Refactor SwipeTracker class
This change moves SwipeTracker out from LatinKeyboardBaseView. Also
this introduces EventBuffer class for swipe tracking buffer.
Bug: 2910379
Change-Id: I48ff714226a248ca063cbaf9755cf45e458f7402
diff --git a/java/src/com/android/inputmethod/latin/LatinKeyboardBaseView.java b/java/src/com/android/inputmethod/latin/LatinKeyboardBaseView.java
index 7247632..346daa3 100644
--- a/java/src/com/android/inputmethod/latin/LatinKeyboardBaseView.java
+++ b/java/src/com/android/inputmethod/latin/LatinKeyboardBaseView.java
@@ -1286,7 +1286,6 @@
}
// 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.
diff --git a/java/src/com/android/inputmethod/latin/SwipeTracker.java b/java/src/com/android/inputmethod/latin/SwipeTracker.java
index 007c8e7..31f7cb3 100644
--- a/java/src/com/android/inputmethod/latin/SwipeTracker.java
+++ b/java/src/com/android/inputmethod/latin/SwipeTracker.java
@@ -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;
- }
+ buffer.dropOldest();
}
- 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.add(x, y, time);
}
public void computeCurrentVelocity(int units) {
@@ -87,33 +57,24 @@
}
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 @@
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);
+ }
+ }
}
\ No newline at end of file
diff --git a/tests/src/com/android/inputmethod/latin/EventRingBufferTests.java b/tests/src/com/android/inputmethod/latin/EventRingBufferTests.java
new file mode 100644
index 0000000..620f036
--- /dev/null
+++ b/tests/src/com/android/inputmethod/latin/EventRingBufferTests.java
@@ -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
+ }
+}