Moves window dragging/resizing logic into standalone class. I've got

some more cleanup to do in WorkspaceEventFilter, but I'll do that
separately.

BUG=111285
TEST=none
R=ben@chromium.org

Review URL: https://chromiumcodereview.appspot.com/9368057

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@122043 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 336 insertions, 0 deletions

diff --git a/ash/wm/window_resizer.cc b/ash/wm/window_resizer.cc
new file mode 100644
index 0000000..3953fb9
--- /dev/null
+++ b/ash/wm/window_resizer.cc
@@ -0,0 +1,336 @@
+// 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/window_resizer.h"
+
+#include "ui/aura/client/aura_constants.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/compositor/scoped_layer_animation_settings.h"
+#include "ui/gfx/screen.h"
+
+namespace ash {
+
+namespace {
+
+int GetPositionChangeDirectionForWindowComponent(int window_component) {
+  int pos_change_direction = WindowResizer::kBoundsChangeDirection_None;
+  switch (window_component) {
+    case HTTOPLEFT:
+    case HTBOTTOMRIGHT:
+    case HTGROWBOX:
+    case HTCAPTION:
+      pos_change_direction |=
+          WindowResizer::kBoundsChangeDirection_Horizontal |
+          WindowResizer::kBoundsChangeDirection_Vertical;
+      break;
+    case HTTOP:
+    case HTTOPRIGHT:
+    case HTBOTTOM:
+      pos_change_direction |= WindowResizer::kBoundsChangeDirection_Vertical;
+      break;
+    case HTBOTTOMLEFT:
+    case HTRIGHT:
+    case HTLEFT:
+      pos_change_direction |= WindowResizer::kBoundsChangeDirection_Horizontal;
+      break;
+    default:
+      break;
+  }
+  return pos_change_direction;
+}
+
+int GetSizeChangeDirectionForWindowComponent(int window_component) {
+  int size_change_direction = WindowResizer::kBoundsChangeDirection_None;
+  switch (window_component) {
+    case HTTOPLEFT:
+    case HTTOPRIGHT:
+    case HTBOTTOMLEFT:
+    case HTBOTTOMRIGHT:
+    case HTGROWBOX:
+    case HTCAPTION:
+      size_change_direction |=
+          WindowResizer::kBoundsChangeDirection_Horizontal |
+          WindowResizer::kBoundsChangeDirection_Vertical;
+      break;
+    case HTTOP:
+    case HTBOTTOM:
+      size_change_direction |= WindowResizer::kBoundsChangeDirection_Vertical;
+      break;
+    case HTRIGHT:
+    case HTLEFT:
+      size_change_direction |= WindowResizer::kBoundsChangeDirection_Horizontal;
+      break;
+    default:
+      break;
+  }
+  return size_change_direction;
+}
+
+// Returns true for resize components along the right edge, where a drag in
+// positive x will make the window larger.
+bool IsRightEdge(int window_component) {
+  return window_component == HTTOPRIGHT ||
+      window_component == HTRIGHT ||
+      window_component == HTBOTTOMRIGHT ||
+      window_component == HTGROWBOX;
+}
+
+// Returns true for resize components in along the bottom edge, where a drag
+// in positive y will make the window larger.
+bool IsBottomEdge(int window_component) {
+  return window_component == HTBOTTOMLEFT ||
+      window_component == HTBOTTOM ||
+      window_component == HTBOTTOMRIGHT ||
+      window_component == HTGROWBOX;
+}
+
+// Returns the closest location to |location| that is aligned to fall on
+// increments of |grid_size|.
+int AlignToGridRoundUp(int location, int grid_size) {
+  if (grid_size <= 1 || location % grid_size == 0)
+    return location;
+  return (location / grid_size + 1) * grid_size;
+}
+
+gfx::Point ConvertPointToParent(aura::Window* window,
+                                const gfx::Point& point) {
+  gfx::Point result(point);
+  aura::Window::ConvertPointToWindow(window, window->parent(), &result);
+  return result;
+}
+
+bool IsNormalWindow(aura::Window* window) {
+  return window->GetProperty(aura::client::kShowStateKey) ==
+          ui::SHOW_STATE_NORMAL ||
+      window->GetProperty(aura::client::kShowStateKey) ==
+          ui::SHOW_STATE_DEFAULT;
+}
+
+}  // namespace
+
+// static
+const int WindowResizer::kBoundsChange_None = 0;
+// static
+const int WindowResizer::kBoundsChange_Repositions = 1;
+// static
+const int WindowResizer::kBoundsChange_Resizes = 2;
+
+// static
+const int WindowResizer::kBoundsChangeDirection_None = 0;
+// static
+const int WindowResizer::kBoundsChangeDirection_Horizontal = 1;
+// static
+const int WindowResizer::kBoundsChangeDirection_Vertical = 2;
+
+WindowResizer::WindowResizer(aura::Window* window,
+                             const gfx::Point& location,
+                             int window_component,
+                             int grid_size)
+    : window_(window),
+      initial_bounds_(window->bounds()),
+      initial_location_in_parent_(ConvertPointToParent(window, location)),
+      window_component_(window_component),
+      bounds_change_(GetBoundsChangeForWindowComponent(window_component_)),
+      position_change_direction_(
+          GetPositionChangeDirectionForWindowComponent(window_component_)),
+      size_change_direction_(
+          GetSizeChangeDirectionForWindowComponent(window_component_)),
+      is_resizable_(bounds_change_ != kBoundsChangeDirection_None &&
+                    IsNormalWindow(window)),
+      grid_size_(grid_size),
+      did_move_or_resize_(false) {
+}
+
+WindowResizer::~WindowResizer() {
+}
+
+// static
+int WindowResizer::GetBoundsChangeForWindowComponent(int component) {
+  int bounds_change = WindowResizer::kBoundsChange_None;
+  switch (component) {
+    case HTTOPLEFT:
+    case HTTOP:
+    case HTTOPRIGHT:
+    case HTLEFT:
+    case HTBOTTOMLEFT:
+      bounds_change |= WindowResizer::kBoundsChange_Repositions |
+                      WindowResizer::kBoundsChange_Resizes;
+      break;
+    case HTCAPTION:
+      bounds_change |= WindowResizer::kBoundsChange_Repositions;
+      break;
+    case HTRIGHT:
+    case HTBOTTOMRIGHT:
+    case HTBOTTOM:
+    case HTGROWBOX:
+      bounds_change |= WindowResizer::kBoundsChange_Resizes;
+      break;
+    default:
+      break;
+  }
+  return bounds_change;
+}
+
+// static
+int WindowResizer::AlignToGrid(int location, int grid_size) {
+  if (grid_size <= 1 || location % grid_size == 0)
+    return location;
+  return floor(static_cast<float>(location) / static_cast<float>(grid_size) +
+               .5f) * grid_size;
+}
+
+void WindowResizer::Drag(const gfx::Point& location) {
+  gfx::Rect bounds = GetBoundsForDrag(location);
+  if (bounds != window_->bounds()) {
+    did_move_or_resize_ = true;
+    window_->SetBounds(bounds);
+  }
+}
+
+void WindowResizer::CompleteDrag() {
+  if (grid_size_ <= 1 || !did_move_or_resize_)
+    return;
+  const gfx::Rect& bounds(window_->bounds());
+  int x = AlignToGrid(bounds.x(), grid_size_);
+  int y = AlignToGrid(bounds.y(), grid_size_);
+  gfx::Rect new_bounds(x, y, bounds.width(), bounds.height());
+  if (new_bounds == window_->bounds())
+    return;
+
+  ui::ScopedLayerAnimationSettings scoped_setter(
+      window_->layer()->GetAnimator());
+  // Use a small duration since the grid is small.
+  scoped_setter.SetTransitionDuration(base::TimeDelta::FromMilliseconds(100));
+  window_->SetBounds(new_bounds);
+}
+
+gfx::Rect WindowResizer::GetBoundsForDrag(const gfx::Point& location) {
+  if (!is_resizable())
+    return window_->bounds();
+
+  // Dragging a window moves the local coordinate frame, so do arithmetic
+  // in the parent coordinate frame.
+  gfx::Point event_location_in_parent(location);
+  aura::Window::ConvertPointToWindow(window_, window_->parent(),
+                                     &event_location_in_parent);
+  int delta_x = event_location_in_parent.x() - initial_location_in_parent_.x();
+  int delta_y = event_location_in_parent.y() - initial_location_in_parent_.y();
+
+  // The minimize size constraint may limit how much we change the window
+  // position.  For example, dragging the left edge to the right should stop
+  // repositioning the window when the minimize size is reached.
+  gfx::Size size = GetSizeForDrag(&delta_x, &delta_y);
+  gfx::Point origin = GetOriginForDrag(delta_x, delta_y);
+
+  gfx::Rect new_bounds(origin, size);
+  // Update bottom edge to stay in the work area when we are resizing
+  // by dragging the bottome edge or corners.
+  if (bounds_change_ & kBoundsChange_Resizes &&
+      origin.y() == window_->bounds().y()) {
+    gfx::Rect work_area = gfx::Screen::GetMonitorWorkAreaNearestWindow(window_);
+    if (new_bounds.bottom() > work_area.bottom())
+      new_bounds.Inset(0, 0, 0,
+                       new_bounds.bottom() - work_area.bottom());
+  }
+  if (bounds_change_ & kBoundsChange_Resizes &&
+      bounds_change_ & kBoundsChange_Repositions && new_bounds.y() < 0) {
+    int delta = new_bounds.y();
+    new_bounds.set_y(0);
+    new_bounds.set_height(new_bounds.height() + delta);
+  }
+  return new_bounds;
+}
+
+gfx::Point WindowResizer::GetOriginForDrag(
+    int delta_x,
+    int delta_y) const {
+  gfx::Point origin = initial_bounds_.origin();
+  if (bounds_change_ & kBoundsChange_Repositions) {
+    int pos_change_direction =
+        GetPositionChangeDirectionForWindowComponent(window_component_);
+    if (pos_change_direction & kBoundsChangeDirection_Horizontal)
+      origin.Offset(delta_x, 0);
+    if (pos_change_direction & kBoundsChangeDirection_Vertical)
+      origin.Offset(0, delta_y);
+  }
+  return origin;
+}
+
+gfx::Size WindowResizer::GetSizeForDrag(
+    int* delta_x,
+    int* delta_y) const {
+  gfx::Size size = initial_bounds_.size();
+  if (bounds_change_ & kBoundsChange_Resizes) {
+    gfx::Size min_size = window_->delegate()->GetMinimumSize();
+    min_size.set_width(AlignToGridRoundUp(min_size.width(), grid_size_));
+    min_size.set_height(AlignToGridRoundUp(min_size.height(), grid_size_));
+    size.SetSize(GetWidthForDrag(min_size.width(), delta_x),
+                 GetHeightForDrag(min_size.height(), delta_y));
+  }
+  return size;
+}
+
+int WindowResizer::GetWidthForDrag(int min_width, int* delta_x) const {
+  int width = initial_bounds_.width();
+  if (size_change_direction_ & kBoundsChangeDirection_Horizontal) {
+    // Along the right edge, positive delta_x increases the window size.
+    int x_multiplier = IsRightEdge(window_component_) ? 1 : -1;
+    width += x_multiplier * (*delta_x);
+    int adjusted_width = AlignToGrid(width, grid_size_);
+    if (adjusted_width != width) {
+      *delta_x += -x_multiplier * (width - adjusted_width);
+      width = adjusted_width;
+    }
+
+    // Ensure we don't shrink past the minimum width and clamp delta_x
+    // for the window origin computation.
+    if (width < min_width) {
+      width = min_width;
+      *delta_x = -x_multiplier * (initial_bounds_.width() - min_width);
+    }
+
+    // And don't let the window go bigger than the monitor.
+    int max_width =
+        gfx::Screen::GetMonitorAreaNearestWindow(window_).width();
+    if (width > max_width) {
+      width = max_width;
+      *delta_x = -x_multiplier * (initial_bounds_.width() - max_width);
+    }
+  }
+  return width;
+}
+
+int WindowResizer::GetHeightForDrag(int min_height, int* delta_y) const {
+  int height = initial_bounds_.height();
+  if (size_change_direction_ & kBoundsChangeDirection_Vertical) {
+    // Along the bottom edge, positive delta_y increases the window size.
+    int y_multiplier = IsBottomEdge(window_component_) ? 1 : -1;
+    height += y_multiplier * (*delta_y);
+    int adjusted_height = AlignToGrid(height, grid_size_);
+    if (height != adjusted_height) {
+      *delta_y += -y_multiplier * (height - adjusted_height);
+      height = adjusted_height;
+    }
+
+    // Ensure we don't shrink past the minimum height and clamp delta_y
+    // for the window origin computation.
+    if (height < min_height) {
+      height = min_height;
+      *delta_y = -y_multiplier * (initial_bounds_.height() - min_height);
+    }
+
+    // And don't let the window go bigger than the monitor.
+    int max_height = gfx::Screen::GetMonitorAreaNearestWindow(window_).height();
+    if (height > max_height) {
+      height = max_height;
+      *delta_y = -y_multiplier * (initial_bounds_.height() - max_height);
+    }
+  }
+  return height;
+}
+
+}  // namespace aura