Minor refactoring before starting on velocity tracker changes.
Bug: 6413587
Change-Id: I5eba2bb57193bff78cb3740de5f87aca0b31d154
diff --git a/core/java/android/view/VelocityTracker.java b/core/java/android/view/VelocityTracker.java
index 1c35e31..f703e34 100644
--- a/core/java/android/view/VelocityTracker.java
+++ b/core/java/android/view/VelocityTracker.java
@@ -298,6 +298,24 @@
return estimate(time, yCoeff);
}
+ /**
+ * Gets the X coefficient with the specified index.
+ * @param index The index of the coefficient to return.
+ * @return The X coefficient, or 0 if the index is greater than the degree.
+ */
+ public float getXCoeff(int index) {
+ return index <= degree ? xCoeff[index] : 0;
+ }
+
+ /**
+ * Gets the Y coefficient with the specified index.
+ * @param index The index of the coefficient to return.
+ * @return The Y coefficient, or 0 if the index is greater than the degree.
+ */
+ public float getYCoeff(int index) {
+ return index <= degree ? yCoeff[index] : 0;
+ }
+
private float estimate(float time, float[] c) {
float a = 0;
float scale = 1;
diff --git a/core/jni/android_view_VelocityTracker.cpp b/core/jni/android_view_VelocityTracker.cpp
index 668d3bb..04d1056 100644
--- a/core/jni/android_view_VelocityTracker.cpp
+++ b/core/jni/android_view_VelocityTracker.cpp
@@ -21,6 +21,7 @@
#include <android_runtime/AndroidRuntime.h>
#include <utils/Log.h>
#include <androidfw/Input.h>
+#include <androidfw/VelocityTracker.h>
#include "android_view_MotionEvent.h"
diff --git a/include/androidfw/Input.h b/include/androidfw/Input.h
index 6d03fd6..aa8b824 100644
--- a/include/androidfw/Input.h
+++ b/include/androidfw/Input.h
@@ -27,7 +27,6 @@
#include <utils/Timers.h>
#include <utils/RefBase.h>
#include <utils/String8.h>
-#include <utils/BitSet.h>
#ifdef HAVE_ANDROID_OS
class SkMatrix;
@@ -607,182 +606,6 @@
Vector<MotionEvent*> mMotionEventPool;
};
-/*
- * Calculates the velocity of pointer movements over time.
- */
-class VelocityTracker {
-public:
- // Default polynomial degree. (used by getVelocity)
- static const uint32_t DEFAULT_DEGREE = 2;
-
- // Default sample horizon. (used by getVelocity)
- // We don't use too much history by default since we want to react to quick
- // changes in direction.
- static const nsecs_t DEFAULT_HORIZON = 100 * 1000000; // 100 ms
-
- struct Position {
- float x, y;
- };
-
- struct Estimator {
- static const size_t MAX_DEGREE = 2;
-
- // Polynomial coefficients describing motion in X and Y.
- float xCoeff[MAX_DEGREE + 1], yCoeff[MAX_DEGREE + 1];
-
- // Polynomial degree (number of coefficients), or zero if no information is
- // available.
- uint32_t degree;
-
- // Confidence (coefficient of determination), between 0 (no fit) and 1 (perfect fit).
- float confidence;
-
- inline void clear() {
- degree = 0;
- confidence = 0;
- for (size_t i = 0; i <= MAX_DEGREE; i++) {
- xCoeff[i] = 0;
- yCoeff[i] = 0;
- }
- }
- };
-
- VelocityTracker();
-
- // Resets the velocity tracker state.
- void clear();
-
- // Resets the velocity tracker state for specific pointers.
- // Call this method when some pointers have changed and may be reusing
- // an id that was assigned to a different pointer earlier.
- void clearPointers(BitSet32 idBits);
-
- // Adds movement information for a set of pointers.
- // The idBits bitfield specifies the pointer ids of the pointers whose positions
- // are included in the movement.
- // The positions array contains position information for each pointer in order by
- // increasing id. Its size should be equal to the number of one bits in idBits.
- void addMovement(nsecs_t eventTime, BitSet32 idBits, const Position* positions);
-
- // Adds movement information for all pointers in a MotionEvent, including historical samples.
- void addMovement(const MotionEvent* event);
-
- // Gets the velocity of the specified pointer id in position units per second.
- // Returns false and sets the velocity components to zero if there is
- // insufficient movement information for the pointer.
- bool getVelocity(uint32_t id, float* outVx, float* outVy) const;
-
- // Gets a quadratic estimator for the movements of the specified pointer id.
- // Returns false and clears the estimator if there is no information available
- // about the pointer.
- bool getEstimator(uint32_t id, uint32_t degree, nsecs_t horizon,
- Estimator* outEstimator) const;
-
- // Gets the active pointer id, or -1 if none.
- inline int32_t getActivePointerId() const { return mActivePointerId; }
-
- // Gets a bitset containing all pointer ids from the most recent movement.
- inline BitSet32 getCurrentPointerIdBits() const { return mMovements[mIndex].idBits; }
-
-private:
- // Number of samples to keep.
- static const uint32_t HISTORY_SIZE = 20;
-
- struct Movement {
- nsecs_t eventTime;
- BitSet32 idBits;
- Position positions[MAX_POINTERS];
-
- inline const Position& getPosition(uint32_t id) const {
- return positions[idBits.getIndexOfBit(id)];
- }
- };
-
- uint32_t mIndex;
- Movement mMovements[HISTORY_SIZE];
- int32_t mActivePointerId;
-};
-
-
-/*
- * Specifies parameters that govern pointer or wheel acceleration.
- */
-struct VelocityControlParameters {
- // A scale factor that is multiplied with the raw velocity deltas
- // prior to applying any other velocity control factors. The scale
- // factor should be used to adapt the input device resolution
- // (eg. counts per inch) to the output device resolution (eg. pixels per inch).
- //
- // Must be a positive value.
- // Default is 1.0 (no scaling).
- float scale;
-
- // The scaled speed at which acceleration begins to be applied.
- // This value establishes the upper bound of a low speed regime for
- // small precise motions that are performed without any acceleration.
- //
- // Must be a non-negative value.
- // Default is 0.0 (no low threshold).
- float lowThreshold;
-
- // The scaled speed at which maximum acceleration is applied.
- // The difference between highThreshold and lowThreshold controls
- // the range of speeds over which the acceleration factor is interpolated.
- // The wider the range, the smoother the acceleration.
- //
- // Must be a non-negative value greater than or equal to lowThreshold.
- // Default is 0.0 (no high threshold).
- float highThreshold;
-
- // The acceleration factor.
- // When the speed is above the low speed threshold, the velocity will scaled
- // by an interpolated value between 1.0 and this amount.
- //
- // Must be a positive greater than or equal to 1.0.
- // Default is 1.0 (no acceleration).
- float acceleration;
-
- VelocityControlParameters() :
- scale(1.0f), lowThreshold(0.0f), highThreshold(0.0f), acceleration(1.0f) {
- }
-
- VelocityControlParameters(float scale, float lowThreshold,
- float highThreshold, float acceleration) :
- scale(scale), lowThreshold(lowThreshold),
- highThreshold(highThreshold), acceleration(acceleration) {
- }
-};
-
-/*
- * Implements mouse pointer and wheel speed control and acceleration.
- */
-class VelocityControl {
-public:
- VelocityControl();
-
- /* Sets the various parameters. */
- void setParameters(const VelocityControlParameters& parameters);
-
- /* Resets the current movement counters to zero.
- * This has the effect of nullifying any acceleration. */
- void reset();
-
- /* Translates a raw movement delta into an appropriately
- * scaled / accelerated delta based on the current velocity. */
- void move(nsecs_t eventTime, float* deltaX, float* deltaY);
-
-private:
- // If no movements are received within this amount of time,
- // we assume the movement has stopped and reset the movement counters.
- static const nsecs_t STOP_TIME = 500 * 1000000; // 500 ms
-
- VelocityControlParameters mParameters;
-
- nsecs_t mLastMovementTime;
- VelocityTracker::Position mRawPosition;
- VelocityTracker mVelocityTracker;
-};
-
} // namespace android
#endif // _ANDROIDFW_INPUT_H
diff --git a/include/androidfw/VelocityControl.h b/include/androidfw/VelocityControl.h
new file mode 100644
index 0000000..84e0444
--- /dev/null
+++ b/include/androidfw/VelocityControl.h
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _ANDROIDFW_VELOCITY_CONTROL_H
+#define _ANDROIDFW_VELOCITY_CONTROL_H
+
+#include <androidfw/Input.h>
+#include <androidfw/VelocityTracker.h>
+#include <utils/Timers.h>
+
+namespace android {
+
+/*
+ * Specifies parameters that govern pointer or wheel acceleration.
+ */
+struct VelocityControlParameters {
+ // A scale factor that is multiplied with the raw velocity deltas
+ // prior to applying any other velocity control factors. The scale
+ // factor should be used to adapt the input device resolution
+ // (eg. counts per inch) to the output device resolution (eg. pixels per inch).
+ //
+ // Must be a positive value.
+ // Default is 1.0 (no scaling).
+ float scale;
+
+ // The scaled speed at which acceleration begins to be applied.
+ // This value establishes the upper bound of a low speed regime for
+ // small precise motions that are performed without any acceleration.
+ //
+ // Must be a non-negative value.
+ // Default is 0.0 (no low threshold).
+ float lowThreshold;
+
+ // The scaled speed at which maximum acceleration is applied.
+ // The difference between highThreshold and lowThreshold controls
+ // the range of speeds over which the acceleration factor is interpolated.
+ // The wider the range, the smoother the acceleration.
+ //
+ // Must be a non-negative value greater than or equal to lowThreshold.
+ // Default is 0.0 (no high threshold).
+ float highThreshold;
+
+ // The acceleration factor.
+ // When the speed is above the low speed threshold, the velocity will scaled
+ // by an interpolated value between 1.0 and this amount.
+ //
+ // Must be a positive greater than or equal to 1.0.
+ // Default is 1.0 (no acceleration).
+ float acceleration;
+
+ VelocityControlParameters() :
+ scale(1.0f), lowThreshold(0.0f), highThreshold(0.0f), acceleration(1.0f) {
+ }
+
+ VelocityControlParameters(float scale, float lowThreshold,
+ float highThreshold, float acceleration) :
+ scale(scale), lowThreshold(lowThreshold),
+ highThreshold(highThreshold), acceleration(acceleration) {
+ }
+};
+
+/*
+ * Implements mouse pointer and wheel speed control and acceleration.
+ */
+class VelocityControl {
+public:
+ VelocityControl();
+
+ /* Sets the various parameters. */
+ void setParameters(const VelocityControlParameters& parameters);
+
+ /* Resets the current movement counters to zero.
+ * This has the effect of nullifying any acceleration. */
+ void reset();
+
+ /* Translates a raw movement delta into an appropriately
+ * scaled / accelerated delta based on the current velocity. */
+ void move(nsecs_t eventTime, float* deltaX, float* deltaY);
+
+private:
+ // If no movements are received within this amount of time,
+ // we assume the movement has stopped and reset the movement counters.
+ static const nsecs_t STOP_TIME = 500 * 1000000; // 500 ms
+
+ VelocityControlParameters mParameters;
+
+ nsecs_t mLastMovementTime;
+ VelocityTracker::Position mRawPosition;
+ VelocityTracker mVelocityTracker;
+};
+
+} // namespace android
+
+#endif // _ANDROIDFW_VELOCITY_CONTROL_H
diff --git a/include/androidfw/VelocityTracker.h b/include/androidfw/VelocityTracker.h
new file mode 100644
index 0000000..6d17e1f
--- /dev/null
+++ b/include/androidfw/VelocityTracker.h
@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _ANDROIDFW_VELOCITY_TRACKER_H
+#define _ANDROIDFW_VELOCITY_TRACKER_H
+
+#include <androidfw/Input.h>
+#include <utils/Timers.h>
+#include <utils/BitSet.h>
+
+namespace android {
+
+/*
+ * Calculates the velocity of pointer movements over time.
+ */
+class VelocityTracker {
+public:
+ // Default polynomial degree. (used by getVelocity)
+ static const uint32_t DEFAULT_DEGREE = 2;
+
+ // Default sample horizon. (used by getVelocity)
+ // We don't use too much history by default since we want to react to quick
+ // changes in direction.
+ static const nsecs_t DEFAULT_HORIZON = 100 * 1000000; // 100 ms
+
+ struct Position {
+ float x, y;
+ };
+
+ struct Estimator {
+ static const size_t MAX_DEGREE = 2;
+
+ // Polynomial coefficients describing motion in X and Y.
+ float xCoeff[MAX_DEGREE + 1], yCoeff[MAX_DEGREE + 1];
+
+ // Polynomial degree (number of coefficients), or zero if no information is
+ // available.
+ uint32_t degree;
+
+ // Confidence (coefficient of determination), between 0 (no fit) and 1 (perfect fit).
+ float confidence;
+
+ inline void clear() {
+ degree = 0;
+ confidence = 0;
+ for (size_t i = 0; i <= MAX_DEGREE; i++) {
+ xCoeff[i] = 0;
+ yCoeff[i] = 0;
+ }
+ }
+ };
+
+ VelocityTracker();
+
+ // Resets the velocity tracker state.
+ void clear();
+
+ // Resets the velocity tracker state for specific pointers.
+ // Call this method when some pointers have changed and may be reusing
+ // an id that was assigned to a different pointer earlier.
+ void clearPointers(BitSet32 idBits);
+
+ // Adds movement information for a set of pointers.
+ // The idBits bitfield specifies the pointer ids of the pointers whose positions
+ // are included in the movement.
+ // The positions array contains position information for each pointer in order by
+ // increasing id. Its size should be equal to the number of one bits in idBits.
+ void addMovement(nsecs_t eventTime, BitSet32 idBits, const Position* positions);
+
+ // Adds movement information for all pointers in a MotionEvent, including historical samples.
+ void addMovement(const MotionEvent* event);
+
+ // Gets the velocity of the specified pointer id in position units per second.
+ // Returns false and sets the velocity components to zero if there is
+ // insufficient movement information for the pointer.
+ bool getVelocity(uint32_t id, float* outVx, float* outVy) const;
+
+ // Gets a quadratic estimator for the movements of the specified pointer id.
+ // Returns false and clears the estimator if there is no information available
+ // about the pointer.
+ bool getEstimator(uint32_t id, uint32_t degree, nsecs_t horizon,
+ Estimator* outEstimator) const;
+
+ // Gets the active pointer id, or -1 if none.
+ inline int32_t getActivePointerId() const { return mActivePointerId; }
+
+ // Gets a bitset containing all pointer ids from the most recent movement.
+ inline BitSet32 getCurrentPointerIdBits() const { return mMovements[mIndex].idBits; }
+
+private:
+ // Number of samples to keep.
+ static const uint32_t HISTORY_SIZE = 20;
+
+ struct Movement {
+ nsecs_t eventTime;
+ BitSet32 idBits;
+ Position positions[MAX_POINTERS];
+
+ inline const Position& getPosition(uint32_t id) const {
+ return positions[idBits.getIndexOfBit(id)];
+ }
+ };
+
+ uint32_t mIndex;
+ Movement mMovements[HISTORY_SIZE];
+ int32_t mActivePointerId;
+};
+
+} // namespace android
+
+#endif // _ANDROIDFW_VELOCITY_TRACKER_H
diff --git a/libs/androidfw/Android.mk b/libs/androidfw/Android.mk
index 95c77d4..3ed75a2 100644
--- a/libs/androidfw/Android.mk
+++ b/libs/androidfw/Android.mk
@@ -33,6 +33,8 @@
Keyboard.cpp \
KeyCharacterMap.cpp \
KeyLayoutMap.cpp \
+ VelocityControl.cpp \
+ VelocityTracker.cpp \
VirtualKeyMap.cpp
commonSources:= \
diff --git a/libs/androidfw/Input.cpp b/libs/androidfw/Input.cpp
index fbe1926..40a6c47 100644
--- a/libs/androidfw/Input.cpp
+++ b/libs/androidfw/Input.cpp
@@ -15,31 +15,13 @@
*/
#define LOG_TAG "Input"
-
//#define LOG_NDEBUG 0
-// Log debug messages about keymap probing.
-#define DEBUG_PROBE 0
-
-// Log debug messages about velocity tracking.
-#define DEBUG_VELOCITY 0
-
-// Log debug messages about least squares fitting.
-#define DEBUG_LEAST_SQUARES 0
-
-// Log debug messages about acceleration.
-#define DEBUG_ACCELERATION 0
-
-
-#include <stdlib.h>
-#include <unistd.h>
-#include <ctype.h>
-
-#include <androidfw/Input.h>
-
#include <math.h>
#include <limits.h>
+#include <androidfw/Input.h>
+
#ifdef HAVE_ANDROID_OS
#include <binder/Parcel.h>
@@ -665,492 +647,4 @@
delete event;
}
-
-// --- VelocityTracker ---
-
-const uint32_t VelocityTracker::DEFAULT_DEGREE;
-const nsecs_t VelocityTracker::DEFAULT_HORIZON;
-const uint32_t VelocityTracker::HISTORY_SIZE;
-
-static inline float vectorDot(const float* a, const float* b, uint32_t m) {
- float r = 0;
- while (m--) {
- r += *(a++) * *(b++);
- }
- return r;
-}
-
-static inline float vectorNorm(const float* a, uint32_t m) {
- float r = 0;
- while (m--) {
- float t = *(a++);
- r += t * t;
- }
- return sqrtf(r);
-}
-
-#if DEBUG_LEAST_SQUARES || DEBUG_VELOCITY
-static String8 vectorToString(const float* a, uint32_t m) {
- String8 str;
- str.append("[");
- while (m--) {
- str.appendFormat(" %f", *(a++));
- if (m) {
- str.append(",");
- }
- }
- str.append(" ]");
- return str;
-}
-
-static String8 matrixToString(const float* a, uint32_t m, uint32_t n, bool rowMajor) {
- String8 str;
- str.append("[");
- for (size_t i = 0; i < m; i++) {
- if (i) {
- str.append(",");
- }
- str.append(" [");
- for (size_t j = 0; j < n; j++) {
- if (j) {
- str.append(",");
- }
- str.appendFormat(" %f", a[rowMajor ? i * n + j : j * m + i]);
- }
- str.append(" ]");
- }
- str.append(" ]");
- return str;
-}
-#endif
-
-VelocityTracker::VelocityTracker() {
- clear();
-}
-
-void VelocityTracker::clear() {
- mIndex = 0;
- mMovements[0].idBits.clear();
- mActivePointerId = -1;
-}
-
-void VelocityTracker::clearPointers(BitSet32 idBits) {
- BitSet32 remainingIdBits(mMovements[mIndex].idBits.value & ~idBits.value);
- mMovements[mIndex].idBits = remainingIdBits;
-
- if (mActivePointerId >= 0 && idBits.hasBit(mActivePointerId)) {
- mActivePointerId = !remainingIdBits.isEmpty() ? remainingIdBits.firstMarkedBit() : -1;
- }
-}
-
-void VelocityTracker::addMovement(nsecs_t eventTime, BitSet32 idBits, const Position* positions) {
- if (++mIndex == HISTORY_SIZE) {
- mIndex = 0;
- }
-
- while (idBits.count() > MAX_POINTERS) {
- idBits.clearLastMarkedBit();
- }
-
- Movement& movement = mMovements[mIndex];
- movement.eventTime = eventTime;
- movement.idBits = idBits;
- uint32_t count = idBits.count();
- for (uint32_t i = 0; i < count; i++) {
- movement.positions[i] = positions[i];
- }
-
- if (mActivePointerId < 0 || !idBits.hasBit(mActivePointerId)) {
- mActivePointerId = count != 0 ? idBits.firstMarkedBit() : -1;
- }
-
-#if DEBUG_VELOCITY
- ALOGD("VelocityTracker: addMovement eventTime=%lld, idBits=0x%08x, activePointerId=%d",
- eventTime, idBits.value, mActivePointerId);
- for (BitSet32 iterBits(idBits); !iterBits.isEmpty(); ) {
- uint32_t id = iterBits.firstMarkedBit();
- uint32_t index = idBits.getIndexOfBit(id);
- iterBits.clearBit(id);
- Estimator estimator;
- getEstimator(id, DEFAULT_DEGREE, DEFAULT_HORIZON, &estimator);
- ALOGD(" %d: position (%0.3f, %0.3f), "
- "estimator (degree=%d, xCoeff=%s, yCoeff=%s, confidence=%f)",
- id, positions[index].x, positions[index].y,
- int(estimator.degree),
- vectorToString(estimator.xCoeff, estimator.degree).string(),
- vectorToString(estimator.yCoeff, estimator.degree).string(),
- estimator.confidence);
- }
-#endif
-}
-
-void VelocityTracker::addMovement(const MotionEvent* event) {
- int32_t actionMasked = event->getActionMasked();
-
- switch (actionMasked) {
- case AMOTION_EVENT_ACTION_DOWN:
- case AMOTION_EVENT_ACTION_HOVER_ENTER:
- // Clear all pointers on down before adding the new movement.
- clear();
- break;
- case AMOTION_EVENT_ACTION_POINTER_DOWN: {
- // Start a new movement trace for a pointer that just went down.
- // We do this on down instead of on up because the client may want to query the
- // final velocity for a pointer that just went up.
- BitSet32 downIdBits;
- downIdBits.markBit(event->getPointerId(event->getActionIndex()));
- clearPointers(downIdBits);
- break;
- }
- case AMOTION_EVENT_ACTION_MOVE:
- case AMOTION_EVENT_ACTION_HOVER_MOVE:
- break;
- default:
- // Ignore all other actions because they do not convey any new information about
- // pointer movement. We also want to preserve the last known velocity of the pointers.
- // Note that ACTION_UP and ACTION_POINTER_UP always report the last known position
- // of the pointers that went up. ACTION_POINTER_UP does include the new position of
- // pointers that remained down but we will also receive an ACTION_MOVE with this
- // information if any of them actually moved. Since we don't know how many pointers
- // will be going up at once it makes sense to just wait for the following ACTION_MOVE
- // before adding the movement.
- return;
- }
-
- size_t pointerCount = event->getPointerCount();
- if (pointerCount > MAX_POINTERS) {
- pointerCount = MAX_POINTERS;
- }
-
- BitSet32 idBits;
- for (size_t i = 0; i < pointerCount; i++) {
- idBits.markBit(event->getPointerId(i));
- }
-
- nsecs_t eventTime;
- Position positions[pointerCount];
-
- size_t historySize = event->getHistorySize();
- for (size_t h = 0; h < historySize; h++) {
- eventTime = event->getHistoricalEventTime(h);
- for (size_t i = 0; i < pointerCount; i++) {
- positions[i].x = event->getHistoricalX(i, h);
- positions[i].y = event->getHistoricalY(i, h);
- }
- addMovement(eventTime, idBits, positions);
- }
-
- eventTime = event->getEventTime();
- for (size_t i = 0; i < pointerCount; i++) {
- positions[i].x = event->getX(i);
- positions[i].y = event->getY(i);
- }
- addMovement(eventTime, idBits, positions);
-}
-
-/**
- * Solves a linear least squares problem to obtain a N degree polynomial that fits
- * the specified input data as nearly as possible.
- *
- * Returns true if a solution is found, false otherwise.
- *
- * The input consists of two vectors of data points X and Y with indices 0..m-1.
- * The output is a vector B with indices 0..n-1 that describes a polynomial
- * that fits the data, such the sum of abs(Y[i] - (B[0] + B[1] X[i] + B[2] X[i]^2 ... B[n] X[i]^n))
- * for all i between 0 and m-1 is minimized.
- *
- * That is to say, the function that generated the input data can be approximated
- * by y(x) ~= B[0] + B[1] x + B[2] x^2 + ... + B[n] x^n.
- *
- * The coefficient of determination (R^2) is also returned to describe the goodness
- * of fit of the model for the given data. It is a value between 0 and 1, where 1
- * indicates perfect correspondence.
- *
- * This function first expands the X vector to a m by n matrix A such that
- * A[i][0] = 1, A[i][1] = X[i], A[i][2] = X[i]^2, ..., A[i][n] = X[i]^n.
- *
- * Then it calculates the QR decomposition of A yielding an m by m orthonormal matrix Q
- * and an m by n upper triangular matrix R. Because R is upper triangular (lower
- * part is all zeroes), we can simplify the decomposition into an m by n matrix
- * Q1 and a n by n matrix R1 such that A = Q1 R1.
- *
- * Finally we solve the system of linear equations given by R1 B = (Qtranspose Y)
- * to find B.
- *
- * For efficiency, we lay out A and Q column-wise in memory because we frequently
- * operate on the column vectors. Conversely, we lay out R row-wise.
- *
- * http://en.wikipedia.org/wiki/Numerical_methods_for_linear_least_squares
- * http://en.wikipedia.org/wiki/Gram-Schmidt
- */
-static bool solveLeastSquares(const float* x, const float* y, uint32_t m, uint32_t n,
- float* outB, float* outDet) {
-#if DEBUG_LEAST_SQUARES
- ALOGD("solveLeastSquares: m=%d, n=%d, x=%s, y=%s", int(m), int(n),
- vectorToString(x, m).string(), vectorToString(y, m).string());
-#endif
-
- // Expand the X vector to a matrix A.
- float a[n][m]; // column-major order
- for (uint32_t h = 0; h < m; h++) {
- a[0][h] = 1;
- for (uint32_t i = 1; i < n; i++) {
- a[i][h] = a[i - 1][h] * x[h];
- }
- }
-#if DEBUG_LEAST_SQUARES
- ALOGD(" - a=%s", matrixToString(&a[0][0], m, n, false /*rowMajor*/).string());
-#endif
-
- // Apply the Gram-Schmidt process to A to obtain its QR decomposition.
- float q[n][m]; // orthonormal basis, column-major order
- float r[n][n]; // upper triangular matrix, row-major order
- for (uint32_t j = 0; j < n; j++) {
- for (uint32_t h = 0; h < m; h++) {
- q[j][h] = a[j][h];
- }
- for (uint32_t i = 0; i < j; i++) {
- float dot = vectorDot(&q[j][0], &q[i][0], m);
- for (uint32_t h = 0; h < m; h++) {
- q[j][h] -= dot * q[i][h];
- }
- }
-
- float norm = vectorNorm(&q[j][0], m);
- if (norm < 0.000001f) {
- // vectors are linearly dependent or zero so no solution
-#if DEBUG_LEAST_SQUARES
- ALOGD(" - no solution, norm=%f", norm);
-#endif
- return false;
- }
-
- float invNorm = 1.0f / norm;
- for (uint32_t h = 0; h < m; h++) {
- q[j][h] *= invNorm;
- }
- for (uint32_t i = 0; i < n; i++) {
- r[j][i] = i < j ? 0 : vectorDot(&q[j][0], &a[i][0], m);
- }
- }
-#if DEBUG_LEAST_SQUARES
- ALOGD(" - q=%s", matrixToString(&q[0][0], m, n, false /*rowMajor*/).string());
- ALOGD(" - r=%s", matrixToString(&r[0][0], n, n, true /*rowMajor*/).string());
-
- // calculate QR, if we factored A correctly then QR should equal A
- float qr[n][m];
- for (uint32_t h = 0; h < m; h++) {
- for (uint32_t i = 0; i < n; i++) {
- qr[i][h] = 0;
- for (uint32_t j = 0; j < n; j++) {
- qr[i][h] += q[j][h] * r[j][i];
- }
- }
- }
- ALOGD(" - qr=%s", matrixToString(&qr[0][0], m, n, false /*rowMajor*/).string());
-#endif
-
- // Solve R B = Qt Y to find B. This is easy because R is upper triangular.
- // We just work from bottom-right to top-left calculating B's coefficients.
- for (uint32_t i = n; i-- != 0; ) {
- outB[i] = vectorDot(&q[i][0], y, m);
- for (uint32_t j = n - 1; j > i; j--) {
- outB[i] -= r[i][j] * outB[j];
- }
- outB[i] /= r[i][i];
- }
-#if DEBUG_LEAST_SQUARES
- ALOGD(" - b=%s", vectorToString(outB, n).string());
-#endif
-
- // Calculate the coefficient of determination as 1 - (SSerr / SStot) where
- // SSerr is the residual sum of squares (squared variance of the error),
- // and SStot is the total sum of squares (squared variance of the data).
- float ymean = 0;
- for (uint32_t h = 0; h < m; h++) {
- ymean += y[h];
- }
- ymean /= m;
-
- float sserr = 0;
- float sstot = 0;
- for (uint32_t h = 0; h < m; h++) {
- float err = y[h] - outB[0];
- float term = 1;
- for (uint32_t i = 1; i < n; i++) {
- term *= x[h];
- err -= term * outB[i];
- }
- sserr += err * err;
- float var = y[h] - ymean;
- sstot += var * var;
- }
- *outDet = sstot > 0.000001f ? 1.0f - (sserr / sstot) : 1;
-#if DEBUG_LEAST_SQUARES
- ALOGD(" - sserr=%f", sserr);
- ALOGD(" - sstot=%f", sstot);
- ALOGD(" - det=%f", *outDet);
-#endif
- return true;
-}
-
-bool VelocityTracker::getVelocity(uint32_t id, float* outVx, float* outVy) const {
- Estimator estimator;
- if (getEstimator(id, DEFAULT_DEGREE, DEFAULT_HORIZON, &estimator)) {
- if (estimator.degree >= 1) {
- *outVx = estimator.xCoeff[1];
- *outVy = estimator.yCoeff[1];
- return true;
- }
- }
- *outVx = 0;
- *outVy = 0;
- return false;
-}
-
-bool VelocityTracker::getEstimator(uint32_t id, uint32_t degree, nsecs_t horizon,
- Estimator* outEstimator) const {
- outEstimator->clear();
-
- // Iterate over movement samples in reverse time order and collect samples.
- float x[HISTORY_SIZE];
- float y[HISTORY_SIZE];
- float time[HISTORY_SIZE];
- uint32_t m = 0;
- uint32_t index = mIndex;
- const Movement& newestMovement = mMovements[mIndex];
- do {
- const Movement& movement = mMovements[index];
- if (!movement.idBits.hasBit(id)) {
- break;
- }
-
- nsecs_t age = newestMovement.eventTime - movement.eventTime;
- if (age > horizon) {
- break;
- }
-
- const Position& position = movement.getPosition(id);
- x[m] = position.x;
- y[m] = position.y;
- time[m] = -age * 0.000000001f;
- index = (index == 0 ? HISTORY_SIZE : index) - 1;
- } while (++m < HISTORY_SIZE);
-
- if (m == 0) {
- return false; // no data
- }
-
- // Calculate a least squares polynomial fit.
- if (degree > Estimator::MAX_DEGREE) {
- degree = Estimator::MAX_DEGREE;
- }
- if (degree > m - 1) {
- degree = m - 1;
- }
- if (degree >= 1) {
- float xdet, ydet;
- uint32_t n = degree + 1;
- if (solveLeastSquares(time, x, m, n, outEstimator->xCoeff, &xdet)
- && solveLeastSquares(time, y, m, n, outEstimator->yCoeff, &ydet)) {
- outEstimator->degree = degree;
- outEstimator->confidence = xdet * ydet;
-#if DEBUG_LEAST_SQUARES
- ALOGD("estimate: degree=%d, xCoeff=%s, yCoeff=%s, confidence=%f",
- int(outEstimator->degree),
- vectorToString(outEstimator->xCoeff, n).string(),
- vectorToString(outEstimator->yCoeff, n).string(),
- outEstimator->confidence);
-#endif
- return true;
- }
- }
-
- // No velocity data available for this pointer, but we do have its current position.
- outEstimator->xCoeff[0] = x[0];
- outEstimator->yCoeff[0] = y[0];
- outEstimator->degree = 0;
- outEstimator->confidence = 1;
- return true;
-}
-
-
-// --- VelocityControl ---
-
-const nsecs_t VelocityControl::STOP_TIME;
-
-VelocityControl::VelocityControl() {
- reset();
-}
-
-void VelocityControl::setParameters(const VelocityControlParameters& parameters) {
- mParameters = parameters;
- reset();
-}
-
-void VelocityControl::reset() {
- mLastMovementTime = LLONG_MIN;
- mRawPosition.x = 0;
- mRawPosition.y = 0;
- mVelocityTracker.clear();
-}
-
-void VelocityControl::move(nsecs_t eventTime, float* deltaX, float* deltaY) {
- if ((deltaX && *deltaX) || (deltaY && *deltaY)) {
- if (eventTime >= mLastMovementTime + STOP_TIME) {
-#if DEBUG_ACCELERATION
- ALOGD("VelocityControl: stopped, last movement was %0.3fms ago",
- (eventTime - mLastMovementTime) * 0.000001f);
-#endif
- reset();
- }
-
- mLastMovementTime = eventTime;
- if (deltaX) {
- mRawPosition.x += *deltaX;
- }
- if (deltaY) {
- mRawPosition.y += *deltaY;
- }
- mVelocityTracker.addMovement(eventTime, BitSet32(BitSet32::valueForBit(0)), &mRawPosition);
-
- float vx, vy;
- float scale = mParameters.scale;
- if (mVelocityTracker.getVelocity(0, &vx, &vy)) {
- float speed = hypotf(vx, vy) * scale;
- if (speed >= mParameters.highThreshold) {
- // Apply full acceleration above the high speed threshold.
- scale *= mParameters.acceleration;
- } else if (speed > mParameters.lowThreshold) {
- // Linearly interpolate the acceleration to apply between the low and high
- // speed thresholds.
- scale *= 1 + (speed - mParameters.lowThreshold)
- / (mParameters.highThreshold - mParameters.lowThreshold)
- * (mParameters.acceleration - 1);
- }
-
-#if DEBUG_ACCELERATION
- ALOGD("VelocityControl(%0.3f, %0.3f, %0.3f, %0.3f): "
- "vx=%0.3f, vy=%0.3f, speed=%0.3f, accel=%0.3f",
- mParameters.scale, mParameters.lowThreshold, mParameters.highThreshold,
- mParameters.acceleration,
- vx, vy, speed, scale / mParameters.scale);
-#endif
- } else {
-#if DEBUG_ACCELERATION
- ALOGD("VelocityControl(%0.3f, %0.3f, %0.3f, %0.3f): unknown velocity",
- mParameters.scale, mParameters.lowThreshold, mParameters.highThreshold,
- mParameters.acceleration);
-#endif
- }
-
- if (deltaX) {
- *deltaX *= scale;
- }
- if (deltaY) {
- *deltaY *= scale;
- }
- }
-}
-
} // namespace android
diff --git a/libs/androidfw/VelocityControl.cpp b/libs/androidfw/VelocityControl.cpp
new file mode 100644
index 0000000..cde2b76
--- /dev/null
+++ b/libs/androidfw/VelocityControl.cpp
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "VelocityControl"
+//#define LOG_NDEBUG 0
+
+// Log debug messages about acceleration.
+#define DEBUG_ACCELERATION 0
+
+#include <math.h>
+#include <limits.h>
+
+#include <androidfw/VelocityControl.h>
+#include <utils/BitSet.h>
+#include <utils/Timers.h>
+
+namespace android {
+
+// --- VelocityControl ---
+
+const nsecs_t VelocityControl::STOP_TIME;
+
+VelocityControl::VelocityControl() {
+ reset();
+}
+
+void VelocityControl::setParameters(const VelocityControlParameters& parameters) {
+ mParameters = parameters;
+ reset();
+}
+
+void VelocityControl::reset() {
+ mLastMovementTime = LLONG_MIN;
+ mRawPosition.x = 0;
+ mRawPosition.y = 0;
+ mVelocityTracker.clear();
+}
+
+void VelocityControl::move(nsecs_t eventTime, float* deltaX, float* deltaY) {
+ if ((deltaX && *deltaX) || (deltaY && *deltaY)) {
+ if (eventTime >= mLastMovementTime + STOP_TIME) {
+#if DEBUG_ACCELERATION
+ ALOGD("VelocityControl: stopped, last movement was %0.3fms ago",
+ (eventTime - mLastMovementTime) * 0.000001f);
+#endif
+ reset();
+ }
+
+ mLastMovementTime = eventTime;
+ if (deltaX) {
+ mRawPosition.x += *deltaX;
+ }
+ if (deltaY) {
+ mRawPosition.y += *deltaY;
+ }
+ mVelocityTracker.addMovement(eventTime, BitSet32(BitSet32::valueForBit(0)), &mRawPosition);
+
+ float vx, vy;
+ float scale = mParameters.scale;
+ if (mVelocityTracker.getVelocity(0, &vx, &vy)) {
+ float speed = hypotf(vx, vy) * scale;
+ if (speed >= mParameters.highThreshold) {
+ // Apply full acceleration above the high speed threshold.
+ scale *= mParameters.acceleration;
+ } else if (speed > mParameters.lowThreshold) {
+ // Linearly interpolate the acceleration to apply between the low and high
+ // speed thresholds.
+ scale *= 1 + (speed - mParameters.lowThreshold)
+ / (mParameters.highThreshold - mParameters.lowThreshold)
+ * (mParameters.acceleration - 1);
+ }
+
+#if DEBUG_ACCELERATION
+ ALOGD("VelocityControl(%0.3f, %0.3f, %0.3f, %0.3f): "
+ "vx=%0.3f, vy=%0.3f, speed=%0.3f, accel=%0.3f",
+ mParameters.scale, mParameters.lowThreshold, mParameters.highThreshold,
+ mParameters.acceleration,
+ vx, vy, speed, scale / mParameters.scale);
+#endif
+ } else {
+#if DEBUG_ACCELERATION
+ ALOGD("VelocityControl(%0.3f, %0.3f, %0.3f, %0.3f): unknown velocity",
+ mParameters.scale, mParameters.lowThreshold, mParameters.highThreshold,
+ mParameters.acceleration);
+#endif
+ }
+
+ if (deltaX) {
+ *deltaX *= scale;
+ }
+ if (deltaY) {
+ *deltaY *= scale;
+ }
+ }
+}
+
+} // namespace android
diff --git a/libs/androidfw/VelocityTracker.cpp b/libs/androidfw/VelocityTracker.cpp
new file mode 100644
index 0000000..2fb094e
--- /dev/null
+++ b/libs/androidfw/VelocityTracker.cpp
@@ -0,0 +1,444 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "VelocityTracker"
+//#define LOG_NDEBUG 0
+
+// Log debug messages about velocity tracking.
+#define DEBUG_VELOCITY 0
+
+// Log debug messages about least squares fitting.
+#define DEBUG_LEAST_SQUARES 0
+
+#include <math.h>
+#include <limits.h>
+
+#include <androidfw/VelocityTracker.h>
+#include <utils/BitSet.h>
+#include <utils/String8.h>
+#include <utils/Timers.h>
+
+namespace android {
+
+// --- VelocityTracker ---
+
+const uint32_t VelocityTracker::DEFAULT_DEGREE;
+const nsecs_t VelocityTracker::DEFAULT_HORIZON;
+const uint32_t VelocityTracker::HISTORY_SIZE;
+
+static inline float vectorDot(const float* a, const float* b, uint32_t m) {
+ float r = 0;
+ while (m--) {
+ r += *(a++) * *(b++);
+ }
+ return r;
+}
+
+static inline float vectorNorm(const float* a, uint32_t m) {
+ float r = 0;
+ while (m--) {
+ float t = *(a++);
+ r += t * t;
+ }
+ return sqrtf(r);
+}
+
+#if DEBUG_LEAST_SQUARES || DEBUG_VELOCITY
+static String8 vectorToString(const float* a, uint32_t m) {
+ String8 str;
+ str.append("[");
+ while (m--) {
+ str.appendFormat(" %f", *(a++));
+ if (m) {
+ str.append(",");
+ }
+ }
+ str.append(" ]");
+ return str;
+}
+
+static String8 matrixToString(const float* a, uint32_t m, uint32_t n, bool rowMajor) {
+ String8 str;
+ str.append("[");
+ for (size_t i = 0; i < m; i++) {
+ if (i) {
+ str.append(",");
+ }
+ str.append(" [");
+ for (size_t j = 0; j < n; j++) {
+ if (j) {
+ str.append(",");
+ }
+ str.appendFormat(" %f", a[rowMajor ? i * n + j : j * m + i]);
+ }
+ str.append(" ]");
+ }
+ str.append(" ]");
+ return str;
+}
+#endif
+
+VelocityTracker::VelocityTracker() {
+ clear();
+}
+
+void VelocityTracker::clear() {
+ mIndex = 0;
+ mMovements[0].idBits.clear();
+ mActivePointerId = -1;
+}
+
+void VelocityTracker::clearPointers(BitSet32 idBits) {
+ BitSet32 remainingIdBits(mMovements[mIndex].idBits.value & ~idBits.value);
+ mMovements[mIndex].idBits = remainingIdBits;
+
+ if (mActivePointerId >= 0 && idBits.hasBit(mActivePointerId)) {
+ mActivePointerId = !remainingIdBits.isEmpty() ? remainingIdBits.firstMarkedBit() : -1;
+ }
+}
+
+void VelocityTracker::addMovement(nsecs_t eventTime, BitSet32 idBits, const Position* positions) {
+ if (++mIndex == HISTORY_SIZE) {
+ mIndex = 0;
+ }
+
+ while (idBits.count() > MAX_POINTERS) {
+ idBits.clearLastMarkedBit();
+ }
+
+ Movement& movement = mMovements[mIndex];
+ movement.eventTime = eventTime;
+ movement.idBits = idBits;
+ uint32_t count = idBits.count();
+ for (uint32_t i = 0; i < count; i++) {
+ movement.positions[i] = positions[i];
+ }
+
+ if (mActivePointerId < 0 || !idBits.hasBit(mActivePointerId)) {
+ mActivePointerId = count != 0 ? idBits.firstMarkedBit() : -1;
+ }
+
+#if DEBUG_VELOCITY
+ ALOGD("VelocityTracker: addMovement eventTime=%lld, idBits=0x%08x, activePointerId=%d",
+ eventTime, idBits.value, mActivePointerId);
+ for (BitSet32 iterBits(idBits); !iterBits.isEmpty(); ) {
+ uint32_t id = iterBits.firstMarkedBit();
+ uint32_t index = idBits.getIndexOfBit(id);
+ iterBits.clearBit(id);
+ Estimator estimator;
+ getEstimator(id, DEFAULT_DEGREE, DEFAULT_HORIZON, &estimator);
+ ALOGD(" %d: position (%0.3f, %0.3f), "
+ "estimator (degree=%d, xCoeff=%s, yCoeff=%s, confidence=%f)",
+ id, positions[index].x, positions[index].y,
+ int(estimator.degree),
+ vectorToString(estimator.xCoeff, estimator.degree).string(),
+ vectorToString(estimator.yCoeff, estimator.degree).string(),
+ estimator.confidence);
+ }
+#endif
+}
+
+void VelocityTracker::addMovement(const MotionEvent* event) {
+ int32_t actionMasked = event->getActionMasked();
+
+ switch (actionMasked) {
+ case AMOTION_EVENT_ACTION_DOWN:
+ case AMOTION_EVENT_ACTION_HOVER_ENTER:
+ // Clear all pointers on down before adding the new movement.
+ clear();
+ break;
+ case AMOTION_EVENT_ACTION_POINTER_DOWN: {
+ // Start a new movement trace for a pointer that just went down.
+ // We do this on down instead of on up because the client may want to query the
+ // final velocity for a pointer that just went up.
+ BitSet32 downIdBits;
+ downIdBits.markBit(event->getPointerId(event->getActionIndex()));
+ clearPointers(downIdBits);
+ break;
+ }
+ case AMOTION_EVENT_ACTION_MOVE:
+ case AMOTION_EVENT_ACTION_HOVER_MOVE:
+ break;
+ default:
+ // Ignore all other actions because they do not convey any new information about
+ // pointer movement. We also want to preserve the last known velocity of the pointers.
+ // Note that ACTION_UP and ACTION_POINTER_UP always report the last known position
+ // of the pointers that went up. ACTION_POINTER_UP does include the new position of
+ // pointers that remained down but we will also receive an ACTION_MOVE with this
+ // information if any of them actually moved. Since we don't know how many pointers
+ // will be going up at once it makes sense to just wait for the following ACTION_MOVE
+ // before adding the movement.
+ return;
+ }
+
+ size_t pointerCount = event->getPointerCount();
+ if (pointerCount > MAX_POINTERS) {
+ pointerCount = MAX_POINTERS;
+ }
+
+ BitSet32 idBits;
+ for (size_t i = 0; i < pointerCount; i++) {
+ idBits.markBit(event->getPointerId(i));
+ }
+
+ nsecs_t eventTime;
+ Position positions[pointerCount];
+
+ size_t historySize = event->getHistorySize();
+ for (size_t h = 0; h < historySize; h++) {
+ eventTime = event->getHistoricalEventTime(h);
+ for (size_t i = 0; i < pointerCount; i++) {
+ positions[i].x = event->getHistoricalX(i, h);
+ positions[i].y = event->getHistoricalY(i, h);
+ }
+ addMovement(eventTime, idBits, positions);
+ }
+
+ eventTime = event->getEventTime();
+ for (size_t i = 0; i < pointerCount; i++) {
+ positions[i].x = event->getX(i);
+ positions[i].y = event->getY(i);
+ }
+ addMovement(eventTime, idBits, positions);
+}
+
+/**
+ * Solves a linear least squares problem to obtain a N degree polynomial that fits
+ * the specified input data as nearly as possible.
+ *
+ * Returns true if a solution is found, false otherwise.
+ *
+ * The input consists of two vectors of data points X and Y with indices 0..m-1.
+ * The output is a vector B with indices 0..n-1 that describes a polynomial
+ * that fits the data, such the sum of abs(Y[i] - (B[0] + B[1] X[i] + B[2] X[i]^2 ... B[n] X[i]^n))
+ * for all i between 0 and m-1 is minimized.
+ *
+ * That is to say, the function that generated the input data can be approximated
+ * by y(x) ~= B[0] + B[1] x + B[2] x^2 + ... + B[n] x^n.
+ *
+ * The coefficient of determination (R^2) is also returned to describe the goodness
+ * of fit of the model for the given data. It is a value between 0 and 1, where 1
+ * indicates perfect correspondence.
+ *
+ * This function first expands the X vector to a m by n matrix A such that
+ * A[i][0] = 1, A[i][1] = X[i], A[i][2] = X[i]^2, ..., A[i][n] = X[i]^n.
+ *
+ * Then it calculates the QR decomposition of A yielding an m by m orthonormal matrix Q
+ * and an m by n upper triangular matrix R. Because R is upper triangular (lower
+ * part is all zeroes), we can simplify the decomposition into an m by n matrix
+ * Q1 and a n by n matrix R1 such that A = Q1 R1.
+ *
+ * Finally we solve the system of linear equations given by R1 B = (Qtranspose Y)
+ * to find B.
+ *
+ * For efficiency, we lay out A and Q column-wise in memory because we frequently
+ * operate on the column vectors. Conversely, we lay out R row-wise.
+ *
+ * http://en.wikipedia.org/wiki/Numerical_methods_for_linear_least_squares
+ * http://en.wikipedia.org/wiki/Gram-Schmidt
+ */
+static bool solveLeastSquares(const float* x, const float* y, uint32_t m, uint32_t n,
+ float* outB, float* outDet) {
+#if DEBUG_LEAST_SQUARES
+ ALOGD("solveLeastSquares: m=%d, n=%d, x=%s, y=%s", int(m), int(n),
+ vectorToString(x, m).string(), vectorToString(y, m).string());
+#endif
+
+ // Expand the X vector to a matrix A.
+ float a[n][m]; // column-major order
+ for (uint32_t h = 0; h < m; h++) {
+ a[0][h] = 1;
+ for (uint32_t i = 1; i < n; i++) {
+ a[i][h] = a[i - 1][h] * x[h];
+ }
+ }
+#if DEBUG_LEAST_SQUARES
+ ALOGD(" - a=%s", matrixToString(&a[0][0], m, n, false /*rowMajor*/).string());
+#endif
+
+ // Apply the Gram-Schmidt process to A to obtain its QR decomposition.
+ float q[n][m]; // orthonormal basis, column-major order
+ float r[n][n]; // upper triangular matrix, row-major order
+ for (uint32_t j = 0; j < n; j++) {
+ for (uint32_t h = 0; h < m; h++) {
+ q[j][h] = a[j][h];
+ }
+ for (uint32_t i = 0; i < j; i++) {
+ float dot = vectorDot(&q[j][0], &q[i][0], m);
+ for (uint32_t h = 0; h < m; h++) {
+ q[j][h] -= dot * q[i][h];
+ }
+ }
+
+ float norm = vectorNorm(&q[j][0], m);
+ if (norm < 0.000001f) {
+ // vectors are linearly dependent or zero so no solution
+#if DEBUG_LEAST_SQUARES
+ ALOGD(" - no solution, norm=%f", norm);
+#endif
+ return false;
+ }
+
+ float invNorm = 1.0f / norm;
+ for (uint32_t h = 0; h < m; h++) {
+ q[j][h] *= invNorm;
+ }
+ for (uint32_t i = 0; i < n; i++) {
+ r[j][i] = i < j ? 0 : vectorDot(&q[j][0], &a[i][0], m);
+ }
+ }
+#if DEBUG_LEAST_SQUARES
+ ALOGD(" - q=%s", matrixToString(&q[0][0], m, n, false /*rowMajor*/).string());
+ ALOGD(" - r=%s", matrixToString(&r[0][0], n, n, true /*rowMajor*/).string());
+
+ // calculate QR, if we factored A correctly then QR should equal A
+ float qr[n][m];
+ for (uint32_t h = 0; h < m; h++) {
+ for (uint32_t i = 0; i < n; i++) {
+ qr[i][h] = 0;
+ for (uint32_t j = 0; j < n; j++) {
+ qr[i][h] += q[j][h] * r[j][i];
+ }
+ }
+ }
+ ALOGD(" - qr=%s", matrixToString(&qr[0][0], m, n, false /*rowMajor*/).string());
+#endif
+
+ // Solve R B = Qt Y to find B. This is easy because R is upper triangular.
+ // We just work from bottom-right to top-left calculating B's coefficients.
+ for (uint32_t i = n; i-- != 0; ) {
+ outB[i] = vectorDot(&q[i][0], y, m);
+ for (uint32_t j = n - 1; j > i; j--) {
+ outB[i] -= r[i][j] * outB[j];
+ }
+ outB[i] /= r[i][i];
+ }
+#if DEBUG_LEAST_SQUARES
+ ALOGD(" - b=%s", vectorToString(outB, n).string());
+#endif
+
+ // Calculate the coefficient of determination as 1 - (SSerr / SStot) where
+ // SSerr is the residual sum of squares (squared variance of the error),
+ // and SStot is the total sum of squares (squared variance of the data).
+ float ymean = 0;
+ for (uint32_t h = 0; h < m; h++) {
+ ymean += y[h];
+ }
+ ymean /= m;
+
+ float sserr = 0;
+ float sstot = 0;
+ for (uint32_t h = 0; h < m; h++) {
+ float err = y[h] - outB[0];
+ float term = 1;
+ for (uint32_t i = 1; i < n; i++) {
+ term *= x[h];
+ err -= term * outB[i];
+ }
+ sserr += err * err;
+ float var = y[h] - ymean;
+ sstot += var * var;
+ }
+ *outDet = sstot > 0.000001f ? 1.0f - (sserr / sstot) : 1;
+#if DEBUG_LEAST_SQUARES
+ ALOGD(" - sserr=%f", sserr);
+ ALOGD(" - sstot=%f", sstot);
+ ALOGD(" - det=%f", *outDet);
+#endif
+ return true;
+}
+
+bool VelocityTracker::getVelocity(uint32_t id, float* outVx, float* outVy) const {
+ Estimator estimator;
+ if (getEstimator(id, DEFAULT_DEGREE, DEFAULT_HORIZON, &estimator)) {
+ if (estimator.degree >= 1) {
+ *outVx = estimator.xCoeff[1];
+ *outVy = estimator.yCoeff[1];
+ return true;
+ }
+ }
+ *outVx = 0;
+ *outVy = 0;
+ return false;
+}
+
+bool VelocityTracker::getEstimator(uint32_t id, uint32_t degree, nsecs_t horizon,
+ Estimator* outEstimator) const {
+ outEstimator->clear();
+
+ // Iterate over movement samples in reverse time order and collect samples.
+ float x[HISTORY_SIZE];
+ float y[HISTORY_SIZE];
+ float time[HISTORY_SIZE];
+ uint32_t m = 0;
+ uint32_t index = mIndex;
+ const Movement& newestMovement = mMovements[mIndex];
+ do {
+ const Movement& movement = mMovements[index];
+ if (!movement.idBits.hasBit(id)) {
+ break;
+ }
+
+ nsecs_t age = newestMovement.eventTime - movement.eventTime;
+ if (age > horizon) {
+ break;
+ }
+
+ const Position& position = movement.getPosition(id);
+ x[m] = position.x;
+ y[m] = position.y;
+ time[m] = -age * 0.000000001f;
+ index = (index == 0 ? HISTORY_SIZE : index) - 1;
+ } while (++m < HISTORY_SIZE);
+
+ if (m == 0) {
+ return false; // no data
+ }
+
+ // Calculate a least squares polynomial fit.
+ if (degree > Estimator::MAX_DEGREE) {
+ degree = Estimator::MAX_DEGREE;
+ }
+ if (degree > m - 1) {
+ degree = m - 1;
+ }
+ if (degree >= 1) {
+ float xdet, ydet;
+ uint32_t n = degree + 1;
+ if (solveLeastSquares(time, x, m, n, outEstimator->xCoeff, &xdet)
+ && solveLeastSquares(time, y, m, n, outEstimator->yCoeff, &ydet)) {
+ outEstimator->degree = degree;
+ outEstimator->confidence = xdet * ydet;
+#if DEBUG_LEAST_SQUARES
+ ALOGD("estimate: degree=%d, xCoeff=%s, yCoeff=%s, confidence=%f",
+ int(outEstimator->degree),
+ vectorToString(outEstimator->xCoeff, n).string(),
+ vectorToString(outEstimator->yCoeff, n).string(),
+ outEstimator->confidence);
+#endif
+ return true;
+ }
+ }
+
+ // No velocity data available for this pointer, but we do have its current position.
+ outEstimator->xCoeff[0] = x[0];
+ outEstimator->yCoeff[0] = y[0];
+ outEstimator->degree = 0;
+ outEstimator->confidence = 1;
+ return true;
+}
+
+} // namespace android
diff --git a/services/input/InputReader.h b/services/input/InputReader.h
index 03198a6..122a2ab 100644
--- a/services/input/InputReader.h
+++ b/services/input/InputReader.h
@@ -22,6 +22,8 @@
#include "InputListener.h"
#include <androidfw/Input.h>
+#include <androidfw/VelocityControl.h>
+#include <androidfw/VelocityTracker.h>
#include <ui/DisplayInfo.h>
#include <utils/KeyedVector.h>
#include <utils/threads.h>
diff --git a/services/input/PointerController.h b/services/input/PointerController.h
index 39dbf6b..4c307c4 100644
--- a/services/input/PointerController.h
+++ b/services/input/PointerController.h
@@ -21,6 +21,7 @@
#include <ui/DisplayInfo.h>
#include <androidfw/Input.h>
+#include <utils/BitSet.h>
#include <utils/RefBase.h>
#include <utils/Looper.h>
#include <utils/String8.h>
