mouse_cursor_event_filter.cc revision 5d1f7b1de12d16ceb2c938c56701a3e8bfa558f7 
1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "ash/display/mouse_cursor_event_filter.h"
6
7#include "ash/display/cursor_window_controller.h"
8#include "ash/display/display_controller.h"
9#include "ash/display/display_manager.h"
10#include "ash/display/shared_display_edge_indicator.h"
11#include "ash/screen_util.h"
12#include "ash/shell.h"
13#include "ash/wm/coordinate_conversion.h"
14#include "ash/wm/window_util.h"
15#include "ui/aura/env.h"
16#include "ui/aura/root_window.h"
17#include "ui/aura/window.h"
18#include "ui/base/layout.h"
19#include "ui/compositor/dip_util.h"
20#include "ui/events/event.h"
21#include "ui/gfx/screen.h"
22
23namespace ash {
24namespace internal {
25namespace {
26
27// Maximum size on the display edge that initiate snapping phantom window,
28// from the corner of the display.
29const int kMaximumSnapHeight = 16;
30
31// Minimum height of an indicator on the display edge that allows
32// dragging a window.  If two displays shares the edge smaller than
33// this, entire edge will be used as a draggable space.
34const int kMinimumIndicatorHeight = 200;
35
36const int kIndicatorThickness = 1;
37}
38
39MouseCursorEventFilter::MouseCursorEventFilter()
40    : mouse_warp_mode_(WARP_ALWAYS),
41      was_mouse_warped_(false),
42      drag_source_root_(NULL),
43      scale_when_drag_started_(1.0f),
44      shared_display_edge_indicator_(new SharedDisplayEdgeIndicator) {
45}
46
47MouseCursorEventFilter::~MouseCursorEventFilter() {
48  HideSharedEdgeIndicator();
49}
50
51void MouseCursorEventFilter::ShowSharedEdgeIndicator(
52    const aura::Window* from) {
53  HideSharedEdgeIndicator();
54  if (Shell::GetScreen()->GetNumDisplays() <= 1 || from == NULL) {
55    src_indicator_bounds_.SetRect(0, 0, 0, 0);
56    dst_indicator_bounds_.SetRect(0, 0, 0, 0);
57    drag_source_root_ = NULL;
58    return;
59  }
60  drag_source_root_ = from;
61
62  DisplayLayout::Position position = Shell::GetInstance()->
63      display_manager()->GetCurrentDisplayLayout().position;
64  if (position == DisplayLayout::TOP || position == DisplayLayout::BOTTOM)
65    UpdateHorizontalIndicatorWindowBounds();
66  else
67    UpdateVerticalIndicatorWindowBounds();
68
69  shared_display_edge_indicator_->Show(src_indicator_bounds_,
70                                       dst_indicator_bounds_);
71}
72
73void MouseCursorEventFilter::HideSharedEdgeIndicator() {
74  shared_display_edge_indicator_->Hide();
75}
76
77void MouseCursorEventFilter::OnMouseEvent(ui::MouseEvent* event) {
78  if (event->type() == ui::ET_MOUSE_PRESSED) {
79    aura::Window* target = static_cast<aura::Window*>(event->target());
80    scale_when_drag_started_ = ui::GetDeviceScaleFactor(target->layer());
81  } else if (event->type() == ui::ET_MOUSE_RELEASED) {
82    scale_when_drag_started_ = 1.0f;
83  }
84
85  // Handle both MOVED and DRAGGED events here because when the mouse pointer
86  // enters the other root window while dragging, the underlying window system
87  // (at least X11) stops generating a ui::ET_MOUSE_MOVED event.
88  if (event->type() != ui::ET_MOUSE_MOVED &&
89      event->type() != ui::ET_MOUSE_DRAGGED) {
90      return;
91  }
92
93  if (!(event->flags() & ui::EF_IS_SYNTHESIZED)) {
94    Shell::GetInstance()->display_controller()->
95        cursor_window_controller()->UpdateLocation();
96  }
97
98  gfx::Point point_in_screen(event->location());
99  aura::Window* target = static_cast<aura::Window*>(event->target());
100  wm::ConvertPointToScreen(target, &point_in_screen);
101  if (WarpMouseCursorIfNecessary(target->GetRootWindow(), point_in_screen))
102    event->StopPropagation();
103}
104
105bool MouseCursorEventFilter::WarpMouseCursorIfNecessary(
106    aura::Window* target_root,
107    const gfx::Point& point_in_screen) {
108  if (Shell::GetScreen()->GetNumDisplays() <= 1 ||
109      mouse_warp_mode_ == WARP_NONE)
110    return false;
111
112  // Do not warp again right after the cursor was warped. Sometimes the offset
113  // is not long enough and the cursor moves at the edge of the destination
114  // display. See crbug.com/278885
115  // TODO(mukai): simplify the offset calculation below, it would not be
116  // necessary anymore with this flag.
117  if (was_mouse_warped_) {
118    was_mouse_warped_ = false;
119    return false;
120  }
121
122  aura::Window* root_at_point = wm::GetRootWindowAt(point_in_screen);
123  gfx::Point point_in_root = point_in_screen;
124  wm::ConvertPointFromScreen(root_at_point, &point_in_root);
125  gfx::Rect root_bounds = root_at_point->bounds();
126  int offset_x = 0;
127  int offset_y = 0;
128
129  // If the window is dragged between 2x display and 1x display,
130  // staring from 2x display, pointer location is rounded by the
131  // source scale factor (2x) so it will never reach the edge (which
132  // is odd). Shrink by scale factor of the display where the dragging
133  // started instead.  Only integral scale factor is supported for now.
134  int shrink = scale_when_drag_started_;
135  // Make the bounds inclusive to detect the edge.
136  root_bounds.Inset(0, 0, shrink, shrink);
137  gfx::Rect src_indicator_bounds = src_indicator_bounds_;
138  src_indicator_bounds.Inset(-shrink, -shrink, -shrink, -shrink);
139
140  if (point_in_root.x() <= root_bounds.x()) {
141    // Use -2, not -1, to avoid infinite loop of pointer warp.
142    offset_x = -2 * scale_when_drag_started_;
143  } else if (point_in_root.x() >= root_bounds.right()) {
144    offset_x = 2 * scale_when_drag_started_;
145  } else if (point_in_root.y() <= root_bounds.y()) {
146    offset_y = -2 * scale_when_drag_started_;
147  } else if (point_in_root.y() >= root_bounds.bottom()) {
148    offset_y = 2 * scale_when_drag_started_;
149  } else {
150    return false;
151  }
152
153  gfx::Point point_in_dst_screen(point_in_screen);
154  point_in_dst_screen.Offset(offset_x, offset_y);
155  aura::Window* dst_root = wm::GetRootWindowAt(point_in_dst_screen);
156
157  // Warp the mouse cursor only if the location is in the indicator bounds
158  // or the mouse pointer is in the destination root.
159  if (mouse_warp_mode_ == WARP_DRAG &&
160      dst_root != drag_source_root_ &&
161      !src_indicator_bounds.Contains(point_in_screen)) {
162    return false;
163  }
164
165  wm::ConvertPointFromScreen(dst_root, &point_in_dst_screen);
166
167  if (dst_root->bounds().Contains(point_in_dst_screen)) {
168    DCHECK_NE(dst_root, root_at_point);
169    was_mouse_warped_ = true;
170    dst_root->MoveCursorTo(point_in_dst_screen);
171    return true;
172  }
173  return false;
174}
175
176void MouseCursorEventFilter::UpdateHorizontalIndicatorWindowBounds() {
177  bool from_primary = Shell::GetPrimaryRootWindow() == drag_source_root_;
178  // GetPrimaryDisplay returns an object on stack, so copy the bounds
179  // instead of using reference.
180  const gfx::Rect primary_bounds =
181      Shell::GetScreen()->GetPrimaryDisplay().bounds();
182  const gfx::Rect secondary_bounds = ScreenUtil::GetSecondaryDisplay().bounds();
183  DisplayLayout::Position position = Shell::GetInstance()->
184      display_manager()->GetCurrentDisplayLayout().position;
185
186  src_indicator_bounds_.set_x(
187      std::max(primary_bounds.x(), secondary_bounds.x()));
188  src_indicator_bounds_.set_width(
189      std::min(primary_bounds.right(), secondary_bounds.right()) -
190      src_indicator_bounds_.x());
191  src_indicator_bounds_.set_height(kIndicatorThickness);
192  src_indicator_bounds_.set_y(
193      position == DisplayLayout::TOP ?
194      primary_bounds.y() - (from_primary ? 0 : kIndicatorThickness) :
195      primary_bounds.bottom() - (from_primary ? kIndicatorThickness : 0));
196
197  dst_indicator_bounds_ = src_indicator_bounds_;
198  dst_indicator_bounds_.set_height(kIndicatorThickness);
199  dst_indicator_bounds_.set_y(
200      position == DisplayLayout::TOP ?
201      primary_bounds.y() - (from_primary ? kIndicatorThickness : 0) :
202      primary_bounds.bottom() - (from_primary ? 0 : kIndicatorThickness));
203}
204
205void MouseCursorEventFilter::UpdateVerticalIndicatorWindowBounds() {
206  bool in_primary = Shell::GetPrimaryRootWindow() == drag_source_root_;
207  // GetPrimaryDisplay returns an object on stack, so copy the bounds
208  // instead of using reference.
209  const gfx::Rect primary_bounds =
210      Shell::GetScreen()->GetPrimaryDisplay().bounds();
211  const gfx::Rect secondary_bounds = ScreenUtil::GetSecondaryDisplay().bounds();
212  DisplayLayout::Position position = Shell::GetInstance()->
213      display_manager()->GetCurrentDisplayLayout().position;
214
215  int upper_shared_y = std::max(primary_bounds.y(), secondary_bounds.y());
216  int lower_shared_y = std::min(primary_bounds.bottom(),
217                                secondary_bounds.bottom());
218  int shared_height = lower_shared_y - upper_shared_y;
219
220  int dst_x = position == DisplayLayout::LEFT ?
221      primary_bounds.x() - (in_primary ? kIndicatorThickness : 0) :
222      primary_bounds.right() - (in_primary ? 0 : kIndicatorThickness);
223  dst_indicator_bounds_.SetRect(
224      dst_x, upper_shared_y, kIndicatorThickness, shared_height);
225
226  // The indicator on the source display.
227  src_indicator_bounds_.set_width(kIndicatorThickness);
228  src_indicator_bounds_.set_x(
229      position == DisplayLayout::LEFT ?
230      primary_bounds.x() - (in_primary ? 0 : kIndicatorThickness) :
231      primary_bounds.right() - (in_primary ? kIndicatorThickness : 0));
232
233  const gfx::Rect& source_bounds =
234      in_primary ? primary_bounds : secondary_bounds;
235  int upper_indicator_y = source_bounds.y() + kMaximumSnapHeight;
236  int lower_indicator_y = std::min(source_bounds.bottom(), lower_shared_y);
237
238  // This gives a hight that can be used without sacrifying the snap space.
239  int available_space = lower_indicator_y -
240      std::max(upper_shared_y, upper_indicator_y);
241
242  if (shared_height < kMinimumIndicatorHeight) {
243    // If the shared height is smaller than minimum height, use the
244    // entire height.
245    upper_indicator_y = upper_shared_y;
246  } else if (available_space < kMinimumIndicatorHeight) {
247    // Snap to the bottom.
248    upper_indicator_y =
249        std::max(upper_shared_y, lower_indicator_y + kMinimumIndicatorHeight);
250  } else {
251    upper_indicator_y = std::max(upper_indicator_y, upper_shared_y);
252  }
253  src_indicator_bounds_.set_y(upper_indicator_y);
254  src_indicator_bounds_.set_height(lower_indicator_y - upper_indicator_y);
255}
256
257}  // namespace internal
258}  // namespace ash
259