Initial cut at multi-window resize code. There's still some TODOs, but

ash/wm/workspace/multi_window_resize_controller.cc

Index: ash/wm/workspace/multi_window_resize_controller.cc
diff --git a/ash/wm/workspace/multi_window_resize_controller.cc b/ash/wm/workspace/multi_window_resize_controller.cc
new file mode 100644
index 0000000000000000000000000000000000000000..c60a81812baaf4858518b791f381cf7928f8a95f
--- /dev/null
+++ b/ash/wm/workspace/multi_window_resize_controller.cc
@@ -0,0 +1,376 @@
+// 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/multi_window_resize_controller.h"
+
+#include "ash/shell.h"
+#include "ash/shell_window_ids.h"
+#include "ash/wm/root_window_event_filter.h"
+#include "ash/wm/workspace/workspace_event_filter.h"
+#include "ash/wm/workspace/workspace_window_resizer.h"
+#include "ui/aura/event_filter.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/gfx/canvas.h"
+#include "ui/gfx/canvas_skia.h"
+#include "ui/gfx/screen.h"
+#include "ui/views/view.h"
+#include "ui/views/widget/widget.h"
+#include "ui/views/widget/widget_delegate.h"
+
+using aura::Window;
+
+namespace ash {
+namespace internal {
+
+namespace {
+
+const int kShowDelayMS = 100;
+
+// Padding from the bottom/right edge the resize widget is shown at.
+const int kResizeWidgetPadding = 40;
+
+bool ContainsX(Window* window, int x) {
+  return window->bounds().x() <= x && window->bounds().right() >= x;
+}
+
+bool ContainsY(Window* window, int y) {
+  return window->bounds().y() <= y && window->bounds().bottom() >= y;
+}
+
+}  // namespace
+
+// View contained in the widget. Passes along mouse events to the
+// MultiWindowResizeController so that it can start/stop the resize loop.
+class MultiWindowResizeController::ResizeView : public views::View {
+ public:
+  explicit ResizeView(MultiWindowResizeController* controller,
+                      Direction direction)
+      : controller_(controller),
+        direction_(direction) {
+  }
+
+  // views::View overrides:
+  virtual gfx::Size GetPreferredSize() OVERRIDE {
+    return gfx::Size(30, 30);
+  }
+  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE {
+    // TODO: replace with real assets.
+    SkPaint paint;
+    paint.setColor(SkColorSetARGB(128, 0, 0, 0));
+    paint.setStyle(SkPaint::kFill_Style);
+    paint.setAntiAlias(true);
+    canvas->AsCanvasSkia()->GetSkCanvas()->drawCircle(
+        SkIntToScalar(15), SkIntToScalar(15), SkIntToScalar(15), paint);
+  }
+  virtual bool OnMousePressed(const views::MouseEvent& event) OVERRIDE {
+    gfx::Point location(event.location());
+    views::View::ConvertPointToScreen(this, &location);
+    controller_->StartResize(location);
+    return true;
+  }
+  virtual bool OnMouseDragged(const views::MouseEvent& event) OVERRIDE {
+    gfx::Point location(event.location());
+    views::View::ConvertPointToScreen(this, &location);
+    controller_->Resize(location);
+    return true;
+  }
+  virtual void OnMouseReleased(const views::MouseEvent& event) OVERRIDE {
+    controller_->CompleteResize();
+  }
+  virtual void OnMouseCaptureLost() OVERRIDE {
+    controller_->CancelResize();
+  }
+  virtual gfx::NativeCursor GetCursor(
+      const views::MouseEvent& event) OVERRIDE {
+    int component = (direction_ == LEFT_RIGHT) ? HTRIGHT : HTBOTTOM;
+    return RootWindowEventFilter::CursorForWindowComponent(component);
+  }
+
+ private:
+  MultiWindowResizeController* controller_;
+  const Direction direction_;
+
+  DISALLOW_COPY_AND_ASSIGN(ResizeView);
+};
+
+// MouseWatcherHost implementation for MultiWindowResizeController. Forwards
+// Contains() to MultiWindowResizeController.
+class MultiWindowResizeController::ResizeMouseWatcherHost :
+   public views::MouseWatcherHost {
+ public:
+  ResizeMouseWatcherHost(MultiWindowResizeController* host) : host_(host) {}
+
+  // MouseWatcherHost overrides:
+  virtual bool Contains(const gfx::Point& screen_point,
+                        MouseEventType type) OVERRIDE {
+    return !host_->IsOverWindows(screen_point);
+  }
+
+ private:
+  MultiWindowResizeController* host_;
+
+  DISALLOW_COPY_AND_ASSIGN(ResizeMouseWatcherHost);
+};
+
+MultiWindowResizeController::ResizeWindows::ResizeWindows()
+    : window1(NULL),
+      window2(NULL),
+      direction(TOP_BOTTOM){
+}
+
+MultiWindowResizeController::ResizeWindows::~ResizeWindows() {
+}
+
+bool MultiWindowResizeController::ResizeWindows::Equals(
+    const ResizeWindows& other) const {
+  return window1 == other.window1 &&
+      window2 == other.window2 &&
+      direction == other.direction;
+}
+
+MultiWindowResizeController::MultiWindowResizeController()
+    : resize_widget_(NULL),
+      grid_size_(0) {
+}
+
+MultiWindowResizeController::~MultiWindowResizeController() {
+  Hide();
+}
+
+void MultiWindowResizeController::Show(Window* window,
+                                       int component,
+                                       const gfx::Point& point) {
+  ResizeWindows windows(DetermineWindows(window, component, point));
+  if (IsShowing()) {
+    if (windows_.Equals(windows))
+      return;
+    Hide();
+    // Fall through to see if there is another hot spot we should show at.
+  }
+
+  windows_ = windows;
+  if (!windows_.is_valid())
+    return;
+  // TODO: need to listen for windows to be closed/destroyed, maybe window
+  // moved too.
+  show_timer_.Start(FROM_HERE,
+                    base::TimeDelta::FromMilliseconds(kShowDelayMS),
+                    this, &MultiWindowResizeController::ShowNow);
+}
+
+void MultiWindowResizeController::Hide() {
+  if (window_resizer_.get())
+    return;  // Ignore hides while actively resizing.
+
+  show_timer_.Stop();
+  if (!resize_widget_)
+    return;
+  resize_widget_->Close();
+  resize_widget_ = NULL;
+  windows_ = ResizeWindows();
+}
+
+void MultiWindowResizeController::MouseMovedOutOfHost() {
+  Hide();
+}
+
+MultiWindowResizeController::ResizeWindows
+MultiWindowResizeController::DetermineWindows(
+    Window* window,
+    int window_component,
+    const gfx::Point& point) const {
+  ResizeWindows result;
+  gfx::Point point_in_parent(point);
+  Window::ConvertPointToWindow(window, window->parent(), &point_in_parent);
+  switch (window_component) {
+    case HTRIGHT:
+      result.direction = LEFT_RIGHT;
+      result.window1 = window;
+      result.window2 = FindWindowByEdge(
+          window, HTLEFT, window->bounds().right(), point_in_parent.y());
+      break;
+    case HTLEFT:
+      result.direction = LEFT_RIGHT;
+      result.window1 = FindWindowByEdge(
+          window, HTRIGHT, window->bounds().x(), point_in_parent.y());
+      result.window2 = window;
+      break;
+    case HTTOP:
+      result.direction = TOP_BOTTOM;
+      result.window1 = FindWindowByEdge(
+          window, HTBOTTOM, point_in_parent.x(), window->bounds().y());
+      result.window2 = window;
+      break;
+    case HTBOTTOM:
+      result.direction = TOP_BOTTOM;
+      result.window1 = window;
+      result.window2 = FindWindowByEdge(
+          window, HTTOP, point_in_parent.x(), window->bounds().bottom());
+      break;
+    default:
+      break;
+  }
+  return result;
+}
+
+Window* MultiWindowResizeController::FindWindowByEdge(
+    Window* window_to_ignore,
+    int edge_want,
+    int x,
+    int y) const {
+  Window* parent = window_to_ignore->parent();
+  const Window::Windows& windows(parent->children());
+  for (Window::Windows::const_reverse_iterator i = windows.rbegin();
+       i != windows.rend(); ++i) {
+    Window* window = *i;
+    if (window == window_to_ignore || !window->IsVisible())
+      continue;
+    switch (edge_want) {
+      case HTLEFT:
+        if (ContainsY(window, y) && window->bounds().x() == x)
+          return window;
+        break;
+      case HTRIGHT:
+        if (ContainsY(window, y) && window->bounds().right() == x)
+          return window;
+        break;
+      case HTTOP:
+        if (ContainsX(window, x) && window->bounds().y() == y)
+          return window;
+        break;
+      case HTBOTTOM:
+        if (ContainsX(window, x) && window->bounds().bottom() == y)
+          return window;
+        break;
+      default:
+        NOTREACHED();
+    }
+    // Window doesn't contain the edge, but if window contains |point|
+    // it's obscuring any other window that could be at the location.
+    if (window->bounds().Contains(x, y))
+      return NULL;
+  }
+  return NULL;
+}
+
+void MultiWindowResizeController::ShowNow() {
+  DCHECK(!resize_widget_);
+  DCHECK(windows_.is_valid());
+  show_timer_.Stop();
+  resize_widget_ = new views::Widget;
+  views::Widget::InitParams params(views::Widget::InitParams::TYPE_POPUP);
+  params.transparent = true;
+  params.ownership = views::Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
+  params.parent = Shell::GetInstance()->GetContainer(
+      ash::internal::kShellWindowId_AlwaysOnTopContainer);
+  params.can_activate = false;
+  ResizeView* view = new ResizeView(this, windows_.direction);
+  params.delegate = new views::WidgetDelegateView;
+  resize_widget_->set_focus_on_creation(false);
+  resize_widget_->Init(params);
+  resize_widget_->GetNativeWindow()->SetName("MultiWindowResizeController");
+  resize_widget_->SetContentsView(view);
+  show_bounds_ = CalculateResizeWidgetBounds();
+  resize_widget_->SetBounds(show_bounds_);
+  resize_widget_->Show();
+}
+
+bool MultiWindowResizeController::IsShowing() const {
+  return resize_widget_ || show_timer_.IsRunning();
+}
+
+void MultiWindowResizeController::StartResize(
+    const gfx::Point& screen_location) {
+  DCHECK(!window_resizer_.get());
+  DCHECK(windows_.is_valid());
+  gfx::Point parent_location(screen_location);
+  aura::Window::ConvertPointToWindow(
+      windows_.window1->GetRootWindow(), windows_.window1->parent(),
+      &parent_location);
+  std::vector<aura::Window*> windows;
+  windows.push_back(windows_.window2);
+  // TODO: search for other windows.
+  int component = windows_.direction == LEFT_RIGHT ? HTRIGHT : HTBOTTOM;
+  window_resizer_.reset(WorkspaceWindowResizer::Create(
+      windows_.window1, parent_location, component, grid_size_, windows));
+}
+
+void MultiWindowResizeController::Resize(const gfx::Point& screen_location) {
+  gfx::Point parent_location(screen_location);
+  aura::Window::ConvertPointToWindow(windows_.window1->GetRootWindow(),
+                                     windows_.window1->parent(),
+                                     &parent_location);
+  window_resizer_->Drag(parent_location);
+  gfx::Rect bounds = CalculateResizeWidgetBounds();
+  if (windows_.direction == LEFT_RIGHT)
+    bounds.set_y(show_bounds_.y());
+  else
+    bounds.set_x(show_bounds_.x());
+  resize_widget_->SetBounds(bounds);
+}
+
+void MultiWindowResizeController::CompleteResize() {
+  window_resizer_->CompleteDrag();
+  window_resizer_.reset();
+
+  // Mouse may still be over resizer, if not hide.
+  gfx::Point screen_loc = gfx::Screen::GetCursorScreenPoint();
+  if (!resize_widget_->GetWindowScreenBounds().Contains(screen_loc))
+    Hide();
+}
+
+void MultiWindowResizeController::CancelResize() {
+  window_resizer_->RevertDrag();
+  window_resizer_.reset();
+  Hide();
+}
+
+gfx::Rect MultiWindowResizeController::CalculateResizeWidgetBounds() const {
+  gfx::Size pref = resize_widget_->GetContentsView()->GetPreferredSize();
+  int x = 0, y = 0;
+  if (windows_.direction == LEFT_RIGHT) {
+    x = windows_.window1->bounds().right() - pref.width() / 2;
+    y = std::min(windows_.window1->bounds().bottom(),
+                 windows_.window2->bounds().bottom()) - kResizeWidgetPadding;
+    y -= pref.height() / 2;
+  } else {
+    x = std::min(windows_.window1->bounds().right(),
+                 windows_.window2->bounds().right()) - kResizeWidgetPadding;
+    x -= pref.width() / 2;
+    y = windows_.window1->bounds().bottom() - pref.height() / 2;
+  }
+  return gfx::Rect(x, y, pref.width(), pref.height());
+}
+
+bool MultiWindowResizeController::IsOverWindows(
+    const gfx::Point& screen_location) const {
+  if (window_resizer_.get())
+    return true;  // Ignore hides while actively resizing.
+
+  if (resize_widget_->GetWindowScreenBounds().Contains(screen_location))
+    return true;
+
+  return IsOverWindow(windows_.window1, screen_location) ||
+      IsOverWindow(windows_.window2, screen_location);
+}
+
+bool MultiWindowResizeController::IsOverWindow(
+    aura::Window* window,
+    const gfx::Point& screen_location) const {
+  if (!window->GetScreenBounds().Contains(screen_location))
+    return false;
+
+  gfx::Point window_loc(screen_location);
+  aura::Window::ConvertPointToWindow(
+      window->GetRootWindow(), window->parent(), &window_loc);
+  int component = window->delegate()->GetNonClientComponent(window_loc);
+  // TODO: this needs to make sure no other window is obscuring window.
+  return windows_.Equals(DetermineWindows(window, component, window_loc));
+}
+
+}  // namespace internal
+}  // namespace ash