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am dfbc5080: Refactor SwipeTracker class

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Merge commit 'dfbc5080a1b639fda448098ab080d632639591dc' into gingerbread-plus-aosp

* commit 'dfbc5080a1b639fda448098ab080d632639591dc':
  Refactor SwipeTracker class
This commit is contained in:
Tadashi G. Takaoka 2010-08-26 07:31:24 -07:00 committed by Android Git Automerger
commit 6056fee826
3 changed files with 245 additions and 67 deletions
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1
java/src/com/android/inputmethod/latin/LatinKeyboardBaseView.java
View file

@ -1286,7 +1286,6 @@ public class LatinKeyboardBaseView extends View implements View.OnClickListener
}
// Track the last few movements to look for spurious swipes.
if (action == MotionEvent.ACTION_DOWN) mSwipeTracker.clear();
mSwipeTracker.addMovement(me);
// Ignore all motion events until a DOWN.

157
java/src/com/android/inputmethod/latin/SwipeTracker.java
View file

@ -16,70 +16,40 @@
package com.android.inputmethod.latin;
import android.util.Log;
import android.view.MotionEvent;
class SwipeTracker {
private static final int NUM_PAST = 4;
private static final int LONGEST_PAST_TIME = 200;
static final int NUM_PAST = 4;
static final int LONGEST_PAST_TIME = 200;
final EventRingBuffer mBuffer = new EventRingBuffer(NUM_PAST);
final float mPastX[] = new float[NUM_PAST];
final float mPastY[] = new float[NUM_PAST];
final long mPastTime[] = new long[NUM_PAST];
float mYVelocity;
float mXVelocity;
public void clear() {
mPastTime[0] = 0;
}
private float mYVelocity;
private float mXVelocity;
public void addMovement(MotionEvent ev) {
if (ev.getAction() == MotionEvent.ACTION_DOWN) {
clear();
mBuffer.clear();
return;
}
long time = ev.getEventTime();
final int N = ev.getHistorySize();
for (int i=0; i<N; i++) {
addPoint(ev.getHistoricalX(i), ev.getHistoricalY(i),
ev.getHistoricalEventTime(i));
final int count = ev.getHistorySize();
for (int i = 0; i < count; i++) {
addPoint(ev.getHistoricalX(i), ev.getHistoricalY(i), ev.getHistoricalEventTime(i));
}
addPoint(ev.getX(), ev.getY(), time);
}
private void addPoint(float x, float y, long time) {
int drop = -1;
int i;
final long[] pastTime = mPastTime;
for (i=0; i<NUM_PAST; i++) {
if (pastTime[i] == 0) {
final EventRingBuffer buffer = mBuffer;
while (buffer.size() > 0) {
long lastT = buffer.getTime(0);
if (lastT >= time - LONGEST_PAST_TIME)
break;
} else if (pastTime[i] < time-LONGEST_PAST_TIME) {
drop = i;
}
}
if (i == NUM_PAST && drop < 0) {
drop = 0;
}
if (drop == i) drop--;
final float[] pastX = mPastX;
final float[] pastY = mPastY;
if (drop >= 0) {
final int start = drop+1;
final int count = NUM_PAST-drop-1;
System.arraycopy(pastX, start, pastX, 0, count);
System.arraycopy(pastY, start, pastY, 0, count);
System.arraycopy(pastTime, start, pastTime, 0, count);
i -= (drop+1);
}
pastX[i] = x;
pastY[i] = y;
pastTime[i] = time;
i++;
if (i < NUM_PAST) {
pastTime[i] = 0;
buffer.dropOldest();
}
buffer.add(x, y, time);
}
public void computeCurrentVelocity(int units) {
@ -87,33 +57,24 @@ class SwipeTracker {
}
public void computeCurrentVelocity(int units, float maxVelocity) {
final float[] pastX = mPastX;
final float[] pastY = mPastY;
final long[] pastTime = mPastTime;
final EventRingBuffer buffer = mBuffer;
final float oldestX = buffer.getX(0);
final float oldestY = buffer.getY(0);
final long oldestTime = buffer.getTime(0);
final float oldestX = pastX[0];
final float oldestY = pastY[0];
final long oldestTime = pastTime[0];
float accumX = 0;
float accumY = 0;
int N=0;
while (N < NUM_PAST) {
if (pastTime[N] == 0) {
break;
}
N++;
}
for (int i=1; i < N; i++) {
final int dur = (int)(pastTime[i] - oldestTime);
final int count = buffer.size();
for (int pos = 1; pos < count; pos++) {
final int dur = (int)(buffer.getTime(pos) - oldestTime);
if (dur == 0) continue;
float dist = pastX[i] - oldestX;
float vel = (dist/dur) * units; // pixels/frame.
float dist = buffer.getX(pos) - oldestX;
float vel = (dist / dur) * units; // pixels/frame.
if (accumX == 0) accumX = vel;
else accumX = (accumX + vel) * .5f;
dist = pastY[i] - oldestY;
vel = (dist/dur) * units; // pixels/frame.
dist = buffer.getY(pos) - oldestY;
vel = (dist / dur) * units; // pixels/frame.
if (accumY == 0) accumY = vel;
else accumY = (accumY + vel) * .5f;
}
@ -130,4 +91,68 @@ class SwipeTracker {
public float getYVelocity() {
return mYVelocity;
}
static class EventRingBuffer {
private final int bufSize;
private final float xBuf[];
private final float yBuf[];
private final long timeBuf[];
private int top; // points new event
private int end; // points oldest event
private int count; // the number of valid data
public EventRingBuffer(int max) {
this.bufSize = max;
xBuf = new float[max];
yBuf = new float[max];
timeBuf = new long[max];
clear();
}
public void clear() {
top = end = count = 0;
}
public int size() {
return count;
}
// Position 0 points oldest event
private int index(int pos) {
return (end + pos) % bufSize;
}
private int advance(int index) {
return (index + 1) % bufSize;
}
public void add(float x, float y, long time) {
xBuf[top] = x;
yBuf[top] = y;
timeBuf[top] = time;
top = advance(top);
if (count < bufSize) {
count++;
} else {
end = advance(end);
}
}
public float getX(int pos) {
return xBuf[index(pos)];
}
public float getY(int pos) {
return yBuf[index(pos)];
}
public long getTime(int pos) {
return timeBuf[index(pos)];
}
public void dropOldest() {
count--;
end = advance(end);
}
}
}

154
tests/src/com/android/inputmethod/latin/EventRingBufferTests.java Normal file
View file

@ -0,0 +1,154 @@
/*
* Copyright (C) 2010 Google Inc.
*
* 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.
*/
package com.android.inputmethod.latin;
import com.android.inputmethod.latin.SwipeTracker.EventRingBuffer;
import android.test.AndroidTestCase;
public class EventRingBufferTests extends AndroidTestCase {
@Override
protected void setUp() throws Exception {
super.setUp();
}
@Override
protected void tearDown() throws Exception {
super.tearDown();
}
private static float X_BASE = 1000f;
private static float Y_BASE = 2000f;
private static long TIME_BASE = 3000l;
private static float x(int id) {
return X_BASE + id;
}
private static float y(int id) {
return Y_BASE + id;
}
private static long time(int id) {
return TIME_BASE + id;
}
private static void addEvent(EventRingBuffer buf, int id) {
buf.add(x(id), y(id), time(id));
}
private static void assertEventSize(EventRingBuffer buf, int size) {
assertEquals(size, buf.size());
}
private static void assertEvent(EventRingBuffer buf, int pos, int id) {
assertEquals(x(id), buf.getX(pos), 0f);
assertEquals(y(id), buf.getY(pos), 0f);
assertEquals(time(id), buf.getTime(pos));
}
public void testClearBuffer() {
EventRingBuffer buf = new EventRingBuffer(4);
assertEventSize(buf, 0);
addEvent(buf, 0);
addEvent(buf, 1);
addEvent(buf, 2);
addEvent(buf, 3);
addEvent(buf, 4);
assertEventSize(buf, 4);
buf.clear();
assertEventSize(buf, 0);
}
public void testRingBuffer() {
EventRingBuffer buf = new EventRingBuffer(4);
assertEventSize(buf, 0); // [0]
addEvent(buf, 0);
assertEventSize(buf, 1); // [1] 0
assertEvent(buf, 0, 0);
addEvent(buf, 1);
addEvent(buf, 2);
assertEventSize(buf, 3); // [3] 2 1 0
assertEvent(buf, 0, 0);
assertEvent(buf, 1, 1);
assertEvent(buf, 2, 2);
addEvent(buf, 3);
assertEventSize(buf, 4); // [4] 3 2 1 0
assertEvent(buf, 0, 0);
assertEvent(buf, 1, 1);
assertEvent(buf, 2, 2);
assertEvent(buf, 3, 3);
addEvent(buf, 4);
addEvent(buf, 5);
assertEventSize(buf, 4); // [4] 5 4|3 2(1 0)
assertEvent(buf, 0, 2);
assertEvent(buf, 1, 3);
assertEvent(buf, 2, 4);
assertEvent(buf, 3, 5);
addEvent(buf, 6);
addEvent(buf, 7);
addEvent(buf, 8);
assertEventSize(buf, 4); // [4] 8 7 6 5|(4 3 2)1|0
assertEvent(buf, 0, 5);
assertEvent(buf, 1, 6);
assertEvent(buf, 2, 7);
assertEvent(buf, 3, 8);
}
public void testDropOldest() {
EventRingBuffer buf = new EventRingBuffer(4);
addEvent(buf, 0);
assertEventSize(buf, 1); // [1] 0
assertEvent(buf, 0, 0);
buf.dropOldest();
assertEventSize(buf, 0); // [0] (0)
addEvent(buf, 1);
addEvent(buf, 2);
addEvent(buf, 3);
addEvent(buf, 4);
assertEventSize(buf, 4); // [4] 4|3 2 1(0)
assertEvent(buf, 0, 1);
buf.dropOldest();
assertEventSize(buf, 3); // [3] 4|3 2(1)0
assertEvent(buf, 0, 2);
buf.dropOldest();
assertEventSize(buf, 2); // [2] 4|3(2)10
assertEvent(buf, 0, 3);
buf.dropOldest();
assertEventSize(buf, 1); // [1] 4|(3)210
assertEvent(buf, 0, 4);
buf.dropOldest();
assertEventSize(buf, 0); // [0] (4)|3210
}
}