Show a visual indicator for the progress of auto-click.

chrome/browser/chromeos/ui/autoclick_ring_handler.cc

Index: chrome/browser/chromeos/ui/autoclick_ring_handler.cc
diff --git a/chrome/browser/chromeos/ui/autoclick_ring_handler.cc b/chrome/browser/chromeos/ui/autoclick_ring_handler.cc
new file mode 100644
index 0000000000000000000000000000000000000000..9f6f480d69d8ba0fe0704d03ff35b9f2fe32a49f
--- /dev/null
+++ b/chrome/browser/chromeos/ui/autoclick_ring_handler.cc
@@ -0,0 +1,326 @@
+// Copyright (c) 2016 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 "chrome/browser/chromeos/ui/autoclick_ring_handler.h"
+
+#include <memory>
+
+#include "ash/aura/wm_window_aura.h"
+#include "ash/common/shell_window_ids.h"
+#include "ash/common/wm/root_window_finder.h"
+#include "ash/root_window_controller.h"
+#include "ash/shell.h"
+#include "third_party/skia/include/core/SkColor.h"
+#include "third_party/skia/include/core/SkPaint.h"
+#include "third_party/skia/include/core/SkPath.h"
+#include "third_party/skia/include/core/SkRect.h"
+#include "ui/aura/client/screen_position_client.h"
+#include "ui/aura/env.h"
+#include "ui/aura/window.h"
+#include "ui/aura/window_event_dispatcher.h"
+#include "ui/compositor/layer.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/transform.h"
+#include "ui/views/view.h"
+#include "ui/views/widget/widget.h"
+#include "ui/wm/core/coordinate_conversion.h"
+
+namespace chromeos {
+namespace {
+
+const int kAutoclickRingOuterRadius = 30;
+const int kAutoclickRingInnerRadius = 20;
+
+// Angles from x-axis at which the outer and inner circles start.
+// const int kAutoclickRingOuterStartAngle = 0;
+const int kAutoclickRingInnerStartAngle = -90;
+
+const int kAutoclickRingGlowWidth = 20;
+// The following is half width to avoid division by 2.
+const int kAutoclickRingArcWidth = 2;
+
+// Start and end values for various animations.
+const double kAutoclickRingScaleStartValue = 1.0;
+const double kAutoclickRingScaleEndValue = 0.5;
+const double kAutoclickRingShrinkScaleEndValue = 0.5;
+const double kAutoclickRingOpacityStartValue = 0.1;
+const double kAutoclickRingOpacityEndValue = 0.5;
+const int kAutoclickRingAngleStartValue = -90;
+// The sweep angle is a bit greater than 360 to make sure the circle
+// completes at the end of the animation.
+const int kAutoclickRingAngleEndValue = 360;
+
+// Visual constants.
+const SkColor kAutoclickRingArcColor = SkColorSetARGB(255, 0, 255, 0);
+const SkColor kAutoclickRingCircleColor = SkColorSetARGB(255, 0, 0, 255);
+const int kAutoclickRingFrameRateHz = 60;
+
+views::Widget* CreateAutoclickRingWidget(aura::Window* root_window) {
+  views::Widget* widget = new views::Widget;
+  views::Widget::InitParams params;
+  params.type = views::Widget::InitParams::TYPE_WINDOW_FRAMELESS;
+  params.keep_on_top = true;
+  params.accept_events = false;
+  params.activatable = views::Widget::InitParams::ACTIVATABLE_NO;
+  params.ownership = views::Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
+  params.context = root_window;
+  params.opacity = views::Widget::InitParams::TRANSLUCENT_WINDOW;
+  widget->Init(params);
+  widget->SetOpacity(1.f);
+  ash::GetRootWindowController(root_window)
+      ->GetContainer(ash::kShellWindowId_OverlayContainer)
+      ->AddChild(widget->GetNativeWindow());
+  return widget;
+}
+
+void PaintAutoclickRingCircle(gfx::Canvas* canvas,
+                              gfx::Point& center,
+                              int radius) {
+  SkPaint paint;
+  paint.setStyle(SkPaint::kStroke_Style);
+  paint.setStrokeWidth(2 * kAutoclickRingArcWidth);
+  paint.setColor(kAutoclickRingCircleColor);
+  paint.setAntiAlias(true);
+
+  canvas->DrawCircle(center, radius, paint);
+}
+void PaintAutoclickRingArc(gfx::Canvas* canvas,
+                           gfx::Point& center,
+                           int radius,
+                           int start_angle,
+                           int end_angle) {
+  SkPaint paint;
+  paint.setStyle(SkPaint::kStroke_Style);
+  paint.setStrokeWidth(2 * kAutoclickRingArcWidth);
+  paint.setColor(kAutoclickRingArcColor);
+  paint.setAntiAlias(true);
+
+  SkPath arc_path;
+  arc_path.addArc(SkRect::MakeXYWH(center.x() - radius, center.y() - radius,
+                                   2 * radius, 2 * radius),
+                  start_angle, end_angle - start_angle);
+  canvas->DrawPath(arc_path, paint);
+}
+}  // namespace
+
+// View of the AutoclickRingHandler. Draws the actual contents and
+// updates as the animation proceeds. It also maintains the views::Widget that
+// the animation is shown in.
+class AutoclickRingHandler::AutoclickRingView : public views::View {
+ public:
+  AutoclickRingView(const gfx::Point& event_location, aura::Window* root_window)
+      : views::View(),
+        widget_(CreateAutoclickRingWidget(root_window)),
+        current_angle_(kAutoclickRingAngleStartValue),
+        current_scale_(kAutoclickRingScaleStartValue) {
+    widget_->SetContentsView(this);
+    widget_->SetAlwaysOnTop(true);
+
+    // We are owned by the AutoclickRing.
+    set_owned_by_client();
+    SetNewLocation(event_location, root_window);
+  }
+
+  ~AutoclickRingView() override {}
+
+  void SetNewLocation(const gfx::Point& new_event_location,
+                      aura::Window* root_window) {
+    gfx::Point point = new_event_location;
+    aura::client::GetScreenPositionClient(root_window)
+        ->ConvertPointToScreen(root_window, &point);
+    widget_->SetBounds(gfx::Rect(
+        point.x() - (kAutoclickRingOuterRadius + kAutoclickRingGlowWidth),
+        point.y() - (kAutoclickRingOuterRadius + kAutoclickRingGlowWidth),
+        GetPreferredSize().width(), GetPreferredSize().height()));
+    widget_->Show();
+    widget_->GetNativeView()->layer()->SetOpacity(
+        kAutoclickRingOpacityStartValue);
+  }
+
+  void UpdateWithGrowAnimation(gfx::Animation* animation) {
+    // Update the portion of the circle filled so far and re-draw.
+    current_angle_ = animation->CurrentValueBetween(
+        kAutoclickRingInnerStartAngle, kAutoclickRingAngleEndValue);
+    current_scale_ = animation->CurrentValueBetween(
+        kAutoclickRingScaleStartValue, kAutoclickRingScaleEndValue);
+    widget_->GetNativeView()->layer()->SetOpacity(
+        animation->CurrentValueBetween(kAutoclickRingOpacityStartValue,
+                                       kAutoclickRingOpacityEndValue));
+    SchedulePaint();
+  }
+
+  void UpdateWithShrinkAnimation(gfx::Animation* animation) {
+    current_scale_ = animation->CurrentValueBetween(
+        kAutoclickRingScaleEndValue, kAutoclickRingShrinkScaleEndValue);
+    widget_->GetNativeView()->layer()->SetOpacity(
+        animation->CurrentValueBetween(kAutoclickRingOpacityEndValue,
+                                       kAutoclickRingOpacityStartValue));
+    SchedulePaint();
+  }
+
+ private:
+  // Overridden from views::View.
+  gfx::Size GetPreferredSize() const override {
+    return gfx::Size(2 * (kAutoclickRingOuterRadius + kAutoclickRingGlowWidth),
+                     2 * (kAutoclickRingOuterRadius + kAutoclickRingGlowWidth));
+  }
+
+  void OnPaint(gfx::Canvas* canvas) override {
+    gfx::Point center(GetPreferredSize().width() / 2,
+                      GetPreferredSize().height() / 2);
+    canvas->Save();
+
+    gfx::Transform scale;
+    scale.Scale(current_scale_, current_scale_);
+    // We want to scale from the center.
+    canvas->Translate(center.OffsetFromOrigin());
+    canvas->Transform(scale);
+    canvas->Translate(-center.OffsetFromOrigin());
+
+    // Paint inner circle.
+    PaintAutoclickRingArc(canvas, center, kAutoclickRingInnerRadius,
+                          kAutoclickRingInnerStartAngle, current_angle_);
+    // Paint outer circle.
+    PaintAutoclickRingCircle(canvas, center, kAutoclickRingOuterRadius);
+
+    canvas->Restore();
+  }
+
+  std::unique_ptr<views::Widget> widget_;
+  int current_angle_;
+  double current_scale_;
+
+  DISALLOW_COPY_AND_ASSIGN(AutoclickRingView);
+};
+
+////////////////////////////////////////////////////////////////////////////////
+
+// AutoclickRingHandler, public
+AutoclickRingHandler::AutoclickRingHandler()
+    : gfx::LinearAnimation(kAutoclickRingFrameRateHz, nullptr),
+      tap_down_target_(nullptr),
+      current_animation_type_(NONE) {}
+
+AutoclickRingHandler::~AutoclickRingHandler() {
+  StopAutoclickRing();
+}
+
+void AutoclickRingHandler::StartGesture(int duration_ms, gfx::Point center) {
+  aura::Window* target = GetTargetWindow();
+  if (tap_down_target_ && tap_down_target_ != target)
+    return;
+  StopAutoclickRing();
+  SetTapDownTarget();
+  tap_down_location_ = center;
+  current_animation_type_ = GROW_ANIMATION;
+  StartAnimation(duration_ms);
+}
+
+void AutoclickRingHandler::StopGesture() {
+  aura::Window* target = GetTargetWindow();
+  if (tap_down_target_ && tap_down_target_ != target)
+    return;
+  StopAutoclickRing();
+}
+
+void AutoclickRingHandler::SetGestureCenter(gfx::Point center) {
+  tap_down_location_ = center;
+}
+////////////////////////////////////////////////////////////////////////////////
+// AutoclickRingHandler, private
+aura::Window* AutoclickRingHandler::GetTargetWindow() {
+  aura::Window* target = ash::WmWindowAura::GetAuraWindow(
+      ash::wm::GetRootWindowAt(tap_down_location_));
+  DCHECK(target) << "Root window not found while rendering autoclick circle;";
+  return target;
+}
+
+void AutoclickRingHandler::SetTapDownTarget() {
+  aura::Window* target = GetTargetWindow();
+  SetTapDownTarget(target);
+}
+
+void AutoclickRingHandler::StartAnimation(int delay_ms) {
+  switch (current_animation_type_) {
+    case GROW_ANIMATION: {
+      aura::Window* root_window = tap_down_target_->GetRootWindow();
+      if (!root_window) {
+        StopAutoclickRing();
+        return;
+      }
+      view_.reset(new AutoclickRingView(tap_down_location_, root_window));
+      SetDuration(delay_ms);
+      Start();
+      break;
+    }
+    case SHRINK_ANIMATION:
+      SetDuration(delay_ms);
+      Start();
+      break;
+    default:
+      NOTREACHED();
+      break;
+  }
+}
+
+void AutoclickRingHandler::StopAutoclickRing() {
+  // Since, Animation::Stop() calls AnimationStopped(), we need to reset the
+  // |current_animation_type_| before Stop(), otherwise AnimationStopped() may
+  // start the timer again.
+  current_animation_type_ = NONE;
+  Stop();
+  view_.reset();
+  SetTapDownTarget(nullptr);
+}
+
+void AutoclickRingHandler::SetTapDownTarget(aura::Window* target) {
+  if (tap_down_target_ == target)
+    return;
+
+  if (tap_down_target_)
+    tap_down_target_->RemoveObserver(this);
+  tap_down_target_ = target;
+  if (tap_down_target_)
+    tap_down_target_->AddObserver(this);
+}
+
+void AutoclickRingHandler::AnimateToState(double state) {
+  DCHECK(view_.get());
+  switch (current_animation_type_) {
+    case GROW_ANIMATION:
+      view_->SetNewLocation(tap_down_location_, GetTargetWindow());
+      view_->UpdateWithGrowAnimation(this);
+      break;
+    case SHRINK_ANIMATION:
+      view_->SetNewLocation(tap_down_location_, GetTargetWindow());
+      view_->UpdateWithShrinkAnimation(this);
+      break;
+    default:
+      NOTREACHED();
+      break;
+  }
+}
+
+void AutoclickRingHandler::AnimationStopped() {
+  switch (current_animation_type_) {
+    case GROW_ANIMATION:
+      current_animation_type_ = SHRINK_ANIMATION;
+      StartAnimation(0);
+      break;
+    case SHRINK_ANIMATION:
+      current_animation_type_ = NONE;
+    // fall through to reset the view.
+    default:
+      view_.reset();
+      SetTapDownTarget(nullptr);
+      break;
+  }
+}
+
+void AutoclickRingHandler::OnWindowDestroying(aura::Window* window) {
+  DCHECK_EQ(tap_down_target_, window);
+  StopAutoclickRing();
+}
+
+}  // namespace chromeos