commit 4815f2a6ada7941680b29581d5cf5a5ed168f618
author Jeff Brown <jeffbrown@google.com> Tue Apr 12 22:39:53 2011 -0700
committer Jeff Brown <jeffbrown@google.com> Tue Apr 19 15:35:51 2011 -0700
tree e0a613ac24a2edff88e1ee087bab4742bdf04d35
parent a01b1ff638352d3fa3a6d58481e018cda22b4c1c

Initial checkin of spot presentation for touchpad gestures.

Added a new PointerIcon API (hidden for now) for loading
pointer icons.

Fixed a starvation problem in the native Looper's sendMessage
implementation which caused new messages to be posted ahead
of old messages sent with sendMessageDelayed.

Redesigned the touch pad gestures to be defined in terms of
more fluid finger / spot movements.  The objective is to reinforce
the natural mapping between fingers and spots which means there
must not be any discontinuities in spot motion relative to
the fingers.

Removed the SpotController stub and folded its responsibilities
into PointerController.

Change-Id: I5126b1e69d95252fda7f2a684c9287e239a57163

include/ui/Input.h

diff --git a/include/ui/Input.h b/include/ui/Input.h
index 0dc29c8..9b92c73 100644
--- a/include/ui/Input.h
+++ b/include/ui/Input.h
@@ -620,6 +620,11 @@
     // Oldest sample to consider when calculating the velocity.
     static const nsecs_t MAX_AGE = 200 * 1000000; // 200 ms
 
+    // When the total duration of the window of samples being averaged is less
+    // than the window size, the resulting velocity is scaled to reduce the impact
+    // of overestimation in short traces.
+    static const nsecs_t MIN_WINDOW = 100 * 1000000; // 100 ms
+
     // The minimum duration between samples when estimating velocity.
     static const nsecs_t MIN_DURATION = 10 * 1000000; // 10 ms
 

libs/ui/Input.cpp

diff --git a/libs/ui/Input.cpp b/libs/ui/Input.cpp
index bbe579e..a95f432 100644
--- a/libs/ui/Input.cpp
+++ b/libs/ui/Input.cpp
@@ -832,6 +832,7 @@
         const Position& oldestPosition =
                 oldestMovement.positions[oldestMovement.idBits.getIndexOfBit(id)];
         nsecs_t lastDuration = 0;
+
         while (numTouches-- > 1) {
             if (++index == HISTORY_SIZE) {
                 index = 0;
@@ -858,6 +859,14 @@
 
         // Make sure we used at least one sample.
         if (samplesUsed != 0) {
+            // Scale the velocity linearly if the window of samples is small.
+            nsecs_t totalDuration = newestMovement.eventTime - oldestMovement.eventTime;
+            if (totalDuration < MIN_WINDOW) {
+                float scale = float(totalDuration) / float(MIN_WINDOW);
+                accumVx *= scale;
+                accumVy *= scale;
+            }
+
             *outVx = accumVx;
             *outVy = accumVy;
             return true;

libs/utils/Looper.cpp

diff --git a/libs/utils/Looper.cpp b/libs/utils/Looper.cpp
index d5dd126..b54fb9d 100644
--- a/libs/utils/Looper.cpp
+++ b/libs/utils/Looper.cpp
@@ -662,7 +662,8 @@
 #endif
 
 void Looper::sendMessage(const sp<MessageHandler>& handler, const Message& message) {
-    sendMessageAtTime(LLONG_MIN, handler, message);
+    nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
+    sendMessageAtTime(now, handler, message);
 }
 
 void Looper::sendMessageDelayed(nsecs_t uptimeDelay, const sp<MessageHandler>& handler,