Fixed scrolling for mixed-valuator mouse

ui/events/x/events_x_utils.cc

 // 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 "ui/events/x/events_x_utils.h"
 
 #include <stddef.h>
 #include <string.h>
 #include <X11/extensions/XInput.h>
 #include <X11/extensions/XInput2.h>
@@ skipping 608 matching lines @@
 gfx::Vector2d GetMouseWheelOffsetFromXEvent(const XEvent& xev) {
   float x_offset, y_offset;
   if (GetScrollOffsetsFromXEvent(xev, &x_offset, &y_offset, NULL, NULL, NULL)) {
     return gfx::Vector2d(static_cast<int>(x_offset),
                          static_cast<int>(y_offset));
   }
 
   int button = xev.type == GenericEvent ? EventButtonFromXEvent(xev)
                                         : xev.xbutton.button;
 
+  // If this is an xinput1 scroll event from an xinput2 mouse then we need to
+  // block the legacy scroll events for the necessary axes.

[sadrul, 2016/04/19 14:28:24]

For mouse-press/releases on a normal mouse device, X11 can send both xinput1 and
xinput2 versions of events. But from what I have seen, if chrome listens for
XInput2 events (using XISelectEvents), then chrome does not get the xinput1
version of the events. Is that not the case for these scroll events?

+  int scroll_class_type =
+      DeviceDataManagerX11::GetInstance()->GetScrollClassDeviceDetail(xev);
+  bool xi2_vertical = scroll_class_type & SCROLL_TYPE_VERTICAL;
+  bool xi2_horizontal = scroll_class_type & SCROLL_TYPE_HORIZONTAL;
+
   switch (button) {
     case 4:
-      return gfx::Vector2d(0, kWheelScrollAmount);
+      return gfx::Vector2d(0, xi2_vertical ? 0 : kWheelScrollAmount);
     case 5:
-      return gfx::Vector2d(0, -kWheelScrollAmount);
+      return gfx::Vector2d(0, xi2_vertical ? 0 : -kWheelScrollAmount);
     case 6:
-      return gfx::Vector2d(kWheelScrollAmount, 0);
+      return gfx::Vector2d(xi2_horizontal ? 0 : kWheelScrollAmount, 0);
     case 7:
-      return gfx::Vector2d(-kWheelScrollAmount, 0);
+      return gfx::Vector2d(xi2_horizontal ? 0 : -kWheelScrollAmount, 0);
     default:
       return gfx::Vector2d();
   }
 }
 
 void ClearTouchIdIfReleasedFromXEvent(const XEvent& xev) {
   ui::EventType type = ui::EventTypeFromXEvent(xev);
   if (type == ui::ET_TOUCH_CANCELLED || type == ui::ET_TOUCH_RELEASED) {
     ui::TouchFactory* factory = ui::TouchFactory::GetInstance();
     ui::DeviceDataManagerX11* manager = ui::DeviceDataManagerX11::GetInstance();
@@ skipping 76 matching lines @@
       y_offset_ordinal = &y_offset_ordinal_;
     if (!finger_count)
       finger_count = &finger_count_;
 
     DeviceDataManagerX11::GetInstance()->GetScrollOffsets(
         xev, x_offset, y_offset, x_offset_ordinal, y_offset_ordinal,
         finger_count);
     return true;
   }
 
-  if (DeviceDataManagerX11::GetInstance()->GetScrollClassDeviceDetail(xev) !=
+  if (DeviceDataManagerX11::GetInstance()->GetScrollClassEventDetail(xev) !=
       SCROLL_TYPE_NO_SCROLL) {
     double x_scroll_offset, y_scroll_offset;
     DeviceDataManagerX11::GetInstance()->GetScrollClassOffsets(
         xev, &x_scroll_offset, &y_scroll_offset);
     *x_offset = x_scroll_offset * kWheelScrollAmount;
     *y_offset = y_scroll_offset * kWheelScrollAmount;
     return true;
   }
   return false;
 }
@@ skipping 25 matching lines @@
                                                     vy_ordinal, is_cancel);
   return true;
 }
 
 void ResetTimestampRolloverCountersForTesting() {
   g_last_seen_timestamp_ms_ = 0;
   g_rollover_ms_ = 0;
 }
 
 }  // namespace ui