partial_magnification_controller.cc revision f2477e01787aa58f445919b809d89e252beef54f 
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/magnifier/partial_magnification_controller.h"
6
7#include "ash/shell.h"
8#include "ash/shell_window_ids.h"
9#include "ui/aura/root_window.h"
10#include "ui/views/corewm/compound_event_filter.h"
11#include "ui/aura/window.h"
12#include "ui/aura/window_property.h"
13#include "ui/gfx/screen.h"
14#include "ui/compositor/layer.h"
15#include "ui/views/layout/fill_layout.h"
16#include "ui/views/widget/widget.h"
17#include "ui/views/widget/widget_delegate.h"
18
19namespace {
20
21const float kMinPartialMagnifiedScaleThreshold = 1.1f;
22
23// Number of pixels to make the border of the magnified area.
24const int kZoomInset = 16;
25
26// Width of the magnified area.
27const int kMagnifierWidth = 200;
28
29// Height of the magnified area.
30const int kMagnifierHeight = 200;
31
32// Name of the magnifier window.
33const char kPartialMagniferWindowName[] = "PartialMagnifierWindow";
34
35}  // namespace
36
37namespace ash {
38
39PartialMagnificationController::PartialMagnificationController()
40    : is_on_zooming_(false),
41      is_enabled_(false),
42      scale_(kNonPartialMagnifiedScale),
43      zoom_widget_(NULL) {
44  Shell::GetInstance()->AddPreTargetHandler(this);
45}
46
47PartialMagnificationController::~PartialMagnificationController() {
48  CloseMagnifierWindow();
49
50  Shell::GetInstance()->RemovePreTargetHandler(this);
51}
52
53void PartialMagnificationController::SetScale(float scale) {
54  if (!is_enabled_)
55    return;
56
57  scale_ = scale;
58
59  if (IsPartialMagnified()) {
60    CreateMagnifierWindow();
61  } else {
62    CloseMagnifierWindow();
63  }
64}
65
66void PartialMagnificationController::SetEnabled(bool enabled) {
67  if (enabled) {
68    is_enabled_ = enabled;
69    SetScale(kDefaultPartialMagnifiedScale);
70  } else {
71    SetScale(kNonPartialMagnifiedScale);
72    is_enabled_ = enabled;
73  }
74}
75
76////////////////////////////////////////////////////////////////////////////////
77// PartialMagnificationController: ui::EventHandler implementation
78
79void PartialMagnificationController::OnMouseEvent(ui::MouseEvent* event) {
80  if (IsPartialMagnified() && event->type() == ui::ET_MOUSE_MOVED) {
81    aura::Window* target = static_cast<aura::Window*>(event->target());
82    aura::Window* current_root = target->GetRootWindow();
83    // TODO(zork): Handle the case where the event is captured on a different
84    // display, such as when a menu is opened.
85    gfx::Rect root_bounds = current_root->bounds();
86
87    if (root_bounds.Contains(event->root_location())) {
88      SwitchTargetRootWindow(current_root);
89
90      OnMouseMove(event->root_location());
91    }
92  }
93}
94
95////////////////////////////////////////////////////////////////////////////////
96// PartialMagnificationController: aura::WindowObserver implementation
97
98void PartialMagnificationController::OnWindowDestroying(
99    aura::Window* window) {
100  CloseMagnifierWindow();
101
102  aura::Window* new_root_window = GetCurrentRootWindow();
103  if (new_root_window != window)
104    SwitchTargetRootWindow(new_root_window);
105}
106
107void PartialMagnificationController::OnWidgetDestroying(
108    views::Widget* widget) {
109  DCHECK_EQ(widget, zoom_widget_);
110  RemoveZoomWidgetObservers();
111  zoom_widget_ = NULL;
112}
113
114void PartialMagnificationController::OnMouseMove(
115    const gfx::Point& location_in_root) {
116  gfx::Point origin(location_in_root);
117
118  origin.Offset(-kMagnifierWidth / 2, -kMagnifierHeight / 2);
119
120  if (zoom_widget_) {
121    zoom_widget_->SetBounds(gfx::Rect(origin.x(), origin.y(),
122                                      kMagnifierWidth, kMagnifierHeight));
123  }
124}
125
126bool PartialMagnificationController::IsPartialMagnified() const {
127  return scale_ >= kMinPartialMagnifiedScaleThreshold;
128}
129
130void PartialMagnificationController::CreateMagnifierWindow() {
131  if (zoom_widget_)
132    return;
133
134  aura::Window* root_window = GetCurrentRootWindow();
135  if (!root_window)
136    return;
137
138  root_window->AddObserver(this);
139
140  gfx::Point mouse(root_window->GetDispatcher()->GetLastMouseLocationInRoot());
141
142  zoom_widget_ = new views::Widget;
143  views::Widget::InitParams params(
144      views::Widget::InitParams::TYPE_WINDOW_FRAMELESS);
145  params.can_activate = false;
146  params.accept_events = false;
147  params.opacity = views::Widget::InitParams::TRANSLUCENT_WINDOW;
148  params.parent = root_window;
149  zoom_widget_->Init(params);
150  zoom_widget_->SetBounds(gfx::Rect(mouse.x() - kMagnifierWidth / 2,
151                                    mouse.y() - kMagnifierHeight / 2,
152                                    kMagnifierWidth, kMagnifierHeight));
153  zoom_widget_->set_focus_on_creation(false);
154  zoom_widget_->Show();
155
156  aura::Window* window = zoom_widget_->GetNativeView();
157  window->SetName(kPartialMagniferWindowName);
158
159  zoom_widget_->GetNativeView()->layer()->SetBounds(
160      gfx::Rect(0, 0,
161                kMagnifierWidth,
162                kMagnifierHeight));
163  zoom_widget_->GetNativeView()->layer()->SetBackgroundZoom(
164      scale_,
165      kZoomInset);
166
167  zoom_widget_->AddObserver(this);
168}
169
170void PartialMagnificationController::CloseMagnifierWindow() {
171  if (zoom_widget_) {
172    RemoveZoomWidgetObservers();
173    zoom_widget_->Close();
174    zoom_widget_ = NULL;
175  }
176}
177
178void PartialMagnificationController::RemoveZoomWidgetObservers() {
179  DCHECK(zoom_widget_);
180  zoom_widget_->RemoveObserver(this);
181  aura::Window* root_window =
182      zoom_widget_->GetNativeView()->GetRootWindow();
183  DCHECK(root_window);
184  root_window->RemoveObserver(this);
185}
186
187void PartialMagnificationController::SwitchTargetRootWindow(
188    aura::Window* new_root_window) {
189  if (zoom_widget_ &&
190      new_root_window == zoom_widget_->GetNativeView()->GetRootWindow())
191    return;
192
193  CloseMagnifierWindow();
194
195  // Recreate the magnifier window by updating the scale factor.
196  SetScale(GetScale());
197}
198
199aura::Window* PartialMagnificationController::GetCurrentRootWindow() {
200  aura::Window::Windows root_windows = Shell::GetAllRootWindows();
201  for (aura::Window::Windows::const_iterator iter = root_windows.begin();
202       iter != root_windows.end(); ++iter) {
203    aura::Window* root_window = *iter;
204    if (root_window->ContainsPointInRoot(
205            root_window->GetDispatcher()->GetLastMouseLocationInRoot()))
206      return root_window;
207  }
208  return NULL;
209}
210
211}  // namespace ash
212