ScaleGestureDetector.java revision 5b5c414e31c4a8433a3290b931687a05dadc97b6
1ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell/* 2ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * Copyright (C) 2010 The Android Open Source Project 3ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * 4ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * Licensed under the Apache License, Version 2.0 (the "License"); 5ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * you may not use this file except in compliance with the License. 6ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * You may obtain a copy of the License at 7ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * 8ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * http://www.apache.org/licenses/LICENSE-2.0 9ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * 10ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * Unless required by applicable law or agreed to in writing, software 11ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * distributed under the License is distributed on an "AS IS" BASIS, 12ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * See the License for the specific language governing permissions and 14ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * limitations under the License. 15ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell */ 16ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 17ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powellpackage android.view; 18ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 19ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powellimport android.content.Context; 20a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powellimport android.os.SystemClock; 21346c8fb036b99a33756c66dcebeb5d0f67a1df72Adam Powellimport android.util.FloatMath; 22a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell 23ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell/** 24618cbea4e746196cbde43746706bec02e14b487bAdam Powell * Detects scaling transformation gestures using the supplied {@link MotionEvent}s. 25618cbea4e746196cbde43746706bec02e14b487bAdam Powell * The {@link OnScaleGestureListener} callback will notify users when a particular 26618cbea4e746196cbde43746706bec02e14b487bAdam Powell * gesture event has occurred. 27618cbea4e746196cbde43746706bec02e14b487bAdam Powell * 28ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * This class should only be used with {@link MotionEvent}s reported via touch. 2947c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 30ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * To use this class: 31ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * <ul> 32ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * <li>Create an instance of the {@code ScaleGestureDetector} for your 33ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * {@link View} 34ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * <li>In the {@link View#onTouchEvent(MotionEvent)} method ensure you call 35ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * {@link #onTouchEvent(MotionEvent)}. The methods defined in your 36ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * callback will be executed when the events occur. 37ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * </ul> 38ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell */ 39ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powellpublic class ScaleGestureDetector { 400818020d7cb04d83d51b71b8262d34bd79a76a95Adam Powell private static final String TAG = "ScaleGestureDetector"; 410818020d7cb04d83d51b71b8262d34bd79a76a95Adam Powell 42ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell /** 43ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * The listener for receiving notifications when gestures occur. 44ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * If you want to listen for all the different gestures then implement 45ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * this interface. If you only want to listen for a subset it might 46ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * be easier to extend {@link SimpleOnScaleGestureListener}. 4747c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 48ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * An application will receive events in the following order: 49ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * <ul> 50ab905c87b7324d15715b78eaae7ef8558ad3bd10Adam Powell * <li>One {@link OnScaleGestureListener#onScaleBegin(ScaleGestureDetector)} 51ab905c87b7324d15715b78eaae7ef8558ad3bd10Adam Powell * <li>Zero or more {@link OnScaleGestureListener#onScale(ScaleGestureDetector)} 52ab905c87b7324d15715b78eaae7ef8558ad3bd10Adam Powell * <li>One {@link OnScaleGestureListener#onScaleEnd(ScaleGestureDetector)} 53ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * </ul> 54ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell */ 55ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public interface OnScaleGestureListener { 56ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell /** 57ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * Responds to scaling events for a gesture in progress. 58ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * Reported by pointer motion. 5947c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 60ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * @param detector The detector reporting the event - use this to 61ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * retrieve extended info about event state. 62ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * @return Whether or not the detector should consider this event 63ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * as handled. If an event was not handled, the detector 64ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * will continue to accumulate movement until an event is 65ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * handled. This can be useful if an application, for example, 66ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * only wants to update scaling factors if the change is 67ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * greater than 0.01. 68ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell */ 69ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public boolean onScale(ScaleGestureDetector detector); 70ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 71ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell /** 72ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * Responds to the beginning of a scaling gesture. Reported by 73ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * new pointers going down. 7447c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 75ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * @param detector The detector reporting the event - use this to 76ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * retrieve extended info about event state. 77ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * @return Whether or not the detector should continue recognizing 78ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * this gesture. For example, if a gesture is beginning 79ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * with a focal point outside of a region where it makes 80ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * sense, onScaleBegin() may return false to ignore the 81ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * rest of the gesture. 82ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell */ 83ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public boolean onScaleBegin(ScaleGestureDetector detector); 84ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 85ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell /** 86ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * Responds to the end of a scale gesture. Reported by existing 87216bccf804db9c972b317620a27de6a8adf7fbfeAdam Powell * pointers going up. 8847c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 89ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * Once a scale has ended, {@link ScaleGestureDetector#getFocusX()} 9047ec2fb37046797bebc82b505a13c552021b9ff3Adam Powell * and {@link ScaleGestureDetector#getFocusY()} will return focal point 9147ec2fb37046797bebc82b505a13c552021b9ff3Adam Powell * of the pointers remaining on the screen. 9247c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 93ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * @param detector The detector reporting the event - use this to 94ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * retrieve extended info about event state. 95ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell */ 96ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public void onScaleEnd(ScaleGestureDetector detector); 97ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 9847c41e807e36999e4d0d2072e41a82bc45655ff2Erik 99ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell /** 100ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * A convenience class to extend when you only want to listen for a subset 101ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * of scaling-related events. This implements all methods in 102ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * {@link OnScaleGestureListener} but does nothing. 103346c8fb036b99a33756c66dcebeb5d0f67a1df72Adam Powell * {@link OnScaleGestureListener#onScale(ScaleGestureDetector)} returns 104346c8fb036b99a33756c66dcebeb5d0f67a1df72Adam Powell * {@code false} so that a subclass can retrieve the accumulated scale 105346c8fb036b99a33756c66dcebeb5d0f67a1df72Adam Powell * factor in an overridden onScaleEnd. 106346c8fb036b99a33756c66dcebeb5d0f67a1df72Adam Powell * {@link OnScaleGestureListener#onScaleBegin(ScaleGestureDetector)} returns 10747c41e807e36999e4d0d2072e41a82bc45655ff2Erik * {@code true}. 108ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell */ 109216bccf804db9c972b317620a27de6a8adf7fbfeAdam Powell public static class SimpleOnScaleGestureListener implements OnScaleGestureListener { 110ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 111ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public boolean onScale(ScaleGestureDetector detector) { 112346c8fb036b99a33756c66dcebeb5d0f67a1df72Adam Powell return false; 113ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 114ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 115ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public boolean onScaleBegin(ScaleGestureDetector detector) { 116ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell return true; 117ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 118ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 119ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public void onScaleEnd(ScaleGestureDetector detector) { 120ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell // Intentionally empty 121ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 122ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 123ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 124346c8fb036b99a33756c66dcebeb5d0f67a1df72Adam Powell private final Context mContext; 125346c8fb036b99a33756c66dcebeb5d0f67a1df72Adam Powell private final OnScaleGestureListener mListener; 126ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 127ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell private float mFocusX; 128ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell private float mFocusY; 129618cbea4e746196cbde43746706bec02e14b487bAdam Powell 130618cbea4e746196cbde43746706bec02e14b487bAdam Powell private float mCurrSpan; 131618cbea4e746196cbde43746706bec02e14b487bAdam Powell private float mPrevSpan; 13247ec2fb37046797bebc82b505a13c552021b9ff3Adam Powell private float mInitialSpan; 133618cbea4e746196cbde43746706bec02e14b487bAdam Powell private float mCurrSpanX; 134618cbea4e746196cbde43746706bec02e14b487bAdam Powell private float mCurrSpanY; 135618cbea4e746196cbde43746706bec02e14b487bAdam Powell private float mPrevSpanX; 136618cbea4e746196cbde43746706bec02e14b487bAdam Powell private float mPrevSpanY; 137618cbea4e746196cbde43746706bec02e14b487bAdam Powell private long mCurrTime; 138618cbea4e746196cbde43746706bec02e14b487bAdam Powell private long mPrevTime; 139618cbea4e746196cbde43746706bec02e14b487bAdam Powell private boolean mInProgress; 14047ec2fb37046797bebc82b505a13c552021b9ff3Adam Powell private int mSpanSlop; 141828e56ea6e8f4d5aa650052580f1f7873ad8296dAdam Powell private int mMinSpan; 142e33cef8037cb87386e17bcf8701a47452d262fa6Adam Powell 1435b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell // Bounds for recently seen values 1445b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell private float mTouchUpper; 1455b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell private float mTouchLower; 1465b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell private float mTouchHistoryLastAccepted; 1475b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell private int mTouchHistoryDirection; 1485b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell private long mTouchHistoryLastAcceptedTime; 1495b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell private int mTouchMinMajor; 150a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell 151d736d2069b94348b519089348f4a85eb482db668Adam Powell private static final long TOUCH_STABILIZE_TIME = 128; // ms 1525b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell private static final int TOUCH_MIN_MAJOR = 48; // dp 153a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell 15421bc5c917d4ee2a9b2b8173091e6bba85eaff899Jeff Brown /** 15521bc5c917d4ee2a9b2b8173091e6bba85eaff899Jeff Brown * Consistency verifier for debugging purposes. 15621bc5c917d4ee2a9b2b8173091e6bba85eaff899Jeff Brown */ 15721bc5c917d4ee2a9b2b8173091e6bba85eaff899Jeff Brown private final InputEventConsistencyVerifier mInputEventConsistencyVerifier = 15821bc5c917d4ee2a9b2b8173091e6bba85eaff899Jeff Brown InputEventConsistencyVerifier.isInstrumentationEnabled() ? 15921bc5c917d4ee2a9b2b8173091e6bba85eaff899Jeff Brown new InputEventConsistencyVerifier(this, 0) : null; 16021bc5c917d4ee2a9b2b8173091e6bba85eaff899Jeff Brown 161ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public ScaleGestureDetector(Context context, OnScaleGestureListener listener) { 162ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell mContext = context; 163ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell mListener = listener; 16447ec2fb37046797bebc82b505a13c552021b9ff3Adam Powell mSpanSlop = ViewConfiguration.get(context).getScaledTouchSlop() * 2; 1655b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell mTouchMinMajor = 1665b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell (int) (context.getResources().getDisplayMetrics().density * TOUCH_MIN_MAJOR + 0.5f); 167828e56ea6e8f4d5aa650052580f1f7873ad8296dAdam Powell mMinSpan = context.getResources().getDimensionPixelSize( 168828e56ea6e8f4d5aa650052580f1f7873ad8296dAdam Powell com.android.internal.R.dimen.config_minScalingSpan); 169ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 170ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 171618cbea4e746196cbde43746706bec02e14b487bAdam Powell /** 172a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell * The touchMajor/touchMinor elements of a MotionEvent can flutter/jitter on 173a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell * some hardware/driver combos. Smooth it out to get kinder, gentler behavior. 174a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell * @param ev MotionEvent to add to the ongoing history 175a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell */ 176a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell private void addTouchHistory(MotionEvent ev) { 177a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell final long currentTime = SystemClock.uptimeMillis(); 178a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell final int count = ev.getPointerCount(); 1795b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell boolean accept = currentTime - mTouchHistoryLastAcceptedTime >= TOUCH_STABILIZE_TIME; 1805b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell float total = 0; 1815b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell int sampleCount = 0; 182a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell for (int i = 0; i < count; i++) { 1835b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell final boolean hasLastAccepted = !Float.isNaN(mTouchHistoryLastAccepted); 184a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell final int historySize = ev.getHistorySize(); 1855b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell final int pointerSampleCount = historySize + 1; 1865b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell for (int h = 0; h < pointerSampleCount; h++) { 1875b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell float major; 188a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell if (h < historySize) { 189a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell major = ev.getHistoricalTouchMajor(i, h); 190a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell } else { 191a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell major = ev.getTouchMajor(i); 192a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell } 1935b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell if (major < mTouchMinMajor) major = mTouchMinMajor; 1945b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell total += major; 1955b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell 1965b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell if (Float.isNaN(mTouchUpper) || major > mTouchUpper) { 1975b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell mTouchUpper = major; 1985b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell } 1995b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell if (Float.isNaN(mTouchLower) || major < mTouchLower) { 2005b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell mTouchLower = major; 2015b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell } 202a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell 203a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell if (hasLastAccepted) { 2045b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell final int directionSig = (int) Math.signum(major - mTouchHistoryLastAccepted); 2055b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell if (directionSig != mTouchHistoryDirection || 2065b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell (directionSig == 0 && mTouchHistoryDirection == 0)) { 2075b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell mTouchHistoryDirection = directionSig; 208a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell final long time = h < historySize ? ev.getHistoricalEventTime(h) 209a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell : ev.getEventTime(); 2105b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell mTouchHistoryLastAcceptedTime = time; 211a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell accept = false; 212a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell } 213a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell } 214a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell } 2155b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell sampleCount += pointerSampleCount; 216a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell } 217a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell 2185b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell final float avg = total / sampleCount; 219a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell 2205b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell if (accept) { 2215b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell float newAccepted = (mTouchUpper + mTouchLower + avg) / 3; 2225b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell mTouchUpper = (mTouchUpper + newAccepted) / 2; 2235b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell mTouchLower = (mTouchLower + newAccepted) / 2; 2245b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell mTouchHistoryLastAccepted = newAccepted; 2255b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell mTouchHistoryDirection = 0; 2265b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell mTouchHistoryLastAcceptedTime = ev.getEventTime(); 227f3a2bf8edd2e070a24f0d7c105d78b38576e14acAdam Powell } 228a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell } 229a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell 230a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell /** 231a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell * Clear all touch history tracking. Useful in ACTION_CANCEL or ACTION_UP. 232a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell * @see #addTouchHistory(MotionEvent) 233a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell */ 234a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell private void clearTouchHistory() { 2355b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell mTouchUpper = Float.NaN; 2365b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell mTouchLower = Float.NaN; 2375b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell mTouchHistoryLastAccepted = Float.NaN; 2385b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell mTouchHistoryDirection = 0; 2395b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell mTouchHistoryLastAcceptedTime = 0; 240a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell } 241a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell 242a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell /** 243618cbea4e746196cbde43746706bec02e14b487bAdam Powell * Accepts MotionEvents and dispatches events to a {@link OnScaleGestureListener} 244618cbea4e746196cbde43746706bec02e14b487bAdam Powell * when appropriate. 245618cbea4e746196cbde43746706bec02e14b487bAdam Powell * 246618cbea4e746196cbde43746706bec02e14b487bAdam Powell * <p>Applications should pass a complete and consistent event stream to this method. 247618cbea4e746196cbde43746706bec02e14b487bAdam Powell * A complete and consistent event stream involves all MotionEvents from the initial 248618cbea4e746196cbde43746706bec02e14b487bAdam Powell * ACTION_DOWN to the final ACTION_UP or ACTION_CANCEL.</p> 249618cbea4e746196cbde43746706bec02e14b487bAdam Powell * 250618cbea4e746196cbde43746706bec02e14b487bAdam Powell * @param event The event to process 251618cbea4e746196cbde43746706bec02e14b487bAdam Powell * @return true if the event was processed and the detector wants to receive the 252618cbea4e746196cbde43746706bec02e14b487bAdam Powell * rest of the MotionEvents in this event stream. 253618cbea4e746196cbde43746706bec02e14b487bAdam Powell */ 254ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public boolean onTouchEvent(MotionEvent event) { 25521bc5c917d4ee2a9b2b8173091e6bba85eaff899Jeff Brown if (mInputEventConsistencyVerifier != null) { 25621bc5c917d4ee2a9b2b8173091e6bba85eaff899Jeff Brown mInputEventConsistencyVerifier.onTouchEvent(event, 0); 25721bc5c917d4ee2a9b2b8173091e6bba85eaff899Jeff Brown } 25821bc5c917d4ee2a9b2b8173091e6bba85eaff899Jeff Brown 259e33cef8037cb87386e17bcf8701a47452d262fa6Adam Powell final int action = event.getActionMasked(); 260ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 261618cbea4e746196cbde43746706bec02e14b487bAdam Powell final boolean streamComplete = action == MotionEvent.ACTION_UP || 262618cbea4e746196cbde43746706bec02e14b487bAdam Powell action == MotionEvent.ACTION_CANCEL; 263618cbea4e746196cbde43746706bec02e14b487bAdam Powell if (action == MotionEvent.ACTION_DOWN || streamComplete) { 264618cbea4e746196cbde43746706bec02e14b487bAdam Powell // Reset any scale in progress with the listener. 265618cbea4e746196cbde43746706bec02e14b487bAdam Powell // If it's an ACTION_DOWN we're beginning a new event stream. 266618cbea4e746196cbde43746706bec02e14b487bAdam Powell // This means the app probably didn't give us all the events. Shame on it. 267618cbea4e746196cbde43746706bec02e14b487bAdam Powell if (mInProgress) { 268618cbea4e746196cbde43746706bec02e14b487bAdam Powell mListener.onScaleEnd(this); 269618cbea4e746196cbde43746706bec02e14b487bAdam Powell mInProgress = false; 27047ec2fb37046797bebc82b505a13c552021b9ff3Adam Powell mInitialSpan = 0; 271ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 272618cbea4e746196cbde43746706bec02e14b487bAdam Powell 273618cbea4e746196cbde43746706bec02e14b487bAdam Powell if (streamComplete) { 274a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell clearTouchHistory(); 275618cbea4e746196cbde43746706bec02e14b487bAdam Powell return true; 276ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 277ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 278bbdc50b102faf52768ac3028bc49e027ff140656Jeff Brown 279abde042a824c3fc2f3537ef136017dfa006258b9Adam Powell final boolean configChanged = action == MotionEvent.ACTION_DOWN || 280618cbea4e746196cbde43746706bec02e14b487bAdam Powell action == MotionEvent.ACTION_POINTER_UP || 281618cbea4e746196cbde43746706bec02e14b487bAdam Powell action == MotionEvent.ACTION_POINTER_DOWN; 282618cbea4e746196cbde43746706bec02e14b487bAdam Powell final boolean pointerUp = action == MotionEvent.ACTION_POINTER_UP; 283618cbea4e746196cbde43746706bec02e14b487bAdam Powell final int skipIndex = pointerUp ? event.getActionIndex() : -1; 284618cbea4e746196cbde43746706bec02e14b487bAdam Powell 285618cbea4e746196cbde43746706bec02e14b487bAdam Powell // Determine focal point 286618cbea4e746196cbde43746706bec02e14b487bAdam Powell float sumX = 0, sumY = 0; 287618cbea4e746196cbde43746706bec02e14b487bAdam Powell final int count = event.getPointerCount(); 288618cbea4e746196cbde43746706bec02e14b487bAdam Powell for (int i = 0; i < count; i++) { 289618cbea4e746196cbde43746706bec02e14b487bAdam Powell if (skipIndex == i) continue; 290618cbea4e746196cbde43746706bec02e14b487bAdam Powell sumX += event.getX(i); 291618cbea4e746196cbde43746706bec02e14b487bAdam Powell sumY += event.getY(i); 292bbdc50b102faf52768ac3028bc49e027ff140656Jeff Brown } 293618cbea4e746196cbde43746706bec02e14b487bAdam Powell final int div = pointerUp ? count - 1 : count; 294618cbea4e746196cbde43746706bec02e14b487bAdam Powell final float focusX = sumX / div; 295618cbea4e746196cbde43746706bec02e14b487bAdam Powell final float focusY = sumY / div; 296618cbea4e746196cbde43746706bec02e14b487bAdam Powell 2975b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell 2985b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell addTouchHistory(event); 299a4ce6ae0d379c8866697d064cfd1661ea156405eAdam Powell 300618cbea4e746196cbde43746706bec02e14b487bAdam Powell // Determine average deviation from focal point 301618cbea4e746196cbde43746706bec02e14b487bAdam Powell float devSumX = 0, devSumY = 0; 302618cbea4e746196cbde43746706bec02e14b487bAdam Powell for (int i = 0; i < count; i++) { 303618cbea4e746196cbde43746706bec02e14b487bAdam Powell if (skipIndex == i) continue; 304828e56ea6e8f4d5aa650052580f1f7873ad8296dAdam Powell 3055b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell // Convert the resulting diameter into a radius. 3065b5c414e31c4a8433a3290b931687a05dadc97b6Adam Powell final float touchSize = mTouchHistoryLastAccepted / 2; 307828e56ea6e8f4d5aa650052580f1f7873ad8296dAdam Powell devSumX += Math.abs(event.getX(i) - focusX) + touchSize; 308828e56ea6e8f4d5aa650052580f1f7873ad8296dAdam Powell devSumY += Math.abs(event.getY(i) - focusY) + touchSize; 309e33cef8037cb87386e17bcf8701a47452d262fa6Adam Powell } 310618cbea4e746196cbde43746706bec02e14b487bAdam Powell final float devX = devSumX / div; 311618cbea4e746196cbde43746706bec02e14b487bAdam Powell final float devY = devSumY / div; 312618cbea4e746196cbde43746706bec02e14b487bAdam Powell 313618cbea4e746196cbde43746706bec02e14b487bAdam Powell // Span is the average distance between touch points through the focal point; 314618cbea4e746196cbde43746706bec02e14b487bAdam Powell // i.e. the diameter of the circle with a radius of the average deviation from 315618cbea4e746196cbde43746706bec02e14b487bAdam Powell // the focal point. 316618cbea4e746196cbde43746706bec02e14b487bAdam Powell final float spanX = devX * 2; 317618cbea4e746196cbde43746706bec02e14b487bAdam Powell final float spanY = devY * 2; 318618cbea4e746196cbde43746706bec02e14b487bAdam Powell final float span = FloatMath.sqrt(spanX * spanX + spanY * spanY); 319618cbea4e746196cbde43746706bec02e14b487bAdam Powell 320618cbea4e746196cbde43746706bec02e14b487bAdam Powell // Dispatch begin/end events as needed. 321618cbea4e746196cbde43746706bec02e14b487bAdam Powell // If the configuration changes, notify the app to reset its current state by beginning 322618cbea4e746196cbde43746706bec02e14b487bAdam Powell // a fresh scale event stream. 32347ec2fb37046797bebc82b505a13c552021b9ff3Adam Powell final boolean wasInProgress = mInProgress; 32447ec2fb37046797bebc82b505a13c552021b9ff3Adam Powell mFocusX = focusX; 32547ec2fb37046797bebc82b505a13c552021b9ff3Adam Powell mFocusY = focusY; 326828e56ea6e8f4d5aa650052580f1f7873ad8296dAdam Powell if (mInProgress && (span < mMinSpan || configChanged)) { 327618cbea4e746196cbde43746706bec02e14b487bAdam Powell mListener.onScaleEnd(this); 328618cbea4e746196cbde43746706bec02e14b487bAdam Powell mInProgress = false; 32947ec2fb37046797bebc82b505a13c552021b9ff3Adam Powell mInitialSpan = span; 330618cbea4e746196cbde43746706bec02e14b487bAdam Powell } 331618cbea4e746196cbde43746706bec02e14b487bAdam Powell if (configChanged) { 332618cbea4e746196cbde43746706bec02e14b487bAdam Powell mPrevSpanX = mCurrSpanX = spanX; 333618cbea4e746196cbde43746706bec02e14b487bAdam Powell mPrevSpanY = mCurrSpanY = spanY; 33447ec2fb37046797bebc82b505a13c552021b9ff3Adam Powell mInitialSpan = mPrevSpan = mCurrSpan = span; 335618cbea4e746196cbde43746706bec02e14b487bAdam Powell } 336b1861c3e89c3e869c95c5c01b78320a1dcef26adAdam Powell if (!mInProgress && span >= mMinSpan && 33747ec2fb37046797bebc82b505a13c552021b9ff3Adam Powell (wasInProgress || Math.abs(span - mInitialSpan) > mSpanSlop)) { 33847ec2fb37046797bebc82b505a13c552021b9ff3Adam Powell mPrevSpanX = mCurrSpanX = spanX; 33947ec2fb37046797bebc82b505a13c552021b9ff3Adam Powell mPrevSpanY = mCurrSpanY = spanY; 34047ec2fb37046797bebc82b505a13c552021b9ff3Adam Powell mPrevSpan = mCurrSpan = span; 341618cbea4e746196cbde43746706bec02e14b487bAdam Powell mInProgress = mListener.onScaleBegin(this); 342ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 343ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 344618cbea4e746196cbde43746706bec02e14b487bAdam Powell // Handle motion; focal point and span/scale factor are changing. 345618cbea4e746196cbde43746706bec02e14b487bAdam Powell if (action == MotionEvent.ACTION_MOVE) { 346618cbea4e746196cbde43746706bec02e14b487bAdam Powell mCurrSpanX = spanX; 347618cbea4e746196cbde43746706bec02e14b487bAdam Powell mCurrSpanY = spanY; 348618cbea4e746196cbde43746706bec02e14b487bAdam Powell mCurrSpan = span; 349618cbea4e746196cbde43746706bec02e14b487bAdam Powell 350618cbea4e746196cbde43746706bec02e14b487bAdam Powell boolean updatePrev = true; 351618cbea4e746196cbde43746706bec02e14b487bAdam Powell if (mInProgress) { 352618cbea4e746196cbde43746706bec02e14b487bAdam Powell updatePrev = mListener.onScale(this); 353618cbea4e746196cbde43746706bec02e14b487bAdam Powell } 354e33cef8037cb87386e17bcf8701a47452d262fa6Adam Powell 355618cbea4e746196cbde43746706bec02e14b487bAdam Powell if (updatePrev) { 356618cbea4e746196cbde43746706bec02e14b487bAdam Powell mPrevSpanX = mCurrSpanX; 357618cbea4e746196cbde43746706bec02e14b487bAdam Powell mPrevSpanY = mCurrSpanY; 358618cbea4e746196cbde43746706bec02e14b487bAdam Powell mPrevSpan = mCurrSpan; 359d0197f3669efda060c7ee2069ff41bd970fd6d9cAdam Powell } 360d0197f3669efda060c7ee2069ff41bd970fd6d9cAdam Powell } 361d0197f3669efda060c7ee2069ff41bd970fd6d9cAdam Powell 362618cbea4e746196cbde43746706bec02e14b487bAdam Powell return true; 363ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 364ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 365ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell /** 366618cbea4e746196cbde43746706bec02e14b487bAdam Powell * Returns {@code true} if a scale gesture is in progress. 367ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell */ 368ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public boolean isInProgress() { 369618cbea4e746196cbde43746706bec02e14b487bAdam Powell return mInProgress; 370ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 371ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 372ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell /** 373ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * Get the X coordinate of the current gesture's focal point. 374618cbea4e746196cbde43746706bec02e14b487bAdam Powell * If a gesture is in progress, the focal point is between 375618cbea4e746196cbde43746706bec02e14b487bAdam Powell * each of the pointers forming the gesture. 376618cbea4e746196cbde43746706bec02e14b487bAdam Powell * 377ab905c87b7324d15715b78eaae7ef8558ad3bd10Adam Powell * If {@link #isInProgress()} would return false, the result of this 378ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * function is undefined. 37947c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 380ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * @return X coordinate of the focal point in pixels. 381ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell */ 382ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public float getFocusX() { 383ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell return mFocusX; 384ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 385ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 386ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell /** 387ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * Get the Y coordinate of the current gesture's focal point. 388618cbea4e746196cbde43746706bec02e14b487bAdam Powell * If a gesture is in progress, the focal point is between 389618cbea4e746196cbde43746706bec02e14b487bAdam Powell * each of the pointers forming the gesture. 390618cbea4e746196cbde43746706bec02e14b487bAdam Powell * 391ab905c87b7324d15715b78eaae7ef8558ad3bd10Adam Powell * If {@link #isInProgress()} would return false, the result of this 392ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * function is undefined. 39347c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 394ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * @return Y coordinate of the focal point in pixels. 395ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell */ 396ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public float getFocusY() { 397ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell return mFocusY; 398ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 399ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 400ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell /** 401618cbea4e746196cbde43746706bec02e14b487bAdam Powell * Return the average distance between each of the pointers forming the 402618cbea4e746196cbde43746706bec02e14b487bAdam Powell * gesture in progress through the focal point. 40347c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 404ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * @return Distance between pointers in pixels. 405ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell */ 406ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public float getCurrentSpan() { 407618cbea4e746196cbde43746706bec02e14b487bAdam Powell return mCurrSpan; 408ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 409ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 410ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell /** 411618cbea4e746196cbde43746706bec02e14b487bAdam Powell * Return the average X distance between each of the pointers forming the 412618cbea4e746196cbde43746706bec02e14b487bAdam Powell * gesture in progress through the focal point. 41347c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 41447c41e807e36999e4d0d2072e41a82bc45655ff2Erik * @return Distance between pointers in pixels. 41547c41e807e36999e4d0d2072e41a82bc45655ff2Erik */ 41647c41e807e36999e4d0d2072e41a82bc45655ff2Erik public float getCurrentSpanX() { 417618cbea4e746196cbde43746706bec02e14b487bAdam Powell return mCurrSpanX; 41847c41e807e36999e4d0d2072e41a82bc45655ff2Erik } 41947c41e807e36999e4d0d2072e41a82bc45655ff2Erik 42047c41e807e36999e4d0d2072e41a82bc45655ff2Erik /** 421618cbea4e746196cbde43746706bec02e14b487bAdam Powell * Return the average Y distance between each of the pointers forming the 422618cbea4e746196cbde43746706bec02e14b487bAdam Powell * gesture in progress through the focal point. 42347c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 42447c41e807e36999e4d0d2072e41a82bc45655ff2Erik * @return Distance between pointers in pixels. 42547c41e807e36999e4d0d2072e41a82bc45655ff2Erik */ 42647c41e807e36999e4d0d2072e41a82bc45655ff2Erik public float getCurrentSpanY() { 427618cbea4e746196cbde43746706bec02e14b487bAdam Powell return mCurrSpanY; 42847c41e807e36999e4d0d2072e41a82bc45655ff2Erik } 42947c41e807e36999e4d0d2072e41a82bc45655ff2Erik 43047c41e807e36999e4d0d2072e41a82bc45655ff2Erik /** 431618cbea4e746196cbde43746706bec02e14b487bAdam Powell * Return the previous average distance between each of the pointers forming the 432618cbea4e746196cbde43746706bec02e14b487bAdam Powell * gesture in progress through the focal point. 43347c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 434ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * @return Previous distance between pointers in pixels. 435ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell */ 436ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public float getPreviousSpan() { 437618cbea4e746196cbde43746706bec02e14b487bAdam Powell return mPrevSpan; 438ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 439ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell 440ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell /** 441618cbea4e746196cbde43746706bec02e14b487bAdam Powell * Return the previous average X distance between each of the pointers forming the 442618cbea4e746196cbde43746706bec02e14b487bAdam Powell * gesture in progress through the focal point. 44347c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 44447c41e807e36999e4d0d2072e41a82bc45655ff2Erik * @return Previous distance between pointers in pixels. 44547c41e807e36999e4d0d2072e41a82bc45655ff2Erik */ 44647c41e807e36999e4d0d2072e41a82bc45655ff2Erik public float getPreviousSpanX() { 447618cbea4e746196cbde43746706bec02e14b487bAdam Powell return mPrevSpanX; 44847c41e807e36999e4d0d2072e41a82bc45655ff2Erik } 44947c41e807e36999e4d0d2072e41a82bc45655ff2Erik 45047c41e807e36999e4d0d2072e41a82bc45655ff2Erik /** 451618cbea4e746196cbde43746706bec02e14b487bAdam Powell * Return the previous average Y distance between each of the pointers forming the 452618cbea4e746196cbde43746706bec02e14b487bAdam Powell * gesture in progress through the focal point. 45347c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 45447c41e807e36999e4d0d2072e41a82bc45655ff2Erik * @return Previous distance between pointers in pixels. 45547c41e807e36999e4d0d2072e41a82bc45655ff2Erik */ 45647c41e807e36999e4d0d2072e41a82bc45655ff2Erik public float getPreviousSpanY() { 457618cbea4e746196cbde43746706bec02e14b487bAdam Powell return mPrevSpanY; 45847c41e807e36999e4d0d2072e41a82bc45655ff2Erik } 45947c41e807e36999e4d0d2072e41a82bc45655ff2Erik 46047c41e807e36999e4d0d2072e41a82bc45655ff2Erik /** 461ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * Return the scaling factor from the previous scale event to the current 462ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * event. This value is defined as 463ab905c87b7324d15715b78eaae7ef8558ad3bd10Adam Powell * ({@link #getCurrentSpan()} / {@link #getPreviousSpan()}). 46447c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 465ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * @return The current scaling factor. 466ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell */ 467ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public float getScaleFactor() { 468618cbea4e746196cbde43746706bec02e14b487bAdam Powell return mPrevSpan > 0 ? mCurrSpan / mPrevSpan : 1; 469ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 47047c41e807e36999e4d0d2072e41a82bc45655ff2Erik 471ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell /** 472ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * Return the time difference in milliseconds between the previous 473ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * accepted scaling event and the current scaling event. 47447c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 475ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * @return Time difference since the last scaling event in milliseconds. 476ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell */ 477ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public long getTimeDelta() { 478618cbea4e746196cbde43746706bec02e14b487bAdam Powell return mCurrTime - mPrevTime; 479ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 48047c41e807e36999e4d0d2072e41a82bc45655ff2Erik 481ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell /** 482ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * Return the event time of the current event being processed. 48347c41e807e36999e4d0d2072e41a82bc45655ff2Erik * 484ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell * @return Current event time in milliseconds. 485ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell */ 486ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell public long getEventTime() { 487618cbea4e746196cbde43746706bec02e14b487bAdam Powell return mCurrTime; 488ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell } 489ae542ff055301a4c3c8a18e8da1739df3a771958Adam Powell} 490