[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;
+}
+
+} // namespace
+
+TouchEmulator::TouchEmulator(TouchEmulatorClient* client)
+    : client_(client),
+      gesture_provider_(GetGestureProviderConfig(), this) {
+  Init();
+}
+
+TouchEmulator::TouchEmulator(TouchEmulatorClient* client,
+                             ui::GestureProvider::Config gesture_config)
+    : client_(client),
+      gesture_provider_(gesture_config, this) {
+  Init();
+}
+
+void TouchEmulator::Init() {
+  DCHECK(client_);
+  enabled_ = false;
+  mouse_pressed_ = false;
+  shift_pressed_ = false;
+  touch_active_ = false;
+  scroll_gesture_active_ = false;
+  fling_start_suppressed_ = false;
+  pinch_scale_ = 1.f;
+  pinch_gesture_active_ = false;
+
+  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() {
+  if (enabled_) {

[jdduke (slow), 2014/04/08 19:14:11]

Actually, the safest thing here would be to do nothing, and put a comment that
the owner is responsible for any event cleanup.  The reason is, we only destroy
the emulator if the renderer has crashed, so there's no need for cleanup.

[dgozman, 2014/04/09 17:00:05]

Sounds reasonable. Done.

+    // Try to cleanup gestures at least.
+    if (pinch_gesture_active_) {
+      pinch_event_.timeStampSeconds = base::Time::Now().ToDoubleT();
+      PinchEnd(pinch_event_);
+    }
+    if (scroll_gesture_active_) {
+      pinch_event_.timeStampSeconds = base::Time::Now().ToDoubleT();
+      ScrollEnd(pinch_event_);
+    }
+  }
+}
+
+void TouchEmulator::Enable() {
+  if (enabled_)
+    return;
+
+  enabled_ = true;
+  shift_pressed_ = false;
+  mouse_pressed_ = false;
+  touch_active_ = false;
+  scroll_gesture_active_ = false;
+  fling_start_suppressed_ = false;
+  pinch_gesture_active_ = false;
+  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::MouseDown)
+    mouse_pressed_ = true;
+  if (mouse_event.type == WebInputEvent::MouseUp)

[jdduke (slow), 2014/04/08 19:14:11]

Nit: else if

[dgozman, 2014/04/09 17:00:05]

Done.

+    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, 1);
+
+  // Convert scrolls to pinches while shift is pressed.

[jdduke (slow), 2014/04/08 19:14:11]

I wonder if this method would be easier to follow with a switch
(gesture_event.type), in which the final statement is
|client_->ForwardGestureEvent()| and we return early where necessary.  It took
me a while to find that line =/.  Just a thought.

[dgozman, 2014/04/09 17:00:05]

Switch looks better. However, we still need different places for
|client_->ForwardGestureEvent()| as the logic is somewhat complex.

+  if (gesture_event.type == WebInputEvent::GestureScrollUpdate) {
+    if (InPinchGestureMode()) {
+      if (!pinch_gesture_active_)
+        PinchBegin(gesture_event);
+      else
+        PinchUpdate(gesture_event);
+      return;
+    } else {
+      if (pinch_gesture_active_)
+        PinchEnd(gesture_event);
+    }
+  }
+
+  if ((gesture_event.type == WebInputEvent::GestureScrollEnd ||
+       gesture_event.type == WebInputEvent::GestureFlingStart)) {
+    scroll_gesture_active_ = false;
+    // PinchEnd must always precede ScrollEnd/FlingStart.
+    if (pinch_gesture_active_)
+      PinchEnd(gesture_event);
+  }
+
+  if (gesture_event.type == WebInputEvent::GestureFlingStart &&
+      InPinchGestureMode()) {
+    // No fling in pinch mode. Forward scroll end instead of fling start.
+    fling_start_suppressed_ = true;
+    ScrollEnd(gesture_event);
+  } else {
+    bool suppress_fling_cancel =
+        gesture_event.type == WebInputEvent::GestureFlingCancel &&
+        fling_start_suppressed_;
+    if (!suppress_fling_cancel)
+      client_->ForwardGestureEvent(gesture_event);
+    if (gesture_event.type == WebInputEvent::GestureFlingStart ||
+        gesture_event.type == WebInputEvent::GestureFlingCancel)
+      fling_start_suppressed_ = false;
+    // TODO(dgozman): sometimes we hit a race, where keyboard event cancels
+    // fling in browser process, but does not in renderer process.
+  }
+
+  if (gesture_event.type == WebInputEvent::GestureScrollBegin) {
+    scroll_gesture_active_ = true;
+    // PinchBegin must always follow ScrollBegin.
+    if (InPinchGestureMode())
+      PinchBegin(gesture_event);
+  }
+}
+
+void TouchEmulator::CancelTouch() {
+  if (!touch_active_)
+    return;
+
+  touch_event_.timeStampSeconds = base::Time::Now().ToDoubleT();
+  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_;
+}
+
+}  // namespace content