Improve switch between gestures and touch mode when kEnableTouchEvents

content/browser/renderer_host/render_widget_host_view_win.cc

 // Copyright (c) 2012 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/render_widget_host_view_win.h"
 
 #include <algorithm>
 #include <peninputpanel_i.c>
 
 #include "base/bind.h"
@@ skipping 311 matching lines @@
       parent_hwnd_(NULL),
       is_loading_(false),
       text_input_type_(ui::TEXT_INPUT_TYPE_NONE),
       is_fullscreen_(false),
       ignore_mouse_movement_(true),
       composition_range_(ui::Range::InvalidRange()),
       touch_state_(this),
       pointer_down_context_(false),
       focus_on_editable_field_(false),
       received_focus_change_after_pointer_down_(false),
-      transparent_region_(0) {
+      transparent_region_(0),
+      touch_events_enabled_(false) {
   render_widget_host_ = static_cast<RenderWidgetHostImpl*>(widget);
   render_widget_host_->SetView(this);
   registrar_.Add(this,
                  content::NOTIFICATION_RENDERER_PROCESS_TERMINATED,
                  content::NotificationService::AllBrowserContextsAndSources());
   registrar_.Add(this,
                  content::NOTIFICATION_FOCUS_CHANGED_IN_PAGE,
                  content::NotificationService::AllBrowserContextsAndSources());
 }
 
@@ skipping 560 matching lines @@
 
 void RenderWidgetHostViewWin::SetBackground(const SkBitmap& background) {
   content::RenderWidgetHostViewBase::SetBackground(background);
   render_widget_host_->SetBackground(background);
 }
 
 void RenderWidgetHostViewWin::UnhandledWheelEvent(
     const WebKit::WebMouseWheelEvent& event) {
 }
 
-void RenderWidgetHostViewWin::ProcessTouchAck(bool processed) {
+void RenderWidgetHostViewWin::ProcessTouchAck(
+    WebKit::WebInputEvent::Type type, bool processed) {
+  if (type == WebKit::WebInputEvent::TouchStart)
+    UpdateDesiredTouchMode(processed);
+}
+
+void RenderWidgetHostViewWin::SetToGestureMode() {
+  UnregisterTouchWindow(m_hWnd);
+  // Single finger panning is consistent with other windows applications.
+  const DWORD gesture_allow = GC_PAN_WITH_SINGLE_FINGER_VERTICALLY |
+                              GC_PAN_WITH_SINGLE_FINGER_HORIZONTALLY;
+  const DWORD gesture_block = GC_PAN_WITH_GUTTER;
+  GESTURECONFIG gc[] = {
+      { GID_ZOOM, GC_ZOOM, 0 },
+      { GID_PAN, gesture_allow , gesture_block},
+      { GID_TWOFINGERTAP, GC_TWOFINGERTAP , 0},
+      { GID_PRESSANDTAP, GC_PRESSANDTAP , 0}
+  };
+  if (!SetGestureConfig(m_hWnd, 0, arraysize(gc), gc,
+      sizeof(GESTURECONFIG))) {
+    NOTREACHED();
+  }
+  touch_events_enabled_ = false;
+}
+
+bool RenderWidgetHostViewWin::SetToTouchMode() {
+  bool touch_mode = !!RegisterTouchWindow(m_hWnd, TWF_WANTPALM);

[cpu_(ooo_6.6-7.5), 2012/03/02 21:26:36]

we're not fans of the !! construct, you can use foo == TRUE

[scottmg, 2012/03/02 22:27:29]

Done.

+  touch_events_enabled_ = touch_mode;
+  return touch_mode;
+}
+
+void RenderWidgetHostViewWin::UpdateDesiredTouchMode(bool touch_mode) {
+  // Make sure that touch events even make sense.
+  bool touch_mode_valid = base::win::GetVersion() >= base::win::VERSION_WIN7 &&
+      CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnableTouchEvents);
+  touch_mode = touch_mode && touch_mode_valid;
+
+  // Already in correct mode, nothing to do.
+  if ((touch_mode && touch_events_enabled_) ||
+      (!touch_mode && !touch_events_enabled_))
+    return;
+
+  // Now we know that the window's current state doesn't match the desired
+  // state. If we want touch mode, then we attempt to register for touch
+  // events, and otherwise to unregister.
+  if (touch_mode) {
+    touch_mode = SetToTouchMode();
+  }
+  if (!touch_mode) {
+    SetToGestureMode();
+  }
 }
 
 void RenderWidgetHostViewWin::SetHasHorizontalScrollbar(
     bool has_horizontal_scrollbar) {
 }
 
 void RenderWidgetHostViewWin::SetScrollOffsetPinning(
     bool is_pinned_to_left, bool is_pinned_to_right) {
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostViewWin, private:
 
 LRESULT RenderWidgetHostViewWin::OnCreate(CREATESTRUCT* create_struct) {
   // Call the WM_INPUTLANGCHANGE message handler to initialize the input locale
   // of a browser process.
   OnInputLangChange(0, 0);
   // Marks that window as supporting mouse-wheel messages rerouting so it is
   // scrolled when under the mouse pointer even if inactive.
   props_.push_back(ui::SetWindowSupportsRerouteMouseWheel(m_hWnd));
 
-  if (base::win::GetVersion() >= base::win::VERSION_WIN7) {
-    // Use gestures if touch event switch isn't present or registration fails.
-    if (!CommandLine::ForCurrentProcess()->HasSwitch(
-            switches::kEnableTouchEvents) ||
-        !RegisterTouchWindow(m_hWnd, TWF_WANTPALM)) {
-      // Single finger panning is consistent with other windows applications.
-      const DWORD gesture_allow = GC_PAN_WITH_SINGLE_FINGER_VERTICALLY |
-                                  GC_PAN_WITH_SINGLE_FINGER_HORIZONTALLY;
-      const DWORD gesture_block = GC_PAN_WITH_GUTTER;
-      GESTURECONFIG gc[] = {
-          { GID_ZOOM, GC_ZOOM, 0 },
-          { GID_PAN, gesture_allow , gesture_block},
-          { GID_TWOFINGERTAP, GC_TWOFINGERTAP , 0},
-          { GID_PRESSANDTAP, GC_PRESSANDTAP , 0}
-      };
-      if (!SetGestureConfig(m_hWnd, 0, arraysize(gc), gc,
-          sizeof(GESTURECONFIG))) {
-        NOTREACHED();
-      }
-    }
-  }
+  SetToGestureMode();
+
   return 0;
 }
 
 void RenderWidgetHostViewWin::OnActivate(UINT action, BOOL minimized,
                                          HWND window) {
   // If the container is a popup, clicking elsewhere on screen should close the
   // popup.
   if (close_on_deactivate_ && action == WA_INACTIVE) {
     // Send a windows message so that any derived classes
     // will get a change to override the default handling
@@ skipping 933 matching lines @@
     }
   } else if (gi.dwID == GID_PAN) {
     // Right now we only decode scroll gestures and we forward to the page
     // as scroll events.
     POINT start;
     POINT delta;
     if (DecodeScrollGesture(gi, &start, &delta)) {
       handled = TRUE;
       render_widget_host_->ForwardWheelEvent(
           MakeFakeScrollWheelEvent(m_hWnd, start, delta));
+
+      // Send a touch event at this location; if the touch start is handled
+      // then we switch to touch mode, rather than gesture mode (in the ACK).
+      TOUCHINPUT fake_touch;

[cpu_(ooo_6.6-7.5), 2012/03/02 21:26:36]

sounds like we send the fake a lot of times if we never switch to touch mode?

Come by to talk.

[scottmg, 2012/03/02 22:27:29]

Good point, thanks. Changed to only send fake touch on GID_BEGIN.

+      fake_touch.x = gi.ptsLocation.x * 100;
+      fake_touch.y = gi.ptsLocation.y * 100;
+      fake_touch.cxContact = 100;
+      fake_touch.cyContact = 100;
+      fake_touch.dwMask = 0;
+      fake_touch.dwFlags = TOUCHEVENTF_DOWN | TOUCHEVENTF_PRIMARY;
+      fake_touch.dwID = gi.dwInstanceID;
+      touch_state_.UpdateTouchPoints(&fake_touch, 1);
+      if (touch_state_.is_changed())
+        render_widget_host_->ForwardTouchEvent(touch_state_.touch_event());
     }
+  } else if (gi.dwID == GID_END) {
+    if (touch_state_.ReleaseTouchPoints())
+      render_widget_host_->ForwardTouchEvent(touch_state_.touch_event());
   }
   ::CloseGestureInfoHandle(gi_handle);
   return 0;
 }
 
 void RenderWidgetHostViewWin::OnAccessibilityNotifications(
     const std::vector<AccessibilityHostMsg_NotificationParams>& params) {
   if (!GetBrowserAccessibilityManager()) {
     SetBrowserAccessibilityManager(
         BrowserAccessibilityManager::CreateEmptyDocument(
@@ skipping 679 matching lines @@
 void RenderWidgetHostViewWin::ResetPointerDownContext() {
   // If the default focus on the page is on an edit field and we did not
   // receive a focus change in the context of a pointer down message, it means
   // that the pointer down message occurred on the edit field and we should
   // display the on screen keyboard
   if (!received_focus_change_after_pointer_down_ && virtual_keyboard_)
     DisplayOnScreenKeyboardIfNeeded();
   received_focus_change_after_pointer_down_ = false;
   pointer_down_context_ = false;
 }