_out->AdjustToFit(work_area);
 296       // Use adjusted saved bounds or restore bounds, if there is one.
 297       return;
 298     }
 299   }
 300
 301   // Use the size of the other window. The window's bound will be rearranged
 302   // in ash::WorkspaceLayoutManager using this location.
 303   *bounds_in_out = top_window->GetBoundsInScreen();
 304 }
 305
 306 // static
 307 void WindowPositioner::RearrangeVisibleWindowOnHideOrRemove(
 308     const aura::Window* removed_window) {
 309   if (!UseAutoWindowManager(removed_window))
 310     return;
 311   // Find a single open browser window.
 312   bool single_window;
 313   aura::Window* other_shown_window = GetReferenceWindow(
 314       removed_window->GetRootWindow(), removed_window, &single_window);
 315   if (!other_shown_window || !single_window ||
 316       !WindowPositionCanBeManaged(other_shown_window))
 317     return;
 318   AutoPlaceSingleWindow(other_shown_window, true);
 319 }
 320
 321 // static
 322 bool WindowPositioner::DisableAutoPositioning(bool ignore) {
 323   bool old_state = disable_auto_positioning;
 324   disable_auto_positioning = ignore;
 325   return old_state;
 326 }
 327
 328 // static
 329 void WindowPositioner::RearrangeVisibleWindowOnShow(
 330     aura::Window* added_window) {
 331   wm::WindowState* added_window_state = wm::GetWindowState(added_window);
 332   if (!added_window->TargetVisibility())
 333     return;
 334
 335   if (!UseAutoWindowManager(added_window) ||
 336       added_window_state->bounds_changed_by_user()) {
 337     if (added_window_state->minimum_visibility()) {
 338       // Guarantee minimum visibility within the work area.
 339       gfx::Rect work_area = GetWorkAreaForWindowInParent(added_window);
 340       gfx::Rect bounds = added_window->bounds();
 341       gfx::Rect new_bounds = bounds;
 342       ash::wm::AdjustBoundsToEnsureMinimumWindowVisibility(work_area,
 343                                                            &new_bounds);
 344       if (new_bounds != bounds)
 345         added_window->SetBounds(new_bounds);
 346     }
 347     return;
 348   }
 349   // Find a single open managed window.
 350   bool single_window;
 351   aura::Window* other_shown_window = GetReferenceWindow(
 352       added_window->GetRootWindow(), added_window, &single_window);
 353
 354   if (!other_shown_window) {
 355     // It could be that this window is the first window joining the workspace.
 356     if (!WindowPositionCanBeManaged(added_window) || other_shown_window)
 357       return;
 358     // Since we might be going from 0 to 1 window, we have to arrange the new
 359     // window to a good default.
 360     AutoPlaceSingleWindow(added_window, false);
 361     return;
 362   }
 363
 364   gfx::Rect other_bounds = other_shown_window->bounds();
 365   gfx::Rect work_area = GetWorkAreaForWindowInParent(added_window);
 366   bool move_other_right =
 367       other_bounds.CenterPoint().x() > work_area.x() + work_area.width() / 2;
 368
 369   // Push the other window to the size only if there are two windows left.
 370   if (single_window) {
 371     // When going from one to two windows both windows loose their
 372     // "positioned by user" flags.
 373     added_window_state->set_bounds_changed_by_user(false);
 374     wm::WindowState* other_window_state =
 375         wm::GetWindowState(other_shown_window);
 376     other_window_state->set_bounds_changed_by_user(false);
 377
 378     if (WindowPositionCanBeManaged(other_shown_window)) {
 379       // Don't override pre auto managed bounds as the current bounds
 380       // may not be original.
 381       if (!other_window_state->pre_auto_manage_window_bounds())
 382         other_window_state->SetPreAutoManageWindowBounds(other_bounds);
 383
 384       // Push away the other window after remembering its current position.
 385       if (MoveRectToOneSide(work_area, move_other_right, &other_bounds))
 386         SetBoundsAnimated(other_shown_window, other_bounds, work_area);
 387     }
 388   }
 389
 390   // Remember the current location of the window if it's new and push
 391   // it also to the opposite location if needed.  Since it is just
 392   // being shown, we do not need to animate it.
 393   gfx::Rect added_bounds = added_window->bounds();
 394   if (!added_window_state->pre_auto_manage_window_bounds())
 395     added_window_state->SetPreAutoManageWindowBounds(added_bounds);
 396   if (MoveRectToOneSide(work_area, !move_other_right, &added_bounds))
 397     added_window->SetBounds(added_bounds);
 398 }
 399
 400 WindowPositioner::WindowPositioner()
 401     : pop_position_offset_increment_x(0),
 402       pop_position_offset_increment_y(0),
 403       popup_position_offset_from_screen_corner_x(0),
 404       popup_position_offset_from_screen_corner_y(0),
 405       last_popup_position_x_(0),
 406       last_popup_position_y_(0) {
 407 }
 408
 409 WindowPositioner::~WindowPositioner() {
 410 }
 411
 412 gfx::Rect WindowPositioner::GetDefaultWindowBounds(
 413     const gfx::Display& display) {
 414   const gfx::Rect work_area = display.work_area();
 415   // There should be a 'desktop' border around the window at the left and right
 416   // side.
 417   int default_width = work_area.width() - 2 * kDesktopBorderSize;
 418   // There should also be a 'desktop' border around the window at the top.
 419   // Since the workspace excludes the tray area we only need one border size.
 420   int default_height = work_area.height() - kDesktopBorderSize;
 421   int offset_x = kDesktopBorderSize;
 422   if (default_width > kMaximumWindowWidth) {
 423     // The window should get centered on the screen and not follow the grid.
 424     offset_x = (work_area.width() - kMaximumWindowWidth) / 2;
 425     default_width = kMaximumWindowWidth;
 426   }
 427   return gfx::Rect(work_area.x() + offset_x,
 428                    work_area.y() + kDesktopBorderSize,
 429                    default_width,
 430                    default_height);
 431 }
 432
 433 gfx::Rect WindowPositioner::GetPopupPosition(const gfx::Rect& old_pos) {
 434   int grid = kMinimumWindowOffset;
 435   popup_position_offset_from_screen_corner_x = grid;
 436   popup_position_offset_from_screen_corner_y = grid;
 437   if (!pop_position_offset_increment_x) {
 438     // When the popup position increment is 0, the last popup position
 439     // was not yet initialized.
 440     last_popup_position_x_ = popup_position_offset_from_screen_corner_x;
 441     last_popup_position_y_ = popup_position_offset_from_screen_corner_y;
 442   }
 443   pop_position_offset_increment_x = grid;
 444   pop_position_offset_increment_y = grid;
 445   // We handle the Multi monitor support by retrieving the active window's
 446   // work area.
 447   aura::Window* window = wm::GetActiveWindow();
 448   const gfx::Rect work_area = window && window->IsVisible() ?
 449       Shell::GetScreen()->GetDisplayNearestWindow(window).work_area() :
 450       Shell::GetScreen()->GetPrimaryDisplay().work_area();
 451   // Only try to reposition the popup when it is not spanning the entire
 452   // screen.
 453   if ((old_pos.width() + popup_position_offset_from_screen_corner_x >=
 454       work_area.width()) ||
 455       (old_pos.height() + popup_position_offset_from_screen_corner_y >=
 456        work_area.height()))
 457     return AlignPopupPosition(old_pos, work_area, grid);
 458   const gfx::Rect result = SmartPopupPosition(old_pos, work_area, grid);
 459   if (!result.IsEmpty())
 460     return AlignPopupPosition(result, work_area, grid);
 461   return NormalPopupPosition(old_pos, work_area);
 462 }
 463
 464 // static
 465 void WindowPositioner::SetMaximizeFirstWindow(bool maximize) {
 466   maximize_first_window = maximize;
 467 }
 468
 469 gfx::Rect WindowPositioner::NormalPopupPosition(
 470     const gfx::Rect& old_pos,
 471     const gfx::Rect& work_area) {
 472   int w = old_pos.width();
 473   int h = old_pos.height();
 474   // Note: The 'last_popup_position' is checked and kept relative to the
 475   // screen size. The offsetting will be done in the last step when the
 476   // target rectangle gets returned.
 477   bool reset = false;
 478   if (last_popup_position_y_ + h > work_area.height() ||
 479       last_popup_position_x_ + w > work_area.width()) {
 480     // Popup does not fit on screen. Reset to next diagonal row.
 481     last_popup_position_x_ -= last_popup_position_y_ -
 482                               popup_position_offset_from_screen_corner_x -
 483                               pop_position_offset_increment_x;
 484     last_popup_position_y_ = popup_position_offset_from_screen_corner_y;
 485     reset = true;
 486   }
 487   if (last_popup_position_x_ + w > work_area.width()) {
 488     // Start again over.
 489     last_popup_position_x_ = popup_position_offset_from_screen_corner_x;
 490     last_popup_position_y_ = popup_position_offset_from_screen_corner_y;
 491     reset = true;
 492   }
 493   int x = last_popup_position_x_;
 494   int y = last_popup_position_y_;
 495   if (!reset) {
 496     last_popup_position_x_ += pop_position_offset_increment_x;
 497     last_popup_position_y_ += pop_position_offset_increment_y;
 498   }
 499   return gfx::Rect(x + work_area.x(), y + work_area.y(), w, h);
 500 }
 501
 502 gfx::Rect WindowPositioner::SmartPopupPosition(
 503     const gfx::Rect& old_pos,
 504     const gfx::Rect& work_area,
 505     int grid) {
 506   const std::vector<aura::Window*> windows = ash::Shell::GetInstance()->
 507       mru_window_tracker()->BuildWindowListIgnoreModal();
 508
 509   std::vector<const gfx::Rect*> regions;
 510   // Process the window list and check if we can bail immediately.
 511   for (size_t i = 0; i < windows.size(); i++) {
 512     // We only include opaque and visible windows.
 513     if (windows[i] && windows[i]->IsVisible() && windows[i]->layer() &&
 514         (!windows[i]->transparent() ||
 515          windows[i]->layer()->GetTargetOpacity() == 1.0)) {
 516       wm::WindowState* window_state = wm::GetWindowState(windows[i]);
 517       // When any window is maximized we cannot find any free space.
 518       if (window_state->IsMaximizedOrFullscreen())
 519         return gfx::Rect(0, 0, 0, 0);
 520       if (window_state->IsNormalOrSnapped())
 521         regions.push_back(&windows[i]->bounds());
 522     }
 523   }
 524
 525   if (regions.empty())
 526     return gfx::Rect(0, 0, 0, 0);
 527
 528   int w = old_pos.width();
 529   int h = old_pos.height();
 530   int x_end = work_area.width() / 2;
 531   int x, x_increment;
 532   // We parse for a proper location on the screen. We do this in two runs:
 533   // The first run will start from the left, parsing down, skipping any
 534   // overlapping windows it will encounter until the popup's height can not
 535   // be served anymore. Then the next grid position to the right will be
 536   // taken, and the same cycle starts again. This will be repeated until we
 537   // hit the middle of the screen (or we find a suitable location).
 538   // In the second run we parse beginning from the right corner downwards and
 539   // then to the left.
 540   // When no location was found, an empty rectangle will be returned.
 541   for (int run = 0; run < 2; run++) {
 542     if (run == 0) { // First run: Start left, parse right till mid screen.
 543       x = 0;
 544       x_increment = pop_position_offset_increment_x;
 545     } else { // Second run: Start right, parse left till mid screen.
 546       x = work_area.width() - w;
 547       x_increment = -pop_position_offset_increment_x;
 548     }
 549     // Note: The passing (x,y,w,h) window is always relative to the work area's
 550     // origin.
 551     for (; x_increment > 0 ? (x < x_end) : (x > x_end); x += x_increment) {
 552       int y = 0;
 553       while (y + h <= work_area.height()) {
 554         size_t i;
 555         for (i = 0; i < regions.size(); i++) {
 556           if (regions[i]->Intersects(gfx::Rect(x + work_area.x(),
 557                                                y + work_area.y(), w, h))) {
 558             y = regions[i]->bottom() - work_area.y();
 559             break;
 560           }
 561         }
 562         if (i >= regions.size())
 563           return gfx::Rect(x + work_area.x(), y + work_area.y(), w, h);
 564       }
 565     }
 566   }
 567   return gfx::Rect(0, 0, 0, 0);
 568 }
 569
 570 gfx::Rect WindowPositioner::AlignPopupPosition(
 571     const gfx::Rect& pos,
 572     const gfx::Rect& work_area,
 573     int grid) {
 574   if (grid <= 1)
 575     return pos;
 576
 577   int x = pos.x() - (pos.x() - work_area.x()) % grid;
 578   int y = pos.y() - (pos.y() - work_area.y()) % grid;
 579   int w = pos.width();
 580   int h = pos.height();
 581
 582   // If the alignment was pushing the window out of the screen, we ignore the
 583   // alignment for that call.
 584   if (abs(pos.right() - work_area.right()) < grid)
 585     x = work_area.right() - w;
 586   if (abs(pos.bottom() - work_area.bottom()) < grid)
 587     y = work_area.bottom() - h;
 588   return gfx::Rect(x, y, w, h);
 589 }
 590
 591 }  // namespace ash