Implement workspace scrubbing

BUG=160903
Test=Manual

Review URL: https://chromiumcodereview.appspot.com/11417150

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@170688 0039d316-1c4b-4281-b951-d872f2087c98

ash/ash.gyp

@@ -403,6 +403,8 @@
         'wm/workspace/workspace.h',
         'wm/workspace/workspace_animations.cc',
         'wm/workspace/workspace_animations.h',
+        'wm/workspace/workspace_cycler.cc',
+        'wm/workspace/workspace_cycler.h',
         'wm/workspace/workspace_event_handler.cc',
         'wm/workspace/workspace_event_handler.h',
         'wm/workspace/workspace_layout_manager.cc',

ash/ash_switches.cc

@@ -46,6 +46,9 @@ const char kAshDisablePanelFitting[] = "ash-disable-panel-fitting";
 // Enable advanced gestures (e.g. for window management).
 const char kAshEnableAdvancedGestures[] = "ash-enable-advanced-gestures";
 
+// Enable workspace switching via a three finger vertical scroll.
+const char kAshEnableWorkspaceScrubbing[] = "ash-enable-workspace-scrubbing";
+
 #if defined(OS_LINUX)
 // Enable memory monitoring.
 const char kAshEnableMemoryMonitor[] = "ash-enable-memory-monitor";

ash/ash_switches.h

@@ -33,6 +33,7 @@ ASH_EXPORT extern const char kAshEnableMemoryMonitor[];
 ASH_EXPORT extern const char kAshEnablePerAppLauncher[];
 ASH_EXPORT extern const char kAshEnableOak[];
 ASH_EXPORT extern const char kAshEnableTrayDragging[];
+ASH_EXPORT extern const char kAshEnableWorkspaceScrubbing[];
 ASH_EXPORT extern const char kAshImmersive[];
 ASH_EXPORT extern const char kAshLauncherPerDisplay[];
 ASH_EXPORT extern const char kAshNewLockAnimationsEnabled[];

ash/wm/workspace/workspace_cycler.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/workspace/workspace_cycler.h"
+
+#include "ash/shell.h"
+#include "ash/wm/workspace/workspace_manager.h"
+#include "ui/base/events/event.h"
+#include "ui/base/events/event_utils.h"
+
+namespace ash {
+namespace internal {
+
+namespace {
+
+// The required vertical distance to scrub to the next workspace.
+const int kWorkspaceStepSize = 10;
+
+// Returns true is scrubbing is enabled.
+bool IsScrubbingEnabled() {
+  // Scrubbing is disabled if the screen is locked or a modal dialog is open.
+  return !Shell::GetInstance()->IsScreenLocked() &&
+         !Shell::GetInstance()->IsSystemModalWindowOpen();
+}
+
+}  // namespace
+
+WorkspaceCycler::WorkspaceCycler(WorkspaceManager* workspace_manager)
+    : workspace_manager_(workspace_manager),
+      scrubbing_(false),
+      scroll_x_(0),
+      scroll_y_(0) {
+  ash::Shell::GetInstance()->AddPreTargetHandler(this);
+}
+
+WorkspaceCycler::~WorkspaceCycler() {
+  scrubbing_ = false;
+  ash::Shell::GetInstance()->RemovePreTargetHandler(this);
+}
+
+ui::EventResult WorkspaceCycler::OnScrollEvent(ui::ScrollEvent* event) {
+  if (event->finger_count() != 3 ||
+      event->type() != ui::ET_SCROLL) {
+    scrubbing_ = false;
+    return ui::ER_UNHANDLED;
+  }
+
+  if (!IsScrubbingEnabled()) {
+    scrubbing_ = false;
+    return ui::ER_UNHANDLED;
+  }
+
+  if (!scrubbing_) {
+    scrubbing_ = true;
+    scroll_x_ = 0;
+    scroll_y_ = 0;
+  }
+
+  if (ui::IsNaturalScrollEnabled()) {
+    scroll_x_ += event->x_offset();
+    scroll_y_ += event->y_offset();
+  } else {
+    scroll_x_ -= event->x_offset();
+    scroll_y_ -= event->y_offset();
+  }
+
+  // TODO(pkotwicz): Implement scrubbing through several workspaces as the
+  // result of a single scroll event.
+  if (std::abs(scroll_y_) > kWorkspaceStepSize) {
+    workspace_manager_->CycleToWorkspace(scroll_y_ > 0 ?
+        WorkspaceManager::CYCLE_NEXT : WorkspaceManager::CYCLE_PREVIOUS);
+
+    scroll_x_ = 0;
+    scroll_y_ = 0;
+    return ui::ER_HANDLED;
+  }
+
+  if (std::abs(scroll_x_) > kWorkspaceStepSize) {
+    // Update |scroll_x_| and |scroll_y_| such that workspaces are only cycled
+    // through when there recently was a significant amount of vertical movement
+    // as opposed to vertical movement accumulated over a long horizontal three
+    // finger scroll.
+    scroll_x_ = 0;
+    scroll_y_ = 0;
+  }
+
+  // The active workspace was not changed, do not consume the event.
+  return ui::ER_UNHANDLED;
+}
+
+}  // namespace internal
+}  // namespace ash

ash/wm/workspace/workspace_cycler.h

+// 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.
+
+#ifndef ASH_WM_WORKSPACE_WORKSPACE_CYCLER_H_
+#define ASH_WM_WORKSPACE_WORKSPACE_CYCLER_H_
+
+#include "ash/ash_export.h"
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "ui/base/events/event_handler.h"
+
+namespace ash {
+namespace internal {
+
+class WorkspaceManager;
+
+// Class to enable quick workspace switching (scrubbing) via 3 finger vertical
+// scroll.
+class ASH_EXPORT WorkspaceCycler : public ui::EventHandler {
+ public:
+  explicit WorkspaceCycler(WorkspaceManager* workspace_manager);
+  virtual ~WorkspaceCycler();
+
+ private:
+  // ui::EventHandler overrides:
+  virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
+
+  WorkspaceManager* workspace_manager_;
+
+  // Whether the user is scrubbing through workspaces.
+  bool scrubbing_;
+
+  // The amount of scrolling which has occurred since the last time the
+  // workspace was switched. If scrubbing has just begun, |scroll_x_| and
+  // |scroll_y_| are set to 0.
+  int scroll_x_;
+  int scroll_y_;
+
+  DISALLOW_COPY_AND_ASSIGN(WorkspaceCycler);
+};
+
+}  // namespace internal
+}  // namespace ash
+
+#endif  // ASH_WM_WORKSPACE_WORKSPACE_CYCLER_H_

ash/wm/workspace/workspace_manager.cc

@@ -262,6 +262,33 @@ Window* WorkspaceManager::GetParentForNewWindow(Window* window) {
   return desktop_workspace()->window();
 }
 
+bool WorkspaceManager::CycleToWorkspace(CycleDirection direction) {
+  aura::Window* active_window = wm::GetActiveWindow();
+  if (!active_workspace_->window()->Contains(active_window))
+    active_window = NULL;
+
+  Workspaces::const_iterator workspace_i(FindWorkspace(active_workspace_));
+  int workspace_offset = 0;
+  if (direction == CYCLE_PREVIOUS) {
+    workspace_offset = 1;
+    if (workspace_i == workspaces_.end() - 1)
+      return false;
+  } else {
+    workspace_offset = -1;
+    if (workspace_i == workspaces_.begin())
+      return false;
+  }
+
+  Workspaces::const_iterator next_workspace_i(workspace_i + workspace_offset);
+  SetActiveWorkspace(*next_workspace_i, SWITCH_OTHER, base::TimeDelta());
+
+  // The activation controller will pick a window from the just activated
+  // workspace to activate as a result of DeactivateWindow().
+  if (active_window)
+    wm::DeactivateWindow(active_window);
+  return true;
+}
+
 void WorkspaceManager::DoInitialAnimation() {
   if (active_workspace_->is_maximized()) {
     RootWindowController* root_controller = GetRootWindowController(

ash/wm/workspace/workspace_manager.h

@@ -53,6 +53,11 @@ class Workspace;
 // are maximized and restored they are reparented to the right Window.
 class ASH_EXPORT WorkspaceManager : public ash::ShellObserver {
  public:
+  enum CycleDirection {
+    CYCLE_NEXT,
+    CYCLE_PREVIOUS
+  };
+
   explicit WorkspaceManager(aura::Window* viewport);
   virtual ~WorkspaceManager();
 
@@ -78,6 +83,11 @@ class ASH_EXPORT WorkspaceManager : public ash::ShellObserver {
   // when a new Window is being added.
   aura::Window* GetParentForNewWindow(aura::Window* window);
 
+  // Called by the workspace cycler to activate the next workspace in
+  // |direction|. Returns false if there are no more workspaces to cycle
+  // to in |direction|.
+  bool CycleToWorkspace(CycleDirection direction);
+
   // Starts the animation that occurs on first login.
   void DoInitialAnimation();
 

ash/wm/workspace_controller.cc

@@ -6,6 +6,7 @@
 
 #include "ash/ash_switches.h"
 #include "ash/wm/window_util.h"
+#include "ash/wm/workspace/workspace_cycler.h"
 #include "ash/wm/workspace/workspace_manager.h"
 #include "base/command_line.h"
 #include "ui/aura/client/activation_client.h"
@@ -17,9 +18,14 @@ namespace ash {
 namespace internal {
 
 WorkspaceController::WorkspaceController(aura::Window* viewport)
-    : viewport_(viewport) {
+    : viewport_(viewport),
+      workspace_cycler_(NULL) {
   aura::RootWindow* root_window = viewport->GetRootWindow();
   workspace_manager_.reset(new WorkspaceManager(viewport));
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kAshEnableWorkspaceScrubbing)) {
+    workspace_cycler_.reset(new WorkspaceCycler(workspace_manager_.get()));
+  }
   aura::client::GetActivationClient(root_window)->AddObserver(this);
 }
 

ash/wm/workspace_controller.h

@@ -20,6 +20,7 @@ namespace internal {
 
 class ShelfLayoutManager;
 class WorkspaceControllerTestHelper;
+class WorkspaceCycler;
 class WorkspaceEventHandler;
 class WorkspaceManager;
 
@@ -56,6 +57,10 @@ class ASH_EXPORT WorkspaceController
 
   scoped_ptr<WorkspaceManager> workspace_manager_;
 
+  // Cycles through the WorkspaceManager's workspaces in response to a three
+  // finger vertical scroll.
+  scoped_ptr<WorkspaceCycler> workspace_cycler_;
+
   DISALLOW_COPY_AND_ASSIGN(WorkspaceController);
 };
 

chrome/app/generated_resources.grd

@@ -6726,11 +6726,17 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_FLAGS_ENABLE_ADVANCED_GESTURES_DESCRIPTION" desc="Title for the flag to enable advanced gestures.">
         Enables advanced gestures (e.g. 4-finger pinch to minimize window etc.).
       </message>
-      <message name="IDS_FLAGS_ENABLE_TAB_SCRUBBING_NAME" desc="Title for the flag to enable advanced gestures.">
+      <message name="IDS_FLAGS_ENABLE_TAB_SCRUBBING_NAME" desc="Title for the flag to enable tab scrubbing.">
         Enable tab scrubbing
       </message>
-      <message name="IDS_FLAGS_ENABLE_TAB_SCRUBBING_DESCRIPTION" desc="Title for the flag to enable advanced gestures.">
-        Enables tab switching via 3 finger scroll.
+      <message name="IDS_FLAGS_ENABLE_TAB_SCRUBBING_DESCRIPTION" desc="Description for the flag to enable tab scrubbing.">
+        Enables tab switching via 3 finger horizontal scroll.
+      </message>
+      <message name="IDS_FLAGS_ENABLE_WORKSPACE_SCRUBBING_NAME" desc="Title for the flag to enable workspace scrubbing.">
+        Enable workspace scrubbing
+      </message>
+      <message name="IDS_FLAGS_ENABLE_WORKSPACE_SCRUBBING_DESCRIPTION" desc="Description for the flag to enable workspace scrubbing.">
+        Enables workspace switching via 3 finger vertical scroll.
       </message>
       <message name="IDS_FLAGS_ENABLE_IMMERSIVE_MODE_NAME" desc="Title for the flag to enable immersive mode.">
         Enable immersive windows

chrome/browser/about_flags.cc

@@ -1028,6 +1028,12 @@ const Experiment kExperiments[] = {
     kOsCrOS,
     SINGLE_VALUE_TYPE(switches::kAshEnableTabScrubbing),
   },
+  { "ash-enable-workspace-scrubbing",
+    IDS_FLAGS_ENABLE_WORKSPACE_SCRUBBING_NAME,
+    IDS_FLAGS_ENABLE_WORKSPACE_SCRUBBING_DESCRIPTION,
+    kOsCrOS,
+    SINGLE_VALUE_TYPE(ash::switches::kAshEnableWorkspaceScrubbing),
+  },
   { "ash-enable-immersive-mode",
     IDS_FLAGS_ENABLE_IMMERSIVE_MODE_NAME,
     IDS_FLAGS_ENABLE_IMMERSIVE_MODE_DESCRIPTION,