Windows docking should get triggered by pressing against the screen edge

ash/wm/dock/docked_window_layout_manager.cc

Index: ash/wm/dock/docked_window_layout_manager.cc
diff --git a/ash/wm/dock/docked_window_layout_manager.cc b/ash/wm/dock/docked_window_layout_manager.cc
index 36998df309179e3113ec83e016e32ce7f570c16a..81bab074e0b203574abd50097294e8fcbc3b218e 100644
--- a/ash/wm/dock/docked_window_layout_manager.cc
+++ b/ash/wm/dock/docked_window_layout_manager.cc
@@ -28,8 +28,9 @@ namespace internal {
 
 // Minimum, maximum width of the dock area and a width of the gap
 const int DockedWindowLayoutManager::kMinDockWidth = 200;
-const int DockedWindowLayoutManager::kMaxDockWidth = 450;
+const int DockedWindowLayoutManager::kMaxDockWidth = 360;
 const int DockedWindowLayoutManager::kMinDockGap = 2;
+const int kMaxVerticalPercentage = 90;

[flackr, 2013/09/06 02:18:43]

Just to simplify this CL, adding the max vertical percentage seems like a
tangential change that could be done as a separate CL.

[varkha, 2013/09/09 15:38:42]

Done.

 const int kWindowIdealSpacing = 4;
 
 namespace {
@@ -193,6 +194,7 @@ void DockedWindowLayoutManager::StartDragging(aura::Window* window) {
   dragged_window_ = window;
   // Start observing a window unless it is docked container's child in which
   // case it is already observed.
+  LOG(INFO) << "start dragging " << window;
   if (dragged_window_->parent() != dock_container_)
     dragged_window_->AddObserver(this);
   is_dragged_from_dock_ = window->parent() == dock_container_;
@@ -207,6 +209,7 @@ void DockedWindowLayoutManager::DockDraggedWindow(aura::Window* window) {
 void DockedWindowLayoutManager::UndockDraggedWindow() {
   OnWindowUndocked();
   Relayout();
+  UpdateDockBounds();
   is_dragged_from_dock_ = false;
 }
 
@@ -215,11 +218,16 @@ void DockedWindowLayoutManager::FinishDragging() {
   if (is_dragged_window_docked_)
     OnWindowUndocked();
   DCHECK (!is_dragged_window_docked_);
+  LOG(INFO) << "finish dragging " << dragged_window_;
   // Stop observing a window unless it is docked container's child in which
   // case it needs to keep being observed after the drag completes.
-  if (dragged_window_->parent() != dock_container_)
+  if (dragged_window_->parent() != dock_container_) {
     dragged_window_->RemoveObserver(this);
+    if (last_active_window_ == dragged_window_)
+      last_active_window_ = NULL;
+  }
   dragged_window_ = NULL;
+  dragged_bounds_ = gfx::Rect();
   Relayout();
   UpdateDockBounds();
 }
@@ -239,26 +247,20 @@ void DockedWindowLayoutManager::SetLauncher(ash::Launcher* launcher) {
 DockedAlignment DockedWindowLayoutManager::GetAlignmentOfWindow(
     const aura::Window* window) const {
   const gfx::Rect& bounds(window->GetBoundsInScreen());
-  const gfx::Rect docked_bounds = dock_container_->GetBoundsInScreen();
-
-  // Do not allow docking if a window is vertically maximized (as is the case
-  // when it is snapped).
-  const gfx::Rect work_area =
-      Shell::GetScreen()->GetDisplayNearestWindow(dock_container_).work_area();
-  if (bounds.y() == work_area.y() && bounds.height() == work_area.height())
-    return DOCKED_ALIGNMENT_NONE;
 
-  // Do not allow docking on the same side as launcher shelf.
-  ShelfAlignment shelf_alignment = SHELF_ALIGNMENT_BOTTOM;
-  if (launcher_)
-    shelf_alignment = launcher_->alignment();
+  // Test overlap with an existing docked area first.
+  if (docked_bounds_.Intersects(bounds) &&
+      alignment_ != DOCKED_ALIGNMENT_NONE) {
+    // A window is being added to other docked windows (on the same side).
+    return alignment_;
+  }
 
-  if (bounds.x() == docked_bounds.x() &&
-      shelf_alignment != SHELF_ALIGNMENT_LEFT) {
+  const gfx::Rect container_bounds = dock_container_->GetBoundsInScreen();
+  if (bounds.x() <= container_bounds.x() &&
+      bounds.right() > container_bounds.x()) {
     return DOCKED_ALIGNMENT_LEFT;
-  }
-  if (bounds.right() == docked_bounds.right() &&
-      shelf_alignment != SHELF_ALIGNMENT_RIGHT) {
+  } else if (bounds.x() < container_bounds.right() &&
+             bounds.right() >= container_bounds.right()) {
     return DOCKED_ALIGNMENT_RIGHT;
   }
   return DOCKED_ALIGNMENT_NONE;
@@ -293,6 +295,7 @@ void DockedWindowLayoutManager::OnWindowResized() {
 void DockedWindowLayoutManager::OnWindowAddedToLayout(aura::Window* child) {
   if (child->type() == aura::client::WINDOW_TYPE_POPUP)
     return;
+  LOG(INFO) << "added " << child;
   // Dragged windows are already observed by StartDragging and do not change
   // docked alignment during the drag.
   if (child == dragged_window_)
@@ -310,6 +313,7 @@ void DockedWindowLayoutManager::OnWindowAddedToLayout(aura::Window* child) {
 void DockedWindowLayoutManager::OnWindowRemovedFromLayout(aura::Window* child) {
   if (child->type() == aura::client::WINDOW_TYPE_POPUP)
     return;
+  LOG(INFO) << "removed " << child;
   // Dragged windows are stopped being observed by FinishDragging and do not
   // change alignment during the drag. They also cannot be set to be the
   // |last_active_window_|.
@@ -400,6 +404,7 @@ void DockedWindowLayoutManager::OnWindowBoundsChanged(
 }
 
 void DockedWindowLayoutManager::OnWindowDestroying(aura::Window* window) {
+  LOG(INFO) << "destroying " << window;
   if (dragged_window_ == window) {
     FinishDragging();
     DCHECK(!dragged_window_);
@@ -475,6 +480,7 @@ void DockedWindowLayoutManager::RestoreWindow(aura::Window* window) {
 }
 
 void DockedWindowLayoutManager::OnWindowDocked(aura::Window* window) {
+  LOG(INFO) << "docked";
   DCHECK(!is_dragged_window_docked_);
   is_dragged_window_docked_ = true;
 
@@ -484,6 +490,7 @@ void DockedWindowLayoutManager::OnWindowDocked(aura::Window* window) {
 }
 
 void DockedWindowLayoutManager::OnWindowUndocked() {
+  LOG(INFO) << "undocked";
   // If this is the first window getting docked - update alignment.
   if (!IsAnyWindowDocked())
     alignment_ = GetAlignmentOfWindow(dragged_window_);
@@ -544,7 +551,10 @@ void DockedWindowLayoutManager::Relayout() {
   int available_room = work_area.height();
   for (aura::Window::Windows::const_iterator iter = visible_windows.begin();
       iter != visible_windows.end(); ++iter) {
-    available_room -= (*iter)->bounds().height();
+    int height = (*iter)->bounds().height();
+    if (height == work_area.height())

[flackr, 2013/09/06 02:18:43]

This allows the height to be greater than kMaxVerticalPercentage as long as it's
less than work_area.height(). Setting height to min of the percentage and height
would be cleaner.

[varkha, 2013/09/09 15:38:42]

This was intentional to target vertically maximized windows rather than just
tall windows. I wanted to preserve vertical size when resized by a user but make
docking more friendly for the tiled windows. I am taking this part out as part
of vertical size split / minimizing.

+      height = work_area.height() * kMaxVerticalPercentage / 100;
+    available_room -= height;
   }
   const int num_windows = visible_windows.size();
   const float delta = (float)available_room /
@@ -564,6 +574,20 @@ void DockedWindowLayoutManager::Relayout() {
     aura::Window* window = *iter;
     gfx::Rect bounds = window->GetBoundsInScreen();
 
+    DockedAlignment alignment = alignment_;
+    if (alignment == DOCKED_ALIGNMENT_NONE && window == dragged_window_) {
+      alignment = GetAlignmentOfWindow(window);
+      if (alignment == DOCKED_ALIGNMENT_NONE)
+        bounds.set_size(gfx::Size());
+    }
+
+    // Restrict width.
+    if (bounds.width() > kMaxDockWidth)
+      bounds.set_width(kMaxDockWidth);
+    // Shrink height of vertically maximized windows to kMaxVerticalPercentage.
+    if (bounds.height() == work_area.height())
+      bounds.set_height(work_area.height() * kMaxVerticalPercentage / 100);
+
     // Fan out windows evenly distributing the overlap or remaining free space.
     bounds.set_y(std::max(work_area.y(),
                           std::min(work_area.bottom() - bounds.height(),
@@ -572,7 +596,7 @@ void DockedWindowLayoutManager::Relayout() {
 
     // All docked windows other than the one currently dragged remain stuck
     // to the screen edge.
-    switch (alignment_) {
+    switch (alignment) {
       case DOCKED_ALIGNMENT_LEFT:
         bounds.set_x(dock_bounds.x());
         break;
@@ -586,6 +610,8 @@ void DockedWindowLayoutManager::Relayout() {
       dragged_bounds_ = bounds;
       continue;
     }
+    // If the following asserts it is probably because not all the children
+    // have been removed when dock was closed.
     DCHECK_NE(alignment_, DOCKED_ALIGNMENT_NONE);
     // Keep the dock at least kMinDockWidth when all windows in it overhang.
     docked_width_ = std::min(kMaxDockWidth,