touchui: support XInput2 MT

views/touchui/touch_factory.h

 // Copyright (c) 2011 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.
 
 #ifndef VIEWS_TOUCHUI_TOUCH_FACTORY_H_
 #define VIEWS_TOUCHUI_TOUCH_FACTORY_H_
 #pragma once
 
 #include <bitset>
 #include <vector>
@@ skipping 24 matching lines @@
     // touch event, we need to determine which point triggered the event.
     // A touch point can have both a 'Slot ID' and a 'Tracking ID', and they can
     // be (in fact, usually are) different. The 'Slot ID' ranges between 0 and
     // (X - 1), where X is the maximum touch points supported by the device. The
     // 'Tracking ID' can be any 16-bit value. With XInput 2.0, an XI_Motion
     // event that comes from a currently-unused 'Slot ID' indicates the creation
     // of a new touch point, and any event that comes with a 0 value for
     // 'Tracking ID' marks the removal of a touch point. During the lifetime of
     // a touchpoint, we use the 'Slot ID' as its identifier. The XI_ButtonPress
     // and XI_ButtonRelease events are ignored.
+#if !defined(USE_XI2_MT)
     TP_SLOT_ID,           // ID of the finger that triggered a touch event
                           // (useful when tracking multiple simultaneous
                           // touches)
+#endif
+    // NOTE for XInput MT: 'Tracking ID' is provided in every touch event to
+    // track individual touch. 'Tracking ID' is an unsigned 32-bit value and
+    // is increased for each new touch. It will wrap back to 0 when reaching
+    // the numerical limit.
     TP_TRACKING_ID,       // ID of the touch point.
 
     TP_LAST_ENTRY
   };
 
   // Returns the TouchFactory singleton.
   static TouchFactory* GetInstance();
 
   // Updates the list of devices.
   void UpdateDeviceList(Display* display);
 
   // Checks whether an XI2 event should be processed or not (i.e. if the event
   // originated from a device we are interested in).
   bool ShouldProcessXI2Event(XEvent* xevent);
 
   // Setup an X Window for XInput2 events.
   void SetupXI2ForXWindow(::Window xid);
 
   // Keeps a list of touch devices so that it is possible to determine if a
   // pointer event is a touch-event or a mouse-event. The list is reset each
   // time this is called.
   void SetTouchDeviceList(const std::vector<unsigned int>& devices);
 
   // Is the device a touch-device?
   bool IsTouchDevice(unsigned int deviceid) const;
 
+#if !defined(USE_XI2_MT)
   // Is the slot ID currently used?
   bool IsSlotUsed(int slot) const;
 
   // Marks a slot as being used/unused.
   void SetSlotUsed(int slot, bool used);
+#endif
 
   // Grabs the touch devices for the specified window on the specified display.
   // Returns if grab was successful for all touch devices.
   bool GrabTouchDevices(Display* display, ::Window window);
 
   // Ungrabs the touch devices. Returns if ungrab was successful for all touch
   // devices.
   bool UngrabTouchDevices(Display* display);
 
   // Updates the root window to show (or hide) the cursor. Also indicate whether
@@ skipping 86 matching lines @@
   // index at the expense of space. If the kMaxDeviceNum grows larger that the
   // space waste becomes a concern, the 2D lookup table can be replaced by a
   // hash map.
   signed char valuator_lookup_[kMaxDeviceNum][TP_LAST_ENTRY];
 
   // Index table to find the min & max value of the TouchParam on a specific
   // device.
   int touch_param_min_[kMaxDeviceNum][TP_LAST_ENTRY];
   int touch_param_max_[kMaxDeviceNum][TP_LAST_ENTRY];
 
+#if !defined(USE_XI2_MT)
   // Maximum simultaneous touch points.
   static const int kMaxTouchPoints = 32;
 
   // A lookup table for slots in use for a touch event.
   std::bitset<kMaxTouchPoints> slots_used_;
+#endif
 
   DISALLOW_COPY_AND_ASSIGN(TouchFactory);
 };
 
 }  // namespace views
 
 #endif  // VIEWS_TOUCHUI_TOUCH_FACTORY_H_