gecko/embedding/android/ui/PanZoomController.java

616 lines
22 KiB
Java

/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Android code.
*
* The Initial Developer of the Original Code is Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2009-2010
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Patrick Walton <pcwalton@mozilla.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
package org.mozilla.gecko.ui;
import org.json.JSONObject;
import org.mozilla.gecko.gfx.IntSize;
import org.mozilla.gecko.gfx.LayerController;
import org.mozilla.gecko.GeckoApp;
import org.mozilla.gecko.GeckoAppShell;
import org.mozilla.gecko.GeckoEvent;
import android.graphics.PointF;
import android.graphics.RectF;
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import java.util.Timer;
import java.util.TimerTask;
/*
* Handles the kinetic scrolling and zooming physics for a layer controller.
*
* Many ideas are from Joe Hewitt's Scrollability:
* https://github.com/joehewitt/scrollability/
*/
public class PanZoomController
extends GestureDetector.SimpleOnGestureListener
implements ScaleGestureDetector.OnScaleGestureListener
{
private static final String LOGTAG = "GeckoPanZoomController";
private LayerController mController;
private static final float FRICTION = 0.97f;
// Animation stops if the velocity is below this value.
private static final float STOPPED_THRESHOLD = 4.0f;
// The percentage of the surface which can be overscrolled before it must snap back.
private static final float SNAP_LIMIT = 0.75f;
// The rate of deceleration when the surface has overscrolled.
private static final float OVERSCROLL_DECEL_RATE = 0.04f;
// The duration of animation when bouncing back.
private static final int SNAP_TIME = 150;
// The number of subdivisions we should consider when plotting the ease-out transition. Higher
// values make the animation more accurate, but slower to plot.
private static final int SUBDIVISION_COUNT = 1000;
// The distance the user has to pan before we recognize it as such (e.g. to avoid
// 1-pixel pans between the touch-down and touch-up of a click)
private static final float PAN_THRESHOLD = 4.0f;
private long mLastTimestamp;
private Timer mFlingTimer;
private Axis mX, mY;
/* The span at the first zoom event (in unzoomed page coordinates). */
private float mInitialZoomSpan;
/* The zoom focus at the first zoom event (in unzoomed page coordinates). */
private PointF mInitialZoomFocus;
private enum PanZoomState {
NOTHING, /* no touch-start events received */
FLING, /* all touches removed, but we're still scrolling page */
TOUCHING, /* one touch-start event received */
PANNING, /* touch-start followed by move */
PANNING_HOLD, /* in panning, but haven't moved.
* similar to TOUCHING but after starting a pan */
PINCHING, /* nth touch-start, where n > 1. this mode allows pan and zoom */
}
private PanZoomState mState;
public PanZoomController(LayerController controller) {
mController = controller;
mX = new Axis(); mY = new Axis();
mState = PanZoomState.NOTHING;
populatePositionAndLength();
}
public boolean onTouchEvent(MotionEvent event) {
switch (event.getActionMasked()) {
case MotionEvent.ACTION_DOWN: return onTouchStart(event);
case MotionEvent.ACTION_MOVE: return onTouchMove(event);
case MotionEvent.ACTION_UP: return onTouchEnd(event);
case MotionEvent.ACTION_CANCEL: return onTouchCancel(event);
default: return false;
}
}
public void geometryChanged() {
populatePositionAndLength();
}
/*
* Panning/scrolling
*/
private boolean onTouchStart(MotionEvent event) {
switch (mState) {
case FLING:
if (mFlingTimer != null) {
mFlingTimer.cancel();
mFlingTimer = null;
}
// fall through
case NOTHING:
mState = PanZoomState.TOUCHING;
mX.touchPos = event.getX(0);
mY.touchPos = event.getY(0);
return false;
case TOUCHING:
case PANNING:
case PANNING_HOLD:
case PINCHING:
mState = PanZoomState.PINCHING;
return false;
}
Log.e(LOGTAG, "Unhandled case " + mState + " in onTouchStart");
return false;
}
private boolean onTouchMove(MotionEvent event) {
switch (mState) {
case NOTHING:
case FLING:
// should never happen
Log.e(LOGTAG, "Received impossible touch move while in " + mState);
return false;
case TOUCHING:
mLastTimestamp = System.currentTimeMillis();
if (panDistance(event) < PAN_THRESHOLD)
return false;
// fall through
case PANNING_HOLD:
mState = PanZoomState.PANNING;
// fall through
case PANNING:
track(event, System.currentTimeMillis());
return true;
case PINCHING:
// scale gesture listener will handle this
return false;
}
Log.e(LOGTAG, "Unhandled case " + mState + " in onTouchMove");
return false;
}
private boolean onTouchEnd(MotionEvent event) {
switch (mState) {
case NOTHING:
case FLING:
// should never happen
Log.e(LOGTAG, "Received impossible touch end while in " + mState);
return false;
case TOUCHING:
mState = PanZoomState.NOTHING;
// TODO: send click to gecko
return false;
case PANNING:
case PANNING_HOLD:
mState = PanZoomState.FLING;
fling(System.currentTimeMillis());
return true;
case PINCHING:
int points = event.getPointerCount();
if (points == 1) {
// last touch up
mState = PanZoomState.NOTHING;
} else if (points == 2) {
int pointRemovedIndex = event.getActionIndex();
int pointRemainingIndex = 1 - pointRemovedIndex; // kind of a hack
mState = PanZoomState.TOUCHING;
mX.touchPos = event.getX(pointRemainingIndex);
mY.touchPos = event.getY(pointRemainingIndex);
} else {
// still pinching, do nothing
}
return true;
}
Log.e(LOGTAG, "Unhandled case " + mState + " in onTouchEnd");
return false;
}
private boolean onTouchCancel(MotionEvent event) {
mState = PanZoomState.NOTHING;
return false;
}
private float panDistance(MotionEvent move) {
float dx = mX.touchPos - move.getX(0);
float dy = mY.touchPos - move.getY(0);
return (float)Math.sqrt(dx * dx + dy * dy);
}
private void track(MotionEvent event, long timestamp) {
long timeStep = timestamp - mLastTimestamp;
mLastTimestamp = timestamp;
float zoomFactor = mController.getZoomFactor();
mX.velocity = (mX.touchPos - event.getX(0)) / zoomFactor;
mY.velocity = (mY.touchPos - event.getY(0)) / zoomFactor;
mX.touchPos = event.getX(0); mY.touchPos = event.getY(0);
if (stopped())
mState = PanZoomState.PANNING_HOLD;
mX.applyEdgeResistance(); mX.displace();
mY.applyEdgeResistance(); mY.displace();
updatePosition();
}
private void fling(long timestamp) {
long timeStep = timestamp - mLastTimestamp;
mLastTimestamp = timestamp;
if (mState != PanZoomState.FLING)
mX.velocity = mY.velocity = 0.0f;
mX.displace(); mY.displace();
updatePosition();
if (mFlingTimer != null)
mFlingTimer.cancel();
boolean stopped = stopped();
mX.startFling(stopped); mY.startFling(stopped);
mFlingTimer = new Timer();
mFlingTimer.scheduleAtFixedRate(new TimerTask() {
public void run() { mController.post(new FlingRunnable()); }
}, 0, 1000L/60L);
}
private boolean stopped() {
float absVelocity = (float)Math.sqrt(mX.velocity * mX.velocity +
mY.velocity * mY.velocity);
return absVelocity < STOPPED_THRESHOLD;
}
private void updatePosition() {
mController.scrollTo(mX.viewportPos, mY.viewportPos);
mController.notifyLayerClientOfGeometryChange();
}
// Populates the viewport info and length in the axes.
private void populatePositionAndLength() {
IntSize pageSize = mController.getPageSize();
RectF visibleRect = mController.getVisibleRect();
IntSize screenSize = mController.getScreenSize();
mX.setPageLength(pageSize.width);
mX.viewportPos = visibleRect.left;
mX.setViewportLength(visibleRect.width());
mY.setPageLength(pageSize.height);
mY.viewportPos = visibleRect.top;
mY.setViewportLength(visibleRect.height());
}
// The callback that performs the fling animation.
private class FlingRunnable implements Runnable {
public void run() {
populatePositionAndLength();
mX.advanceFling(); mY.advanceFling();
// If both X and Y axes are overscrolled, we have to wait until both axes have stopped
// to snap back to avoid a jarring effect.
boolean waitingToSnapX = mX.getFlingState() == Axis.FlingStates.WAITING_TO_SNAP;
boolean waitingToSnapY = mY.getFlingState() == Axis.FlingStates.WAITING_TO_SNAP;
if ((mX.getOverscroll() == Axis.Overscroll.PLUS || mX.getOverscroll() == Axis.Overscroll.MINUS) &&
(mY.getOverscroll() == Axis.Overscroll.PLUS || mY.getOverscroll() == Axis.Overscroll.MINUS))
{
if (waitingToSnapX && waitingToSnapY) {
mX.startSnap(); mY.startSnap();
}
} else {
if (waitingToSnapX)
mX.startSnap();
if (waitingToSnapY)
mY.startSnap();
}
mX.displace(); mY.displace();
updatePosition();
if (mX.getFlingState() == Axis.FlingStates.STOPPED &&
mY.getFlingState() == Axis.FlingStates.STOPPED) {
stop();
}
}
private void stop() {
mState = PanZoomState.NOTHING;
if (mFlingTimer != null) {
mFlingTimer.cancel();
mFlingTimer = null;
}
}
}
private float computeElasticity(float excess, float viewportLength) {
return 1.0f - excess / (viewportLength * SNAP_LIMIT);
}
private static boolean floatsApproxEqual(float a, float b) {
// account for floating point rounding errors
return Math.abs(a - b) < 1e-6;
}
// Physics information for one axis (X or Y).
private static class Axis {
public enum FlingStates {
STOPPED,
SCROLLING,
WAITING_TO_SNAP,
SNAPPING,
}
public enum Overscroll {
NONE,
MINUS, // Overscrolled in the negative direction
PLUS, // Overscrolled in the positive direction
BOTH, // Overscrolled in both directions (page is zoomed to smaller than screen)
}
public float touchPos; /* Position of the last touch. */
public float velocity; /* Velocity in this direction. */
private FlingStates mFlingState; /* The fling state we're in on this axis. */
private EaseOutAnimation mSnapAnim; /* The animation when the page is snapping back. */
/* These three need to be kept in sync with the layer controller. */
public float viewportPos;
private float mViewportLength;
private int mScreenLength;
private int mPageLength;
public FlingStates getFlingState() { return mFlingState; }
public void setViewportLength(float viewportLength) { mViewportLength = viewportLength; }
public void setScreenLength(int screenLength) { mScreenLength = screenLength; }
public void setPageLength(int pageLength) { mPageLength = pageLength; }
private float getViewportEnd() { return viewportPos + mViewportLength; }
public Overscroll getOverscroll() {
boolean minus = (viewportPos < 0.0f);
boolean plus = (getViewportEnd() > mPageLength);
if (minus && plus)
return Overscroll.BOTH;
else if (minus)
return Overscroll.MINUS;
else if (plus)
return Overscroll.PLUS;
else
return Overscroll.NONE;
}
// Returns the amount that the page has been overscrolled. If the page hasn't been
// overscrolled on this axis, returns 0.
private float getExcess() {
switch (getOverscroll()) {
case MINUS: return Math.min(-viewportPos, mPageLength - getViewportEnd());
case PLUS: return Math.min(viewportPos, getViewportEnd() - mPageLength);
default: return 0.0f;
}
}
// Applies resistance along the edges when tracking.
public void applyEdgeResistance() {
float excess = getExcess();
if (excess > 0.0f)
velocity *= SNAP_LIMIT - excess / mViewportLength;
}
public void startFling(boolean stopped) {
if (!stopped) {
mFlingState = FlingStates.SCROLLING;
return;
}
float excess = getExcess();
if (floatsApproxEqual(excess, 0.0f))
mFlingState = FlingStates.STOPPED;
else
mFlingState = FlingStates.WAITING_TO_SNAP;
}
// Advances a fling animation by one step.
public void advanceFling() {
switch (mFlingState) {
case SCROLLING:
scroll();
return;
case WAITING_TO_SNAP:
// We don't do anything until the controller switches us into the snapping state.
return;
case SNAPPING:
snap();
return;
}
}
// Performs one frame of a scroll operation if applicable.
private void scroll() {
// If we aren't overscrolled, just apply friction.
float excess = getExcess();
if (floatsApproxEqual(excess, 0.0f)) {
velocity *= FRICTION;
if (Math.abs(velocity) < 0.1f) {
velocity = 0.0f;
mFlingState = FlingStates.STOPPED;
}
return;
}
// Otherwise, decrease the velocity linearly.
float elasticity = 1.0f - excess / (mViewportLength * SNAP_LIMIT);
if (getOverscroll() == Overscroll.MINUS)
velocity = Math.min((velocity + OVERSCROLL_DECEL_RATE) * elasticity, 0.0f);
else // must be Overscroll.PLUS
velocity = Math.max((velocity - OVERSCROLL_DECEL_RATE) * elasticity, 0.0f);
if (Math.abs(velocity) < 0.3f) {
velocity = 0.0f;
mFlingState = FlingStates.WAITING_TO_SNAP;
}
}
// Starts a snap-into-place operation.
public void startSnap() {
switch (getOverscroll()) {
case MINUS:
mSnapAnim = new EaseOutAnimation(viewportPos, viewportPos + getExcess());
break;
case PLUS:
mSnapAnim = new EaseOutAnimation(viewportPos, viewportPos - getExcess());
break;
default:
throw new RuntimeException("Not overscrolled at startSnap()");
}
mFlingState = FlingStates.SNAPPING;
}
// Performs one frame of a snap-into-place operation.
private void snap() {
mSnapAnim.advance();
viewportPos = mSnapAnim.getPosition();
if (mSnapAnim.getFinished()) {
mSnapAnim = null;
mFlingState = FlingStates.STOPPED;
}
}
// Performs displacement of the viewport position according to the current velocity.
public void displace() { viewportPos += velocity; }
}
private static class EaseOutAnimation {
private float[] mFrames;
private float mPosition;
private float mOrigin;
private float mDest;
private long mTimestamp;
private boolean mFinished;
public EaseOutAnimation(float position, float dest) {
mPosition = mOrigin = position;
mDest = dest;
mFrames = new float[SNAP_TIME];
mTimestamp = System.currentTimeMillis();
mFinished = false;
plot(position, dest, mFrames);
}
public float getPosition() { return mPosition; }
public boolean getFinished() { return mFinished; }
private void advance() {
int frame = (int)(System.currentTimeMillis() - mTimestamp);
if (frame >= SNAP_TIME) {
mPosition = mDest;
mFinished = true;
return;
}
mPosition = mFrames[frame];
}
private static void plot(float from, float to, float[] frames) {
int nextX = 0;
for (int i = 0; i < SUBDIVISION_COUNT; i++) {
float t = (float)i / (float)SUBDIVISION_COUNT;
float xPos = (3.0f*t*t - 2.0f*t*t*t) * (float)frames.length;
if ((int)xPos < nextX)
continue;
int oldX = nextX;
nextX = (int)xPos;
float yPos = 1.74f*t*t - 0.74f*t*t*t;
float framePos = from + (to - from) * yPos;
while (oldX < nextX)
frames[oldX++] = framePos;
if (nextX >= frames.length)
break;
}
// Pad out any remaining frames.
while (nextX < frames.length) {
frames[nextX] = frames[nextX - 1];
nextX++;
}
}
}
/*
* Zooming
*/
@Override
public boolean onScale(ScaleGestureDetector detector) {
mState = PanZoomState.PINCHING;
float newZoom = detector.getCurrentSpan() / mInitialZoomSpan;
IntSize screenSize = mController.getScreenSize();
float x = mInitialZoomFocus.x - (detector.getFocusX() / newZoom);
float y = mInitialZoomFocus.y - (detector.getFocusY() / newZoom);
float width = screenSize.width / newZoom;
float height = screenSize.height / newZoom;
mController.setVisibleRect(x, y, width, height);
mController.notifyLayerClientOfGeometryChange();
populatePositionAndLength();
return true;
}
@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
mState = PanZoomState.PINCHING;
RectF initialZoomRect = mController.getVisibleRect();
float initialZoom = mController.getZoomFactor();
mInitialZoomFocus = new PointF(initialZoomRect.left + (detector.getFocusX() / initialZoom),
initialZoomRect.top + (detector.getFocusY() / initialZoom));
mInitialZoomSpan = detector.getCurrentSpan() / initialZoom;
GeckoApp.mAppContext.hidePluginViews();
return true;
}
@Override
public void onScaleEnd(ScaleGestureDetector detector) {
mState = PanZoomState.PANNING_HOLD;
mLastTimestamp = System.currentTimeMillis();
mX.touchPos = detector.getFocusX();
mY.touchPos = detector.getFocusY();
GeckoApp.mAppContext.showPluginViews();
}
@Override
public void onLongPress(MotionEvent motionEvent) {
JSONObject ret = new JSONObject();
try {
PointF point = new PointF(motionEvent.getX(), motionEvent.getY());
point = mController.convertViewPointToLayerPoint(point);
if (point == null) {
return;
}
ret.put("x", (int)Math.round(point.x));
ret.put("y", (int)Math.round(point.y));
} catch(Exception ex) {
Log.w(LOGTAG, "Error building return: " + ex);
}
GeckoEvent e = new GeckoEvent("Gesture:LongPress", ret.toString());
GeckoAppShell.sendEventToGecko(e);
}
}