package org.metalev.multitouch.controller;
/**
* MultiTouchController.java
* Source https://github.com/lukehutch/android-multitouch-controller/blob/master/MTController/src/org/metalev/multitouch/controller/MultiTouchController.java
*
* Author: Luke Hutchison (luke.hutch@mit.edu)
* Please drop me an email if you use this code so I can list your project here!
*
* Usage:
* <code>
* public class MyMTView extends View implements MultiTouchObjectCanvas<PinchWidgetType> {
*
* private MultiTouchController<PinchWidgetType> multiTouchController = new MultiTouchController<PinchWidgetType>(this);
*
* // Pass touch events to the MT controller
* public boolean onTouchEvent(MotionEvent event) {
* return multiTouchController.onTouchEvent(event);
* }
*
* // ... then implement the MultiTouchObjectCanvas interface here, see details in the comments of that interface.
* }
* </code>
*
* Changelog:
* 2010-06-09 v1.5.1 Some API changes to make it possible to selectively update or not update scale / rotation.
* Fixed anisotropic zoom. Cleaned up rotation code. Added more comments. Better var names. (LH)
* 2010-06-09 v1.4 Added ability to track pinch rotation (Mickael Despesse, author of "Face Frenzy") and anisotropic pinch-zoom (LH)
* 2010-06-09 v1.3.3 Bugfixes for Android-2.1; added optional debug info (LH)
* 2010-06-09 v1.3 Ported to Android-2.2 (handle ACTION_POINTER_* actions); fixed several bugs; refactoring; documentation (LH)
* 2010-05-17 v1.2.1 Dual-licensed under Apache and GPL licenses
* 2010-02-18 v1.2 Support for compilation under Android 1.5/1.6 using introspection (mmin, author of handyCalc)
* 2010-01-08 v1.1.1 Bugfixes to Cyanogen's patch that only showed up in more complex uses of controller (LH)
* 2010-01-06 v1.1 Modified for official level 5 MT API (Cyanogen)
* 2009-01-25 v1.0 Original MT controller, released for hacked G1 kernel (LH)
*
* TODO:
* - Add inertia (flick-pinch-zoom or flick-scroll)
* - Merge in Paul Bourke's "grab" support for single-finger drag of objects: git://github.com/brk3/android-multitouch-controller.git
* (Initial concern are the two lines of the form "newScale = mCurrXform.scale - 0.04f", and the line in pastThreshold() that says
* "if (newScale == mCurrXform.scale)" -- this doesn't look like a robust solution to convey state, by changing scale by a tiny
* amount, but maybe I'm not understanding the intent behind the code or its behavior).
*
* Known usages: see http://code.google.com/p/android-multitouch-controller/
*
* --
*
* Released under the MIT license (but please notify me if you use this code, so that I can give your project credit at
* http://code.google.com/p/android-multitouch-controller ).
*
* MIT license: http://www.opensource.org/licenses/MIT
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
import java.lang.reflect.Method;
import android.util.Log;
import android.view.MotionEvent;
/**
* A class that simplifies the implementation of multitouch in applications. Subclass this and read the fields here as needed in subclasses.
*
* @author Luke Hutchison
*/
public class MultiTouchController<T> {
/**
* Time in ms required after a change in event status (e.g. putting down or lifting off the second finger) before events actually do anything --
* helps eliminate noisy jumps that happen on change of status
*/
private static final long EVENT_SETTLE_TIME_INTERVAL = 20;
/**
* The biggest possible abs val of the change in x or y between multitouch events (larger dx/dy events are ignored) -- helps eliminate jumps in
* pointer position on finger 2 up/down.
*/
private static final float MAX_MULTITOUCH_POS_JUMP_SIZE = 30.0f;
/**
* The biggest possible abs val of the change in multitouchWidth or multitouchHeight between multitouch events (larger-jump events are ignored) --
* helps eliminate jumps in pointer position on finger 2 up/down.
*/
private static final float MAX_MULTITOUCH_DIM_JUMP_SIZE = 40.0f;
/** The smallest possible distance between multitouch points (used to avoid div-by-zero errors and display glitches) */
private static final float MIN_MULTITOUCH_SEPARATION = 30.0f;
/** The max number of touch points that can be present on the screen at once */
public static final int MAX_TOUCH_POINTS = 20;
/** Generate tons of log entries for debugging */
public static final boolean DEBUG = false;
// ----------------------------------------------------------------------------------------------------------------------
MultiTouchObjectCanvas<T> objectCanvas;
/** The current touch point */
private PointInfo mCurrPt;
/** The previous touch point */
private PointInfo mPrevPt;
/** Fields extracted from mCurrPt */
private float mCurrPtX, mCurrPtY, mCurrPtDiam, mCurrPtWidth, mCurrPtHeight, mCurrPtAng;
/**
* Extract fields from mCurrPt, respecting the update* fields of mCurrPt. This just avoids code duplication. I hate that Java doesn't support
* higher-order functions, tuples or multiple return values from functions.
*/
private void extractCurrPtInfo() {
// Get new drag/pinch params. Only read multitouch fields that are needed,
// to avoid unnecessary computation (diameter and angle are expensive operations).
mCurrPtX = mCurrPt.getX();
mCurrPtY = mCurrPt.getY();
mCurrPtDiam = Math.max(MIN_MULTITOUCH_SEPARATION * .71f, !mCurrXform.updateScale ? 0.0f : mCurrPt.getMultiTouchDiameter());
mCurrPtWidth = Math.max(MIN_MULTITOUCH_SEPARATION, !mCurrXform.updateScaleXY ? 0.0f : mCurrPt.getMultiTouchWidth());
mCurrPtHeight = Math.max(MIN_MULTITOUCH_SEPARATION, !mCurrXform.updateScaleXY ? 0.0f : mCurrPt.getMultiTouchHeight());
mCurrPtAng = !mCurrXform.updateAngle ? 0.0f : mCurrPt.getMultiTouchAngle();
}
// ----------------------------------------------------------------------------------------------------------------------
/** Whether to handle single-touch events/drags before multi-touch is initiated or not; if not, they are handled by subclasses */
private boolean handleSingleTouchEvents;
/** The object being dragged/stretched */
private T selectedObject = null;
/** Current position and scale of the dragged object */
private PositionAndScale mCurrXform = new PositionAndScale();
/** Drag/pinch start time and time to ignore spurious events until (to smooth over event noise) */
private long mSettleStartTime, mSettleEndTime;
/** Conversion from object coords to screen coords */
private float startPosX, startPosY;
/** Conversion between scale and width, and object angle and start pinch angle */
private float startScaleOverPinchDiam, startAngleMinusPinchAngle;
/** Conversion between X scale and width, and Y scale and height */
private float startScaleXOverPinchWidth, startScaleYOverPinchHeight;
// ----------------------------------------------------------------------------------------------------------------------
/** No touch points down. */
private static final int MODE_NOTHING = 0;
/** One touch point down, dragging an object. */
private static final int MODE_DRAG = 1;
/** Two or more touch points down, stretching/rotating an object using the first two touch points. */
private static final int MODE_PINCH = 2;
/** Current drag mode */
private int mMode = MODE_NOTHING;
// ----------------------------------------------------------------------------------------------------------------------
/** Constructor that sets handleSingleTouchEvents to true */
public MultiTouchController(MultiTouchObjectCanvas<T> objectCanvas) {
this(objectCanvas, true);
}
/** Full constructor */
public MultiTouchController(MultiTouchObjectCanvas<T> objectCanvas, boolean handleSingleTouchEvents) {
this.mCurrPt = new PointInfo();
this.mPrevPt = new PointInfo();
this.handleSingleTouchEvents = handleSingleTouchEvents;
this.objectCanvas = objectCanvas;
}
// ------------------------------------------------------------------------------------
/**
* Whether to handle single-touch events/drags before multi-touch is initiated or not; if not, they are handled by subclasses. Default: true
*/
protected void setHandleSingleTouchEvents(boolean handleSingleTouchEvents) {
this.handleSingleTouchEvents = handleSingleTouchEvents;
}
/**
* Whether to handle single-touch events/drags before multi-touch is initiated or not; if not, they are handled by subclasses. Default: true
*/
protected boolean getHandleSingleTouchEvents() {
return handleSingleTouchEvents;
}
// ------------------------------------------------------------------------------------
public static final boolean multiTouchSupported;
private static Method m_getPointerCount;
private static Method m_getPointerId;
private static Method m_getPressure;
private static Method m_getHistoricalX;
private static Method m_getHistoricalY;
private static Method m_getHistoricalPressure;
private static Method m_getX;
private static Method m_getY;
private static int ACTION_POINTER_UP = 6;
private static int ACTION_POINTER_INDEX_SHIFT = 8;
static {
boolean succeeded = false;
try {
// Android 2.0.1 stuff:
m_getPointerCount = MotionEvent.class.getMethod("getPointerCount");
m_getPointerId = MotionEvent.class.getMethod("getPointerId", Integer.TYPE);
m_getPressure = MotionEvent.class.getMethod("getPressure", Integer.TYPE);
m_getHistoricalX = MotionEvent.class.getMethod("getHistoricalX", Integer.TYPE, Integer.TYPE);
m_getHistoricalY = MotionEvent.class.getMethod("getHistoricalY", Integer.TYPE, Integer.TYPE);
m_getHistoricalPressure = MotionEvent.class.getMethod("getHistoricalPressure", Integer.TYPE, Integer.TYPE);
m_getX = MotionEvent.class.getMethod("getX", Integer.TYPE);
m_getY = MotionEvent.class.getMethod("getY", Integer.TYPE);
succeeded = true;
} catch (Exception e) {
Log.e("MultiTouchController", "static initializer failed", e);
}
multiTouchSupported = succeeded;
if (multiTouchSupported) {
// Android 2.2+ stuff (the original Android 2.2 consts are declared above,
// and these actions aren't used previous to Android 2.2):
try {
ACTION_POINTER_UP = MotionEvent.class.getField("ACTION_POINTER_UP").getInt(null);
ACTION_POINTER_INDEX_SHIFT = MotionEvent.class.getField("ACTION_POINTER_INDEX_SHIFT").getInt(null);
} catch (Exception e) {
}
}
}
// ------------------------------------------------------------------------------------
private static final float[] xVals = new float[MAX_TOUCH_POINTS];
private static final float[] yVals = new float[MAX_TOUCH_POINTS];
private static final float[] pressureVals = new float[MAX_TOUCH_POINTS];
private static final int[] pointerIds = new int[MAX_TOUCH_POINTS];
/** Process incoming touch events */
@SuppressWarnings("unused")
public boolean onTouchEvent(MotionEvent event) {
try {
int pointerCount = multiTouchSupported ? (Integer) m_getPointerCount.invoke(event) : 1;
if (DEBUG)
Log.i("MultiTouch", "Got here 1 - " + multiTouchSupported + " " + mMode + " " + handleSingleTouchEvents + " " + pointerCount);
if (mMode == MODE_NOTHING && !handleSingleTouchEvents && pointerCount == 1)
// Not handling initial single touch events, just pass them on
return false;
if (DEBUG)
Log.i("MultiTouch", "Got here 2");
// Handle history first (we sometimes get history with ACTION_MOVE events)
int action = event.getAction();
int histLen = event.getHistorySize() / pointerCount;
for (int histIdx = 0; histIdx <= histLen; histIdx++) {
// Read from history entries until histIdx == histLen, then read from current event
boolean processingHist = histIdx < histLen;
if (!multiTouchSupported || pointerCount == 1) {
// Use single-pointer methods -- these are needed as a special case (for some weird reason) even if
// multitouch is supported but there's only one touch point down currently -- event.getX(0) etc. throw
// an exception if there's only one point down.
if (DEBUG)
Log.i("MultiTouch", "Got here 3");
xVals[0] = processingHist ? event.getHistoricalX(histIdx) : event.getX();
yVals[0] = processingHist ? event.getHistoricalY(histIdx) : event.getY();
pressureVals[0] = processingHist ? event.getHistoricalPressure(histIdx) : event.getPressure();
} else {
// Read x, y and pressure of each pointer
if (DEBUG)
Log.i("MultiTouch", "Got here 4");
int numPointers = Math.min(pointerCount, MAX_TOUCH_POINTS);
if (DEBUG && pointerCount > MAX_TOUCH_POINTS)
Log.i("MultiTouch", "Got more pointers than MAX_TOUCH_POINTS");
for (int ptrIdx = 0; ptrIdx < numPointers; ptrIdx++) {
int ptrId = (Integer) m_getPointerId.invoke(event, ptrIdx);
pointerIds[ptrIdx] = ptrId;
// N.B. if pointerCount == 1, then the following methods throw an array index out of range exception,
// and the code above is therefore required not just for Android 1.5/1.6 but also for when there is
// only one touch point on the screen -- pointlessly inconsistent :(
xVals[ptrIdx] = (Float) (processingHist ? m_getHistoricalX.invoke(event, ptrIdx, histIdx) : m_getX.invoke(event, ptrIdx));
yVals[ptrIdx] = (Float) (processingHist ? m_getHistoricalY.invoke(event, ptrIdx, histIdx) : m_getY.invoke(event, ptrIdx));
pressureVals[ptrIdx] = (Float) (processingHist ? m_getHistoricalPressure.invoke(event, ptrIdx, histIdx) : m_getPressure
.invoke(event, ptrIdx));
}
}
// Decode event
decodeTouchEvent(pointerCount, xVals, yVals, pressureVals, pointerIds, //
/* action = */processingHist ? MotionEvent.ACTION_MOVE : action, //
/* down = */processingHist ? true : action != MotionEvent.ACTION_UP //
&& (action & ((1 << ACTION_POINTER_INDEX_SHIFT) - 1)) != ACTION_POINTER_UP //
&& action != MotionEvent.ACTION_CANCEL, //
processingHist ? event.getHistoricalEventTime(histIdx) : event.getEventTime());
}
return true;
} catch (Exception e) {
// In case any of the introspection stuff fails (it shouldn't)
Log.e("MultiTouchController", "onTouchEvent() failed", e);
return false;
}
}
private void decodeTouchEvent(int pointerCount, float[] x, float[] y, float[] pressure, int[] pointerIds, int action, boolean down, long eventTime) {
if (DEBUG)
Log.i("MultiTouch", "Got here 5 - " + pointerCount + " " + action + " " + down);
// Swap curr/prev points
PointInfo tmp = mPrevPt;
mPrevPt = mCurrPt;
mCurrPt = tmp;
// Overwrite old prev point
mCurrPt.set(pointerCount, x, y, pressure, pointerIds, action, down, eventTime);
multiTouchController();
}
// ------------------------------------------------------------------------------------
/** Start dragging/pinching, or reset drag/pinch to current point if something goes out of range */
private void anchorAtThisPositionAndScale() {
if (DEBUG)
Log.i("MulitTouch", "anchorAtThisPositionAndScale()");
if (selectedObject == null)
return;
// Get selected object's current position and scale
objectCanvas.getPositionAndScale(selectedObject, mCurrXform);
// Figure out the object coords of the drag start point's screen coords.
// All stretching should be around this point in object-coord-space.
// Also figure out out ratio between object scale factor and multitouch
// diameter at beginning of drag; same for angle and optional anisotropic
// scale.
float currScaleInv = 1.0f / (!mCurrXform.updateScale ? 1.0f : mCurrXform.scale == 0.0f ? 1.0f : mCurrXform.scale);
extractCurrPtInfo();
startPosX = (mCurrPtX - mCurrXform.xOff) * currScaleInv;
startPosY = (mCurrPtY - mCurrXform.yOff) * currScaleInv;
startScaleOverPinchDiam = mCurrXform.scale / mCurrPtDiam;
startScaleXOverPinchWidth = mCurrXform.scaleX / mCurrPtWidth;
startScaleYOverPinchHeight = mCurrXform.scaleY / mCurrPtHeight;
startAngleMinusPinchAngle = mCurrXform.angle - mCurrPtAng;
}
/** Drag/stretch/rotate the selected object using the current touch position(s) relative to the anchor position(s). */
private void performDragOrPinch() {
// Don't do anything if we're not dragging anything
if (selectedObject == null)
return;
// Calc new position of dragged object
float currScale = !mCurrXform.updateScale ? 1.0f : mCurrXform.scale == 0.0f ? 1.0f : mCurrXform.scale;
extractCurrPtInfo();
float newPosX = mCurrPtX - startPosX * currScale;
float newPosY = mCurrPtY - startPosY * currScale;
float newScale = startScaleOverPinchDiam * mCurrPtDiam;
float newScaleX = startScaleXOverPinchWidth * mCurrPtWidth;
float newScaleY = startScaleYOverPinchHeight * mCurrPtHeight;
float newAngle = startAngleMinusPinchAngle + mCurrPtAng;
// Set the new obj coords, scale, and angle as appropriate (notifying the subclass of the change).
mCurrXform.set(newPosX, newPosY, newScale, newScaleX, newScaleY, newAngle);
boolean success = objectCanvas.setPositionAndScale(selectedObject, mCurrXform, mCurrPt);
if (!success)
; // If we could't set those params, do nothing currently
}
/** Indicate if we are in the middle of a pinch action or not. osmdroid addon*/
public boolean isPinching() {
return mMode == MODE_PINCH;
}
/**
* State-based controller for tracking switches between no-touch, single-touch and multi-touch situations. Includes logic for cleaning up the
* event stream, as events around touch up/down are noisy at least on early Synaptics sensors.
*/
private void multiTouchController() {
if (DEBUG)
Log.i("MultiTouch", "Got here 6 - " + mMode + " " + mCurrPt.getNumTouchPoints() + " " + mCurrPt.isDown() + mCurrPt.isMultiTouch());
switch (mMode) {
case MODE_NOTHING:
if (DEBUG)
Log.i("MultiTouch", "MODE_NOTHING");
// Not doing anything currently
if (mCurrPt.isDown()) {
// Start a new single-point drag
selectedObject = objectCanvas.getDraggableObjectAtPoint(mCurrPt);
if (selectedObject != null) {
// Started a new single-point drag
mMode = MODE_DRAG;
objectCanvas.selectObject(selectedObject, mCurrPt);
anchorAtThisPositionAndScale();
// Don't need any settling time if just placing one finger, there is no noise
mSettleStartTime = mSettleEndTime = mCurrPt.getEventTime();
}
}
break;
case MODE_DRAG:
if (DEBUG)
Log.i("MultiTouch", "MODE_DRAG");
// Currently in a single-point drag
if (!mCurrPt.isDown()) {
// First finger was released, stop dragging
mMode = MODE_NOTHING;
objectCanvas.selectObject((selectedObject = null), mCurrPt);
} else if (mCurrPt.isMultiTouch()) {
// Point 1 was already down and point 2 was just placed down
mMode = MODE_PINCH;
// Restart the drag with the new drag position (that is at the midpoint between the touchpoints)
anchorAtThisPositionAndScale();
// Need to let events settle before moving things, to help with event noise on touchdown
mSettleStartTime = mCurrPt.getEventTime();
mSettleEndTime = mSettleStartTime + EVENT_SETTLE_TIME_INTERVAL;
} else {
// Point 1 is still down and point 2 did not change state, just do single-point drag to new location
if (mCurrPt.getEventTime() < mSettleEndTime) {
// Ignore the first few events if we just stopped stretching, because if finger 2 was kept down while
// finger 1 is lifted, then point 1 gets mapped to finger 2. Restart the drag from the new position.
anchorAtThisPositionAndScale();
} else {
// Keep dragging, move to new point
performDragOrPinch();
}
}
break;
case MODE_PINCH:
if (DEBUG)
Log.i("MultiTouch", "MODE_PINCH");
// Two-point pinch-scale/rotate/translate
if (!mCurrPt.isMultiTouch() || !mCurrPt.isDown()) {
// Dropped one or both points, stop stretching
if (!mCurrPt.isDown()) {
// Dropped both points, go back to doing nothing
mMode = MODE_NOTHING;
objectCanvas.selectObject((selectedObject = null), mCurrPt);
} else {
// Just dropped point 2, downgrade to a single-point drag
mMode = MODE_DRAG;
// Restart the pinch with the single-finger position
anchorAtThisPositionAndScale();
// Ignore the first few events after the drop, in case we dropped finger 1 and left finger 2 down
mSettleStartTime = mCurrPt.getEventTime();
mSettleEndTime = mSettleStartTime + EVENT_SETTLE_TIME_INTERVAL;
}
} else {
// Still pinching
if (Math.abs(mCurrPt.getX() - mPrevPt.getX()) > MAX_MULTITOUCH_POS_JUMP_SIZE
|| Math.abs(mCurrPt.getY() - mPrevPt.getY()) > MAX_MULTITOUCH_POS_JUMP_SIZE
|| Math.abs(mCurrPt.getMultiTouchWidth() - mPrevPt.getMultiTouchWidth()) * .5f > MAX_MULTITOUCH_DIM_JUMP_SIZE
|| Math.abs(mCurrPt.getMultiTouchHeight() - mPrevPt.getMultiTouchHeight()) * .5f > MAX_MULTITOUCH_DIM_JUMP_SIZE) {
// Jumped too far, probably event noise, reset and ignore events for a bit
anchorAtThisPositionAndScale();
mSettleStartTime = mCurrPt.getEventTime();
mSettleEndTime = mSettleStartTime + EVENT_SETTLE_TIME_INTERVAL;
} else if (mCurrPt.eventTime < mSettleEndTime) {
// Events have not yet settled, reset
anchorAtThisPositionAndScale();
} else {
// Stretch to new position and size
performDragOrPinch();
}
}
break;
}
if (DEBUG)
Log.i("MultiTouch", "Got here 7 - " + mMode + " " + mCurrPt.getNumTouchPoints() + " " + mCurrPt.isDown() + mCurrPt.isMultiTouch());
}
public int getMode() {
return mMode;
}
/** A class that packages up all MotionEvent information with all derived multitouch information (if available) */
public static class PointInfo {
// Multitouch information
private int numPoints;
private float[] xs = new float[MAX_TOUCH_POINTS];
private float[] ys = new float[MAX_TOUCH_POINTS];
private float[] pressures = new float[MAX_TOUCH_POINTS];
private int[] pointerIds = new int[MAX_TOUCH_POINTS];
// Midpoint of pinch operations
private float xMid, yMid, pressureMid;
// Width/diameter/angle of pinch operations
private float dx, dy, diameter, diameterSq, angle;
// Whether or not there is at least one finger down (isDown) and/or at least two fingers down (isMultiTouch)
private boolean isDown, isMultiTouch;
// Whether or not these fields have already been calculated, for caching purposes
private boolean diameterSqIsCalculated, diameterIsCalculated, angleIsCalculated;
// Event action code and event time
private int action;
private long eventTime;
// -------------------------------------------------------------------------------------------------------------------------------------------
/** Set all point info */
private void set(int numPoints, float[] x, float[] y, float[] pressure, int[] pointerIds, int action, boolean isDown, long eventTime) {
if (DEBUG)
Log.i("MultiTouch", "Got here 8 - " + +numPoints + " " + x[0] + " " + y[0] + " " + (numPoints > 1 ? x[1] : x[0]) + " "
+ (numPoints > 1 ? y[1] : y[0]) + " " + action + " " + isDown);
this.eventTime = eventTime;
this.action = action;
this.numPoints = numPoints;
for (int i = 0; i < numPoints; i++) {
this.xs[i] = x[i];
this.ys[i] = y[i];
this.pressures[i] = pressure[i];
this.pointerIds[i] = pointerIds[i];
}
this.isDown = isDown;
this.isMultiTouch = numPoints >= 2;
if (isMultiTouch) {
xMid = (x[0] + x[1]) * .5f;
yMid = (y[0] + y[1]) * .5f;
pressureMid = (pressure[0] + pressure[1]) * .5f;
dx = Math.abs(x[1] - x[0]);
dy = Math.abs(y[1] - y[0]);
} else {
// Single-touch event
xMid = x[0];
yMid = y[0];
pressureMid = pressure[0];
dx = dy = 0.0f;
}
// Need to re-calculate the expensive params if they're needed
diameterSqIsCalculated = diameterIsCalculated = angleIsCalculated = false;
}
/**
* Copy all fields from one PointInfo class to another. PointInfo objects are volatile so you should use this if you want to keep track of the
* last touch event in your own code.
*/
public void set(PointInfo other) {
this.numPoints = other.numPoints;
for (int i = 0; i < numPoints; i++) {
this.xs[i] = other.xs[i];
this.ys[i] = other.ys[i];
this.pressures[i] = other.pressures[i];
this.pointerIds[i] = other.pointerIds[i];
}
this.xMid = other.xMid;
this.yMid = other.yMid;
this.pressureMid = other.pressureMid;
this.dx = other.dx;
this.dy = other.dy;
this.diameter = other.diameter;
this.diameterSq = other.diameterSq;
this.angle = other.angle;
this.isDown = other.isDown;
this.action = other.action;
this.isMultiTouch = other.isMultiTouch;
this.diameterIsCalculated = other.diameterIsCalculated;
this.diameterSqIsCalculated = other.diameterSqIsCalculated;
this.angleIsCalculated = other.angleIsCalculated;
this.eventTime = other.eventTime;
}
// -------------------------------------------------------------------------------------------------------------------------------------------
/** True if number of touch points greater than or equal to 2. */
public boolean isMultiTouch() {
return isMultiTouch;
}
/** Difference between x coords of touchpoint 0 and 1. */
public float getMultiTouchWidth() {
return isMultiTouch ? dx : 0.0f;
}
/** Difference between y coords of touchpoint 0 and 1. */
public float getMultiTouchHeight() {
return isMultiTouch ? dy : 0.0f;
}
/** Fast integer sqrt, by Jim Ulery. Much faster than Math.sqrt() for integers. */
private int julery_isqrt(int val) {
int temp, g = 0, b = 0x8000, bshft = 15;
do {
if (val >= (temp = (((g << 1) + b) << bshft--))) {
g += b;
val -= temp;
}
} while ((b >>= 1) > 0);
return g;
}
/** Calculate the squared diameter of the multitouch event, and cache it. Use this if you don't need to perform the sqrt. */
public float getMultiTouchDiameterSq() {
if (!diameterSqIsCalculated) {
diameterSq = (isMultiTouch ? dx * dx + dy * dy : 0.0f);
diameterSqIsCalculated = true;
}
return diameterSq;
}
/** Calculate the diameter of the multitouch event, and cache it. Uses fast int sqrt but gives accuracy to 1/16px. */
public float getMultiTouchDiameter() {
if (!diameterIsCalculated) {
if (!isMultiTouch) {
diameter = 0.0f;
} else {
// Get 1/16 pixel's worth of subpixel accuracy, works on screens up to 2048x2048
// before we get overflow (at which point you can reduce or eliminate subpix
// accuracy, or use longs in julery_isqrt())
float diamSq = getMultiTouchDiameterSq();
diameter = (diamSq == 0.0f ? 0.0f : (float) julery_isqrt((int) (256 * diamSq)) / 16.0f);
// Make sure diameter is never less than dx or dy, for trig purposes
if (diameter < dx)
diameter = dx;
if (diameter < dy)
diameter = dy;
}
diameterIsCalculated = true;
}
return diameter;
}
/**
* Calculate the angle of a multitouch event, and cache it. Actually gives the smaller of the two angles between the x axis and the line
* between the two touchpoints, so range is [0,Math.PI/2]. Uses Math.atan2().
*/
public float getMultiTouchAngle() {
if (!angleIsCalculated) {
if (!isMultiTouch)
angle = 0.0f;
else
angle = (float) Math.atan2(ys[1] - ys[0], xs[1] - xs[0]);
angleIsCalculated = true;
}
return angle;
}
// -------------------------------------------------------------------------------------------------------------------------------------------
/** Return the total number of touch points */
public int getNumTouchPoints() {
return numPoints;
}
/** Return the X coord of the first touch point if there's only one, or the midpoint between first and second touch points if two or more. */
public float getX() {
return xMid;
}
/** Return the array of X coords -- only the first getNumTouchPoints() of these is defined. */
public float[] getXs() {
return xs;
}
/** Return the X coord of the first touch point if there's only one, or the midpoint between first and second touch points if two or more. */
public float getY() {
return yMid;
}
/** Return the array of Y coords -- only the first getNumTouchPoints() of these is defined. */
public float[] getYs() {
return ys;
}
/**
* Return the array of pointer ids -- only the first getNumTouchPoints() of these is defined. These don't have to be all the numbers from 0 to
* getNumTouchPoints()-1 inclusive, numbers can be skipped if a finger is lifted and the touch sensor is capable of detecting that that
* particular touch point is no longer down. Note that a lot of sensors do not have this capability: when finger 1 is lifted up finger 2
* becomes the new finger 1. However in theory these IDs can correct for that. Convert back to indices using MotionEvent.findPointerIndex().
*/
public int[] getPointerIds() {
return pointerIds;
}
/** Return the pressure the first touch point if there's only one, or the average pressure of first and second touch points if two or more. */
public float getPressure() {
return pressureMid;
}
/** Return the array of pressures -- only the first getNumTouchPoints() of these is defined. */
public float[] getPressures() {
return pressures;
}
// -------------------------------------------------------------------------------------------------------------------------------------------
public boolean isDown() {
return isDown;
}
public int getAction() {
return action;
}
public long getEventTime() {
return eventTime;
}
}
// ------------------------------------------------------------------------------------
/**
* A class that is used to store scroll offsets and scale information for objects that are managed by the multitouch controller
*/
public static class PositionAndScale {
private float xOff, yOff, scale, scaleX, scaleY, angle;
private boolean updateScale, updateScaleXY, updateAngle;
/**
* Set position and optionally scale, anisotropic scale, and/or angle. Where if the corresponding "update" flag is set to false, the field's
* value will not be changed during a pinch operation. If the value is not being updated *and* the value is not used by the client
* application, then the value can just be zero. However if the value is not being updated but the value *is* being used by the client
* application, the value should still be specified and the update flag should be false (e.g. angle of the object being dragged should still
* be specified even if the program is in "resize" mode rather than "rotate" mode).
*/
public void set(float xOff, float yOff, boolean updateScale, float scale, boolean updateScaleXY, float scaleX, float scaleY,
boolean updateAngle, float angle) {
this.xOff = xOff;
this.yOff = yOff;
this.updateScale = updateScale;
this.scale = scale == 0.0f ? 1.0f : scale;
this.updateScaleXY = updateScaleXY;
this.scaleX = scaleX == 0.0f ? 1.0f : scaleX;
this.scaleY = scaleY == 0.0f ? 1.0f : scaleY;
this.updateAngle = updateAngle;
this.angle = angle;
}
/** Set position and optionally scale, anisotropic scale, and/or angle, without changing the "update" flags. */
protected void set(float xOff, float yOff, float scale, float scaleX, float scaleY, float angle) {
this.xOff = xOff;
this.yOff = yOff;
this.scale = scale == 0.0f ? 1.0f : scale;
this.scaleX = scaleX == 0.0f ? 1.0f : scaleX;
this.scaleY = scaleY == 0.0f ? 1.0f : scaleY;
this.angle = angle;
}
public float getXOff() {
return xOff;
}
public float getYOff() {
return yOff;
}
public float getScale() {
return !updateScale ? 1.0f : scale;
}
/** Included in case you want to support anisotropic scaling */
public float getScaleX() {
return !updateScaleXY ? 1.0f : scaleX;
}
/** Included in case you want to support anisotropic scaling */
public float getScaleY() {
return !updateScaleXY ? 1.0f : scaleY;
}
public float getAngle() {
return !updateAngle ? 0.0f : angle;
}
}
// ------------------------------------------------------------------------------------
public static interface MultiTouchObjectCanvas<T> {
/**
* See if there is a draggable object at the current point. Returns the object at the point, or null if nothing to drag. To start a multitouch
* drag/stretch operation, this routine must return some non-null reference to an object. This object is passed into the other methods in this
* interface when they are called.
*
* @param touchPoint
* The point being tested (in object coordinates). Return the topmost object under this point, or if dragging/stretching the whole
* canvas, just return a reference to the canvas.
* @return a reference to the object under the point being tested, or null to cancel the drag operation. If dragging/stretching the whole
* canvas (e.g. in a photo viewer), always return non-null, otherwise the stretch operation won't work.
*/
public T getDraggableObjectAtPoint(PointInfo touchPoint);
/**
* Get the screen coords of the dragged object's origin, and scale multiplier to convert screen coords to obj coords. The job of this routine
* is to call the .set() method on the passed PositionAndScale object to record the initial position and scale of the object (in object
* coordinates) before any dragging/stretching takes place.
*
* @param obj
* The object being dragged/stretched.
* @param objPosAndScaleOut
* Output parameter: You need to call objPosAndScaleOut.set() to record the current position and scale of obj.
*/
public void getPositionAndScale(T obj, PositionAndScale objPosAndScaleOut);
/**
* Callback to update the position and scale (in object coords) of the currently-dragged object.
*
* @param obj
* The object being dragged/stretched.
* @param newObjPosAndScale
* The new position and scale of the object, in object coordinates. Use this to move/resize the object before returning.
* @param touchPoint
* Info about the current touch point, including multitouch information and utilities to calculate and cache multitouch pinch
* diameter etc. (Note: touchPoint is volatile, if you want to keep any fields of touchPoint, you must copy them before the method
* body exits.)
* @return true if setting the position and scale of the object was successful, or false if the position or scale parameters are out of range
* for this object.
*/
public boolean setPositionAndScale(T obj, PositionAndScale newObjPosAndScale, PointInfo touchPoint);
/**
* Select an object at the given point. Can be used to bring the object to top etc. Only called when first touchpoint goes down, not when
* multitouch is initiated. Also called with null on touch-up.
*
* @param obj
* The object being selected by single-touch, or null on touch-up.
* @param touchPoint
* The current touch point.
*/
public void selectObject(T obj, PointInfo touchPoint);
}
}