Stick windows to sides of workspaces

ash/wm/dock/docked_window_resizer.cc

+// Copyright (c) 2013 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/dock/docked_window_resizer.h"
+
+#include "ash/ash_switches.h"
+#include "ash/display/display_controller.h"
+#include "ash/launcher/launcher.h"
+#include "ash/root_window_controller.h"
+#include "ash/screen_ash.h"
+#include "ash/shelf/shelf_types.h"
+#include "ash/shelf/shelf_widget.h"
+#include "ash/shell.h"
+#include "ash/shell_window_ids.h"
+#include "ash/wm/coordinate_conversion.h"
+#include "ash/wm/dock/docked_window_layout_manager.h"
+#include "ash/wm/property_util.h"
+#include "ash/wm/window_properties.h"
+#include "ash/wm/workspace_controller.h"
+#include "base/command_line.h"
+#include "ui/aura/client/aura_constants.h"
+#include "ui/aura/env.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/gfx/screen.h"
+#include "ui/views/widget/widget.h"
+
+namespace ash {
+
+namespace {
+
+// How far we have to drag to undock a window.
+const int kSnapToDockDistance = 32;
+
+} // namespace
+
+DockedWindowResizer::~DockedWindowResizer() {
+}
+
+// static
+DockedWindowResizer*
+DockedWindowResizer::Create(WindowResizer* next_window_resizer,
+                            aura::Window* window,
+                            const gfx::Point& location,
+                            int window_component) {
+  Details details(window, location, window_component);
+  return details.is_resizable ?
+      new DockedWindowResizer(next_window_resizer, details) : NULL;
+}
+
+void DockedWindowResizer::Drag(const gfx::Point& location, int event_flags) {
+  last_mouse_location_ = location;
+  wm::ConvertPointToScreen(GetTarget()->parent(), &last_mouse_location_);
+  if (!did_move_or_resize_) {
+    did_move_or_resize_ = true;
+    StartedDragging();
+  }
+  gfx::Point offset;
+  gfx::Rect bounds(CalculateBoundsForDrag(details_, location));
+  MaybeSnapToSide(bounds, &offset);
+  gfx::Point modified_location(location.x() + offset.x(),
+                               location.y() + offset.y());
+  next_window_resizer_->Drag(modified_location, event_flags);
+}
+
+void DockedWindowResizer::CompleteDrag(int event_flags) {
+  // The root window can change when dragging into a different screen.
+  next_window_resizer_->CompleteDrag(event_flags);
+  FinishDragging();
+}
+
+void DockedWindowResizer::RevertDrag() {
+  next_window_resizer_->RevertDrag();
+  FinishDragging();
+}
+
+aura::Window* DockedWindowResizer::GetTarget() {
+  return next_window_resizer_->GetTarget();
+}
+
+DockedWindowResizer::DockedWindowResizer(WindowResizer* next_window_resizer,
+                                         const Details& details)
+    : details_(details),
+      next_window_resizer_(next_window_resizer),
+      dock_layout_(NULL),
+      did_move_or_resize_(false) {
+  DCHECK(details_.is_resizable);
+  aura::Window* dock_container = Shell::GetContainer(
+      details.window->GetRootWindow(),
+      internal::kShellWindowId_DockContainer);
+  DCHECK(dock_container->id() == internal::kShellWindowId_DockContainer);
+  dock_layout_ = static_cast<internal::DockedWindowLayoutManager*>(
+      dock_container->layout_manager());
+}
+
+void DockedWindowResizer::MaybeSnapToSide(const gfx::Rect& bounds,
+                                          gfx::Point* offset) {
+  aura::Window* dock_container = Shell::GetContainer(
+      wm::GetRootWindowAt(last_mouse_location_),
+      internal::kShellWindowId_DockContainer);
+  DCHECK(dock_container->id() == internal::kShellWindowId_DockContainer);
+  internal::DockedWindowLayoutManager* dock_layout =
+      static_cast<internal::DockedWindowLayoutManager*>(
+          dock_container->layout_manager());
+
+  internal::DockAlignment dock_alignment = dock_layout->alignment();
+  if (dock_alignment == internal::DOCK_ALIGNMENT_NONE) {
+    if (GetTarget() == dock_layout_->dragged_window())
+      dock_alignment = internal::DOCK_ALIGNMENT_ANY;
+    else
+      return;
+  }
+
+  gfx::Rect dock_bounds = ScreenAsh::ConvertRectFromScreen(
+      GetTarget()->parent(), dock_container->GetBoundsInScreen());
+
+  switch (dock_alignment) {
+    case internal::DOCK_ALIGNMENT_LEFT:
+      if (abs(bounds.x() - dock_bounds.x()) < kSnapToDockDistance)
+        offset->set_x(dock_bounds.x() - bounds.x());
+      break;
+    case internal::DOCK_ALIGNMENT_RIGHT:
+      if (abs(bounds.right() - dock_bounds.right()) < kSnapToDockDistance)
+        offset->set_x(dock_bounds.right() - bounds.right());
+      break;
+    case internal::DOCK_ALIGNMENT_ANY:
+      if (abs(bounds.x() - dock_bounds.x()) < kSnapToDockDistance)
+        offset->set_x(dock_bounds.x() - bounds.x());
+      if (abs(bounds.right() - dock_bounds.right()) < kSnapToDockDistance)
+        offset->set_x(dock_bounds.right() - bounds.right());
+      break;
+    case internal::DOCK_ALIGNMENT_NONE:
+      NOTREACHED() << "Nothing to do when no windows are docked";
+      break;
+  }
+}
+
+void DockedWindowResizer::StartedDragging() {
+  // Tell the dock layout manager that we are dragging this window.
+  dock_layout_->StartDragging(GetTarget());
+}
+
+void DockedWindowResizer::FinishDragging() {
+  if (!did_move_or_resize_)
+    return;
+
+  aura::Window* window = GetTarget();
+  bool should_dock = false;
+  if ((details_.bounds_change & WindowResizer::kBoundsChange_Repositions) &&
+      CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kAshEnableDockedWindows)) {
+    should_dock = internal::DockedWindowLayoutManager::ShouldWindowDock(
+        window, last_mouse_location_);
+  }
+
+  // Check if desired docked state is not same as current.
+  // If not same dock or undock accordingly.
+  if (should_dock !=
+      (window->parent()->id() == internal::kShellWindowId_DockContainer)) {
+    if (should_dock) {
+      aura::Window* dock_container = Shell::GetContainer(
+          window->GetRootWindow(),
+          internal::kShellWindowId_DockContainer);
+      dock_container->AddChild(window);
+    } else {
+      // Reparent the window back to workspace.
+      // We need to be careful to give SetDefaultParentByRootWindow location in
+      // the right root window (matching the logic in DragWindowResizer) based
+      // on which root window a mouse pointer is in. We want to undock into the
+      // right screen near the edge of a multiscreen setup (based on where the
+      // mouse is).
+      gfx::Rect near_last_mouse_location(last_mouse_location_, gfx::Size());
+      // Reparenting will cause Relayout and possible dock shrinking.
+      window->SetDefaultParentByRootWindow(window->GetRootWindow(),
+                                           near_last_mouse_location);
+      // A maximized workspace may be active so we may need to switch
+      // to a parent workspace of the window being dragged out.
+      internal::WorkspaceController* workspace_controller =
+          GetRootWindowController(
+              window->GetRootWindow())->workspace_controller();
+      workspace_controller->SetActiveWorkspaceByWindow(window);
+    }
+  }
+  dock_layout_->FinishDragging();
+}
+
+}  // namespace aura