Minor refactoring of window resize code. I wasn't too happy with

ash/wm/window_resizer.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/window_resizer.h"
 
 #include "ash/shell.h"
 #include "ash/wm/root_window_event_filter.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/root_window.h"
@@ skipping 64 matching lines @@
 
 // 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;
-}
-
 }  // 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),
-      grid_size_(grid_size),
-      did_move_or_resize_(false),
-      root_filter_(NULL) {
-  if (is_resizable_) {
-    root_filter_ = Shell::GetInstance()->root_filter();
-    if (root_filter_)
-      root_filter_->LockCursor();
-  }
+WindowResizer::Details::Details()
+    : window(NULL),
+      window_component(HTNOWHERE),
+      bounds_change(0),
+      position_change_direction(0),
+      size_change_direction(0),
+      is_resizable(false),
+      grid_size(0) {
+}
+
+WindowResizer::Details::Details(aura::Window* window,
+                                const gfx::Point& location,
+                                int window_component,
+                                int grid_size)
+  : window(window),
+    initial_bounds(window->bounds()),
+    initial_location_in_parent(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),
+    grid_size(grid_size) {
+}
+
+WindowResizer::Details::~Details() {
+}
+
+WindowResizer::WindowResizer() {
 }
 
 WindowResizer::~WindowResizer() {
-  if (root_filter_)
-    root_filter_->UnlockCursor();
 }
 
 // static
 int WindowResizer::GetBoundsChangeForWindowComponent(int component) {
   int bounds_change = WindowResizer::kBoundsChange_None;
   switch (component) {
     case HTTOPLEFT:
     case HTTOP:
     case HTTOPRIGHT:
     case HTLEFT:
@@ skipping 17 matching lines @@
 }
 
 // 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);
-  }
-}
+// static
+gfx::Rect WindowResizer::CalculateBoundsForDrag(
+    const Details& details,
+    const gfx::Point& location) {
+  if (!details.is_resizable)
+    return details.initial_bounds;
 
-void WindowResizer::CompleteDrag() {
-  if (grid_size_ <= 1 || !did_move_or_resize_)
-    return;
-  gfx::Rect new_bounds(GetFinalBounds());
-  if (new_bounds == window_->bounds())
-    return;
-
-  if (new_bounds.size() != window_->bounds().size()) {
-    // Don't attempt to animate a size change.
-    window_->SetBounds(new_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);
-}
-
-void WindowResizer::RevertDrag() {
-  if (!did_move_or_resize_)
-    return;
-
-  window_->SetBounds(initial_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();
+  int delta_x = location.x() - details.initial_location_in_parent.x();
+  int delta_y = location.y() - details.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::Size size = GetSizeForDrag(details, &delta_x, &delta_y);
+  gfx::Point origin = GetOriginForDrag(details, 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 (details.bounds_change & kBoundsChange_Resizes &&
+      origin.y() == details.window->bounds().y()) {
+    gfx::Rect work_area = gfx::Screen::GetMonitorWorkAreaNearestWindow(
+        details.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) {
+  if (details.bounds_change & kBoundsChange_Resizes &&
+      details.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::Rect WindowResizer::GetFinalBounds() {
-  const gfx::Rect& bounds(window_->bounds());
-  int x = AlignToGrid(bounds.x(), grid_size_);
-  int y = AlignToGrid(bounds.y(), grid_size_);
+// static
+gfx::Rect WindowResizer::AdjustBoundsToGrid(const Details& details) {
+  const gfx::Rect& bounds(details.window->bounds());
+  if (details.grid_size <= 1)
+    return bounds;
+  int x = AlignToGrid(bounds.x(), details.grid_size);
+  int y = AlignToGrid(bounds.y(), details.grid_size);
   return gfx::Rect(x, y, bounds.width(), bounds.height());
 }
 
-gfx::Point WindowResizer::GetOriginForDrag(
-    int delta_x,
-    int delta_y) const {
-  gfx::Point origin = initial_bounds_.origin();
-  if (bounds_change_ & kBoundsChange_Repositions) {
+// static
+bool WindowResizer::IsBottomEdge(int window_component) {
+  return window_component == HTBOTTOMLEFT ||
+      window_component == HTBOTTOM ||
+      window_component == HTBOTTOMRIGHT ||
+      window_component == HTGROWBOX;
+}
+
+// static
+gfx::Point WindowResizer::GetOriginForDrag(const Details& details,
+                                           int delta_x,
+                                           int delta_y) {
+  gfx::Point origin = details.initial_bounds.origin();
+  if (details.bounds_change & kBoundsChange_Repositions) {
     int pos_change_direction =
-        GetPositionChangeDirectionForWindowComponent(window_component_);
+        GetPositionChangeDirectionForWindowComponent(details.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));
+// static
+gfx::Size WindowResizer::GetSizeForDrag(const Details& details,
+                                        int* delta_x,
+                                        int* delta_y) {
+  gfx::Size size = details.initial_bounds.size();
+  if (details.bounds_change & kBoundsChange_Resizes) {
+    gfx::Size min_size = details.window->delegate()->GetMinimumSize();
+    min_size.set_width(AlignToGridRoundUp(min_size.width(), details.grid_size));
+    min_size.set_height(AlignToGridRoundUp(min_size.height(),
+                                           details.grid_size));
+    size.SetSize(GetWidthForDrag(details, min_size.width(), delta_x),
+                 GetHeightForDrag(details, 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) {
+// static
+int WindowResizer::GetWidthForDrag(const Details& details,
+                                   int min_width,
+                                   int* delta_x) {
+  int width = details.initial_bounds.width();
+  if (details.size_change_direction & kBoundsChangeDirection_Horizontal) {
     // Along the right edge, positive delta_x increases the window size.
-    int x_multiplier = IsRightEdge(window_component_) ? 1 : -1;
+    int x_multiplier = IsRightEdge(details.window_component) ? 1 : -1;
     width += x_multiplier * (*delta_x);
-    int adjusted_width = AlignToGrid(width, grid_size_);
+    int adjusted_width = AlignToGrid(width, details.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);
+      *delta_x = -x_multiplier * (details.initial_bounds.width() - min_width);
     }
 
     // And don't let the window go bigger than the monitor.
     int max_width =
-        gfx::Screen::GetMonitorAreaNearestWindow(window_).width();
+        gfx::Screen::GetMonitorAreaNearestWindow(details.window).width();
     if (width > max_width) {
       width = max_width;
-      *delta_x = -x_multiplier * (initial_bounds_.width() - max_width);
+      *delta_x = -x_multiplier * (details.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) {
+// static
+int WindowResizer::GetHeightForDrag(const Details& details,
+                                    int min_height,
+                                    int* delta_y) {
+  int height = details.initial_bounds.height();
+  if (details.size_change_direction & kBoundsChangeDirection_Vertical) {
     // Along the bottom edge, positive delta_y increases the window size.
-    int y_multiplier = IsBottomEdge(window_component_) ? 1 : -1;
+    int y_multiplier = IsBottomEdge(details.window_component) ? 1 : -1;
     height += y_multiplier * (*delta_y);
-    int adjusted_height = AlignToGrid(height, grid_size_);
+    int adjusted_height = AlignToGrid(height, details.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);
+      *delta_y = -y_multiplier * (details.initial_bounds.height() - min_height);
     }
 
     // And don't let the window go bigger than the monitor.
-    int max_height = gfx::Screen::GetMonitorAreaNearestWindow(window_).height();
+    int max_height =
+        gfx::Screen::GetMonitorAreaNearestWindow(details.window).height();
     if (height > max_height) {
       height = max_height;
-      *delta_y = -y_multiplier * (initial_bounds_.height() - max_height);
+      *delta_y = -y_multiplier * (details.initial_bounds.height() - max_height);
     }
   }
   return height;
 }
 
 }  // namespace aura