Refactor SwipeTracker class (dfbc5080) · Commits · e / os / android_packages_inputmethods_LatinIME

java/src/com/android/inputmethod/latin/LatinKeyboardBaseView.java

+0 −1

Original line number	Diff line number	Diff line
		@@ -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.

java/src/com/android/inputmethod/latin/SwipeTracker.java

+91 −66

Original line number	Diff line number	Diff line
		@@ -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) {
		@@ -87,32 +57,23 @@ 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 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;
		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);
		}
		}
		}
		No newline at end of file

tests/src/com/android/inputmethod/latin/EventRingBufferTests.java

0 → 100644

+154 −0

Original line number	Diff line number	Diff line
		/*
		* 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
		}
		}