[DevTools] Touch emulation in content.

content/browser/renderer_host/input/touch_emulator.cc

+// Copyright 2014 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 "content/browser/renderer_host/input/touch_emulator.h"
+
+#include "content/browser/renderer_host/input/motion_event_web.h"
+#include "content/browser/renderer_host/input/web_input_event_util.h"
+#include "content/public/common/content_client.h"
+#include "content/public/common/content_switches.h"
+#include "grit/content_resources.h"
+#include "third_party/WebKit/public/platform/WebCursorInfo.h"
+#include "ui/events/gesture_detection/gesture_config_helper.h"
+#include "ui/gfx/image/image.h"
+
+using blink::WebGestureEvent;
+using blink::WebInputEvent;
+using blink::WebKeyboardEvent;
+using blink::WebMouseEvent;
+using blink::WebMouseWheelEvent;
+using blink::WebTouchEvent;
+using blink::WebTouchPoint;
+
+namespace content {
+
+namespace {
+
+ui::GestureProvider::Config GetGestureProviderConfig() {
+  // TODO(dgozman): Use different configs to emulate mobile/desktop as
+  // requested by renderer.
+  ui::GestureProvider::Config config = ui::DefaultGestureProviderConfig();
+  config.gesture_begin_end_types_enabled = false;
+  return config;
+}
+
+// Time between two consecutive mouse moves, during which second mouse move
+// is not converted to touch.
+const double kMouseMoveDropIntervalSeconds = 5.f / 1000;
+
+} // namespace
+
+TouchEmulator::TouchEmulator(TouchEmulatorClient* client)
+    : client_(client),
+      gesture_provider_(GetGestureProviderConfig(), this),
+      enabled_(false),
+      allow_pinch_(false) {
+  DCHECK(client_);
+  ResetState();
+
+  InitCursorFromResource(&touch_cursor_, IDR_DEVTOOLS_TOUCH_CURSOR_ICON);
+  InitCursorFromResource(&pinch_cursor_, IDR_DEVTOOLS_PINCH_CURSOR_ICON);
+
+  WebCursor::CursorInfo cursor_info;
+  cursor_info.type = blink::WebCursorInfo::TypePointer;
+  pointer_cursor_.InitFromCursorInfo(cursor_info);
+
+  // TODO(dgozman): Use synthetic secondary touch to support multi-touch.
+  gesture_provider_.SetMultiTouchSupportEnabled(false);
+  // TODO(dgozman): Enable double tap if requested by the renderer.
+  // TODO(dgozman): Don't break double-tap-based pinch with shift handling.
+  gesture_provider_.SetDoubleTapSupportForPlatformEnabled(false);
+}
+
+TouchEmulator::~TouchEmulator() {
+  // We cannot cleanup properly in destructor, as we need roundtrip to the
+  // renderer for ack. Instead, the owner should call Disable, and only
+  // destroy this object when renderer is dead.
+}
+
+void TouchEmulator::ResetState() {
+  last_mouse_event_was_move_ = false;
+  last_mouse_move_timestamp_ = 0;
+  mouse_pressed_ = false;
+  shift_pressed_ = false;
+  touch_active_ = false;
+  suppress_next_fling_cancel_ = false;
+  pinch_scale_ = 1.f;
+  pinch_gesture_active_ = false;
+}
+
+void TouchEmulator::Enable(bool allow_pinch) {
+  if (!enabled_) {
+    enabled_ = true;
+    ResetState();
+  }
+  allow_pinch_ = allow_pinch;
+  UpdateCursor();
+}
+
+void TouchEmulator::Disable() {
+  if (!enabled_)
+    return;
+
+  enabled_ = false;
+  UpdateCursor();
+  CancelTouch();
+}
+
+void TouchEmulator::InitCursorFromResource(WebCursor* cursor, int resource_id) {
+  gfx::Image& cursor_image =
+      content::GetContentClient()->GetNativeImageNamed(resource_id);
+  WebCursor::CursorInfo cursor_info;
+  cursor_info.type = blink::WebCursorInfo::TypeCustom;
+  // TODO(dgozman): Add HiDPI cursors.
+  cursor_info.image_scale_factor = 1.f;
+  cursor_info.custom_image = cursor_image.AsBitmap();
+  cursor_info.hotspot =
+      gfx::Point(cursor_image.Width() / 2, cursor_image.Height() / 2);
+#if defined(OS_WIN)
+  cursor_info.external_handle = 0;
+#endif
+
+  cursor->InitFromCursorInfo(cursor_info);
+}
+
+bool TouchEmulator::HandleMouseEvent(const WebMouseEvent& mouse_event) {
+  if (!enabled_)
+    return false;
+
+  if (mouse_event.button != WebMouseEvent::ButtonLeft)
+    return true;
+
+  if (mouse_event.type == WebInputEvent::MouseMove) {
+    if (last_mouse_event_was_move_ &&
+        mouse_event.timeStampSeconds < last_mouse_move_timestamp_ +
+            kMouseMoveDropIntervalSeconds)
+      return true;
+
+    last_mouse_event_was_move_ = true;
+    last_mouse_move_timestamp_ = mouse_event.timeStampSeconds;
+  } else {
+    last_mouse_event_was_move_ = false;
+  }
+
+  if (mouse_event.type == WebInputEvent::MouseDown)
+    mouse_pressed_ = true;
+  else if (mouse_event.type == WebInputEvent::MouseUp)
+    mouse_pressed_ = false;
+
+  UpdateShiftPressed((mouse_event.modifiers & WebInputEvent::ShiftKey) != 0);
+
+  if (FillTouchEventAndPoint(mouse_event) &&
+      gesture_provider_.OnTouchEvent(MotionEventWeb(touch_event_))) {
+    client_->ForwardTouchEvent(touch_event_);
+  }
+
+  // Do not pass mouse events to the renderer.
+  return true;
+}
+
+bool TouchEmulator::HandleMouseWheelEvent(const WebMouseWheelEvent& event) {
+  if (!enabled_)
+    return false;
+
+  // No mouse wheel events for the renderer.
+  return true;
+}
+
+bool TouchEmulator::HandleKeyboardEvent(const WebKeyboardEvent& event) {
+  if (!enabled_)
+    return false;
+
+  if (!UpdateShiftPressed((event.modifiers & WebInputEvent::ShiftKey) != 0))
+    return false;
+
+  if (!mouse_pressed_)
+    return false;
+
+  // Note: The necessary pinch events will be lazily inserted by
+  // |OnGestureEvent| depending on the state of |shift_pressed_|, using the
+  // scroll stream as the event driver.
+  if (shift_pressed_) {
+    // TODO(dgozman): Add secondary touch point and set anchor.
+  } else {
+    // TODO(dgozman): Remove secondary touch point and anchor.
+  }
+
+  // Never block keyboard events.
+  return false;
+}
+
+bool TouchEmulator::HandleTouchEventAck(InputEventAckState ack_result) {
+  const bool event_consumed = ack_result == INPUT_EVENT_ACK_STATE_CONSUMED;
+  gesture_provider_.OnTouchEventAck(event_consumed);
+  // TODO(dgozman): Disable emulation when real touch events are available.
+  return true;
+}
+
+void TouchEmulator::OnGestureEvent(const ui::GestureEventData& gesture) {
+  WebGestureEvent gesture_event =
+      CreateWebGestureEventFromGestureEventData(gesture);
+
+  switch (gesture_event.type) {
+    case WebInputEvent::GestureScrollBegin:
+      client_->ForwardGestureEvent(gesture_event);
+      // PinchBegin must always follow ScrollBegin.
+      if (InPinchGestureMode())
+        PinchBegin(gesture_event);
+      break;
+
+    case WebInputEvent::GestureScrollUpdate:
+      if (InPinchGestureMode()) {
+        // Convert scrolls to pinches while shift is pressed.
+        if (!pinch_gesture_active_)
+          PinchBegin(gesture_event);
+        else
+          PinchUpdate(gesture_event);
+      } else {
+        // Pass scroll update further. If shift was released, end the pinch.
+        if (pinch_gesture_active_)
+          PinchEnd(gesture_event);
+        client_->ForwardGestureEvent(gesture_event);
+      }
+      break;
+
+    case WebInputEvent::GestureScrollEnd:
+      // PinchEnd must precede ScrollEnd.
+      if (pinch_gesture_active_)
+        PinchEnd(gesture_event);
+      client_->ForwardGestureEvent(gesture_event);
+      break;
+
+    case WebInputEvent::GestureFlingStart:
+      // PinchEnd must precede FlingStart.
+      if (pinch_gesture_active_)
+        PinchEnd(gesture_event);
+      if (InPinchGestureMode()) {
+        // No fling in pinch mode. Forward scroll end instead of fling start.
+        suppress_next_fling_cancel_ = true;
+        ScrollEnd(gesture_event);
+      } else {
+        suppress_next_fling_cancel_ = false;
+        client_->ForwardGestureEvent(gesture_event);
+      }
+      break;
+
+    case WebInputEvent::GestureFlingCancel:
+      // If fling start was suppressed, we should not send fling cancel either.
+      if (!suppress_next_fling_cancel_)
+        client_->ForwardGestureEvent(gesture_event);
+      suppress_next_fling_cancel_ = false;
+      break;
+
+    default:
+      // Everything else goes through.
+      client_->ForwardGestureEvent(gesture_event);
+  }
+}
+
+void TouchEmulator::CancelTouch() {
+  if (!touch_active_)
+    return;
+
+  touch_event_.timeStampSeconds =
+      (base::TimeTicks::Now() - base::TimeTicks()).InSecondsF();
+  touch_event_.type = WebInputEvent::TouchCancel;
+  touch_event_.touches[0].state = WebTouchPoint::StateCancelled;
+  touch_active_ = false;
+  if (gesture_provider_.OnTouchEvent(MotionEventWeb(touch_event_)))
+    client_->ForwardTouchEvent(touch_event_);
+}
+
+void TouchEmulator::UpdateCursor() {
+  if (!enabled_)
+    client_->SetCursor(pointer_cursor_);
+  else
+    client_->SetCursor(InPinchGestureMode() ? pinch_cursor_ : touch_cursor_);
+}
+
+bool TouchEmulator::UpdateShiftPressed(bool shift_pressed) {
+  if (shift_pressed_ == shift_pressed)
+    return false;
+  shift_pressed_ = shift_pressed;
+  UpdateCursor();
+  return true;
+}
+
+void TouchEmulator::PinchBegin(const WebGestureEvent& event) {
+  DCHECK(InPinchGestureMode());
+  DCHECK(!pinch_gesture_active_);
+  pinch_gesture_active_ = true;
+  pinch_anchor_ = gfx::Point(event.x, event.y);
+  pinch_scale_ = 1.f;
+  FillPinchEvent(event);
+  pinch_event_.type = WebInputEvent::GesturePinchBegin;
+  client_->ForwardGestureEvent(pinch_event_);
+}
+
+void TouchEmulator::PinchUpdate(const WebGestureEvent& event) {
+  DCHECK(pinch_gesture_active_);
+  int dy = pinch_anchor_.y() - event.y;
+  float scale = exp(dy * 0.002f);
+  FillPinchEvent(event);
+  pinch_event_.type = WebInputEvent::GesturePinchUpdate;
+  pinch_event_.data.pinchUpdate.scale = scale / pinch_scale_;
+  client_->ForwardGestureEvent(pinch_event_);
+  pinch_scale_ = scale;
+}
+
+void TouchEmulator::PinchEnd(const WebGestureEvent& event) {
+  DCHECK(pinch_gesture_active_);
+  pinch_gesture_active_ = false;
+  FillPinchEvent(event);
+  pinch_event_.type = WebInputEvent::GesturePinchEnd;
+  client_->ForwardGestureEvent(pinch_event_);
+}
+
+void TouchEmulator::FillPinchEvent(const WebInputEvent& event) {
+  pinch_event_.timeStampSeconds = event.timeStampSeconds;
+  pinch_event_.modifiers = event.modifiers;
+  pinch_event_.sourceDevice = blink::WebGestureEvent::Touchscreen;
+  pinch_event_.x = pinch_anchor_.x();
+  pinch_event_.y = pinch_anchor_.y();
+}
+
+void TouchEmulator::ScrollEnd(const WebGestureEvent& event) {
+  WebGestureEvent scroll_event;
+  scroll_event.timeStampSeconds = event.timeStampSeconds;
+  scroll_event.modifiers = event.modifiers;
+  scroll_event.sourceDevice = blink::WebGestureEvent::Touchscreen;
+  scroll_event.type = WebInputEvent::GestureScrollEnd;
+  client_->ForwardGestureEvent(scroll_event);
+}
+
+bool TouchEmulator::FillTouchEventAndPoint(const WebMouseEvent& mouse_event) {
+  if (mouse_event.type != WebInputEvent::MouseDown &&
+      mouse_event.type != WebInputEvent::MouseMove &&
+      mouse_event.type != WebInputEvent::MouseUp) {
+    return false;
+  }
+
+  touch_event_.touchesLength = 1;
+  touch_event_.timeStampSeconds = mouse_event.timeStampSeconds;
+  touch_event_.modifiers = mouse_event.modifiers;
+
+  WebTouchPoint& point = touch_event_.touches[0];
+  point.id = 0;
+  point.radiusX = point.radiusY = 1.f;
+  point.force = 1.f;
+  point.rotationAngle = 0.f;
+  point.position.x = mouse_event.x;
+  point.screenPosition.x = mouse_event.globalX;
+  point.position.y = mouse_event.y;
+  point.screenPosition.y = mouse_event.globalY;
+
+  switch (mouse_event.type) {
+    case WebInputEvent::MouseDown:
+      touch_event_.type = WebInputEvent::TouchStart;
+      touch_active_ = true;
+      point.state = WebTouchPoint::StatePressed;
+      break;
+    case WebInputEvent::MouseMove:
+      touch_event_.type = WebInputEvent::TouchMove;
+      point.state = WebTouchPoint::StateMoved;
+      break;
+    case WebInputEvent::MouseUp:
+      touch_event_.type = WebInputEvent::TouchEnd;
+      touch_active_ = false;
+      point.state = WebTouchPoint::StateReleased;
+      break;
+    default:
+      NOTREACHED();
+  }
+  return true;
+}
+
+bool TouchEmulator::InPinchGestureMode() const {
+  return shift_pressed_ && allow_pinch_;
+}
+
+}  // namespace content