/*
* 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 SimpleScaleGestureDetector.SimpleScaleGestureListener, GeckoEventListener {
private static final String LOGTAG = "GeckoPanZoomController";
private static String MESSAGE_ZOOM_RECT = "Browser:ZoomToRect";
private static String MESSAGE_ZOOM_PAGE = "Browser:ZoomToPageWidth";
// Animation stops if the velocity is below this value when overscrolled or panning.
private static final float STOPPED_THRESHOLD = 4.0f;
// Animation stops is the velocity is below this threshold when flinging.
private static final float FLING_STOPPED_THRESHOLD = 0.1f;
// 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). In units of density-independent pixels.
public static final float PAN_THRESHOLD = 1 / 16f * GeckoAppShell.getDpi();
// Angle from axis within which we stay axis-locked
private static final double AXIS_LOCK_ANGLE = Math.PI / 6.0; // 30 degrees
// The maximum amount we allow you to zoom into a page
private static final float MAX_ZOOM = 4.0f;
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_LOCKED, /* touch-start followed by move (i.e. panning with axis lock) */
PANNING, /* panning without axis lock */
PANNING_HOLD, /* in panning, but not moving.
* similar to TOUCHING but after starting a pan */
PANNING_HOLD_LOCKED, /* like PANNING_HOLD, but axis lock still in effect */
PINCHING, /* nth touch-start, where n > 1. this mode allows pan and zoom */
ANIMATED_ZOOM, /* animated zoom to a new rect */
BOUNCE, /* in a bounce animation */
WAITING_LISTENERS, /* a state halfway between NOTHING and TOUCHING - the user has
put a finger down, but we don't yet know if a touch listener has
prevented the default actions yet. we still need to abort animations. */
}
private final PanZoomTarget mTarget;
private final SubdocumentScrollHelper mSubscroller;
private final Axis mX;
private final Axis mY;
private final EventDispatcher mEventDispatcher;
private Thread mMainThread;
/* The timer that handles flings or bounces. */
private Timer mAnimationTimer;
/* The runnable being scheduled by the animation timer. */
private AnimationRunnable mAnimationRunnable;
/* The zoom focus at the first zoom event (in page coordinates). */
private PointF mLastZoomFocus;
/* The time the last motion event took place. */
private long mLastEventTime;
/* Current state the pan/zoom UI is in. */
private PanZoomState mState;
public PanZoomController(PanZoomTarget target, EventDispatcher eventDispatcher) {
mTarget = target;
mSubscroller = new SubdocumentScrollHelper(this, eventDispatcher);
mX = new AxisX(mSubscroller);
mY = new AxisY(mSubscroller);
mMainThread = GeckoApp.mAppContext.getMainLooper().getThread();
checkMainThread();
setState(PanZoomState.NOTHING);
mEventDispatcher = eventDispatcher;
registerEventListener(MESSAGE_ZOOM_RECT);
registerEventListener(MESSAGE_ZOOM_PAGE);
Axis.initPrefs();
}
public void destroy() {
unregisterEventListener(MESSAGE_ZOOM_RECT);
unregisterEventListener(MESSAGE_ZOOM_PAGE);
mSubscroller.destroy();
}
private static final float easeOut(float t) {
// ease-out approx.
// -(t-1)^2+1
t = t - 1;
return -t * t + 1;
}
private void registerEventListener(String event) {
mEventDispatcher.registerEventListener(event, this);
}
private void unregisterEventListener(String event) {
mEventDispatcher.unregisterEventListener(event, this);
}
private void setState(PanZoomState state) {
mState = state;
}
private ImmutableViewportMetrics getMetrics() {
return mTarget.getViewportMetrics();
}
// for debugging bug 713011; it can be taken out once that is resolved.
private void checkMainThread() {
if (mMainThread != Thread.currentThread()) {
// log with full stack trace
Log.e(LOGTAG, "Uh-oh, we're running on the wrong thread!", new Exception());
}
}
public void handleMessage(String event, JSONObject message) {
try {
if (MESSAGE_ZOOM_RECT.equals(event)) {
float x = (float) message.getDouble("x");
float y = (float) message.getDouble("y");
final RectF zoomRect =
new RectF(x, y, x + (float) message.getDouble("w"), y + (float) message.getDouble("h"));
mTarget.post(
new Runnable() {
public void run() {
animatedZoomTo(zoomRect);
}
});
} else if (MESSAGE_ZOOM_PAGE.equals(event)) {
ImmutableViewportMetrics metrics = getMetrics();
RectF cssPageRect = metrics.getCssPageRect();
RectF viewableRect = metrics.getCssViewport();
float y = viewableRect.top;
// attempt to keep zoom keep focused on the center of the viewport
float newHeight = viewableRect.height() * cssPageRect.width() / viewableRect.width();
float dh = viewableRect.height() - newHeight; // increase in the height
final RectF r = new RectF(0.0f, y + dh / 2, cssPageRect.width(), y + dh / 2 + newHeight);
mTarget.post(
new Runnable() {
public void run() {
animatedZoomTo(r);
}
});
}
} catch (Exception e) {
Log.e(LOGTAG, "Exception handling message \"" + event + "\":", e);
}
}
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction() & MotionEvent.ACTION_MASK) {
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;
}
}
/** This function must be called from the UI thread. */
public void abortAnimation() {
checkMainThread();
// this happens when gecko changes the viewport on us or if the device is rotated.
// if that's the case, abort any animation in progress and re-zoom so that the page
// snaps to edges. for other cases (where the user's finger(s) are down) don't do
// anything special.
switch (mState) {
case FLING:
mX.stopFling();
mY.stopFling();
// fall through
case BOUNCE:
case ANIMATED_ZOOM:
// the zoom that's in progress likely makes no sense any more (such as if
// the screen orientation changed) so abort it
setState(PanZoomState.NOTHING);
// fall through
case NOTHING:
// Don't do animations here; they're distracting and can cause flashes on page
// transitions.
synchronized (mTarget.getLock()) {
mTarget.setViewportMetrics(getValidViewportMetrics());
}
break;
}
}
/** This function must be called on the UI thread. */
public void startingNewEventBlock(MotionEvent event, boolean waitingForTouchListeners) {
checkMainThread();
mSubscroller.cancel();
if (waitingForTouchListeners
&& (event.getAction() & MotionEvent.ACTION_MASK) == MotionEvent.ACTION_DOWN) {
// this is the first touch point going down, so we enter the pending state
// seting the state will kill any animations in progress, possibly leaving
// the page in overscroll
setState(PanZoomState.WAITING_LISTENERS);
}
}
/** This function must be called on the UI thread. */
public void preventedTouchFinished() {
checkMainThread();
if (mState == PanZoomState.WAITING_LISTENERS) {
// if we enter here, we just finished a block of events whose default actions
// were prevented by touch listeners. Now there are no touch points left, so
// we need to reset our state and re-bounce because we might be in overscroll
bounce();
}
}
/** This must be called on the UI thread. */
public void pageRectUpdated() {
if (mState == PanZoomState.NOTHING) {
synchronized (mTarget.getLock()) {
ImmutableViewportMetrics validated = getValidViewportMetrics();
if (!getMetrics().fuzzyEquals(validated)) {
// page size changed such that we are now in overscroll. snap to the
// the nearest valid viewport
mTarget.setViewportMetrics(validated);
}
}
}
}
/*
* Panning/scrolling
*/
private boolean onTouchStart(MotionEvent event) {
// user is taking control of movement, so stop
// any auto-movement we have going
stopAnimationTimer();
switch (mState) {
case ANIMATED_ZOOM:
// We just interrupted a double-tap animation, so force a redraw in
// case this touchstart is just a tap that doesn't end up triggering
// a redraw
mTarget.setForceRedraw();
// fall through
case FLING:
case BOUNCE:
case NOTHING:
case WAITING_LISTENERS:
startTouch(event.getX(0), event.getY(0), event.getEventTime());
return false;
case TOUCHING:
case PANNING:
case PANNING_LOCKED:
case PANNING_HOLD:
case PANNING_HOLD_LOCKED:
case PINCHING:
Log.e(LOGTAG, "Received impossible touch down while in " + mState);
return false;
}
Log.e(LOGTAG, "Unhandled case " + mState + " in onTouchStart");
return false;
}
private boolean onTouchMove(MotionEvent event) {
switch (mState) {
case FLING:
case BOUNCE:
case WAITING_LISTENERS:
// should never happen
Log.e(LOGTAG, "Received impossible touch move while in " + mState);
// fall through
case ANIMATED_ZOOM:
case NOTHING:
// may happen if user double-taps and drags without lifting after the
// second tap. ignore the move if this happens.
return false;
case TOUCHING:
if (panDistance(event) < PAN_THRESHOLD) {
return false;
}
cancelTouch();
startPanning(event.getX(0), event.getY(0), event.getEventTime());
track(event);
return true;
case PANNING_HOLD_LOCKED:
setState(PanZoomState.PANNING_LOCKED);
// fall through
case PANNING_LOCKED:
track(event);
return true;
case PANNING_HOLD:
setState(PanZoomState.PANNING);
// fall through
case PANNING:
track(event);
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 FLING:
case BOUNCE:
case WAITING_LISTENERS:
// should never happen
Log.e(LOGTAG, "Received impossible touch end while in " + mState);
// fall through
case ANIMATED_ZOOM:
case NOTHING:
// may happen if user double-taps and drags without lifting after the
// second tap. ignore if this happens.
return false;
case TOUCHING:
// the switch into TOUCHING might have happened while the page was
// snapping back after overscroll. we need to finish the snap if that
// was the case
bounce();
return false;
case PANNING:
case PANNING_LOCKED:
case PANNING_HOLD:
case PANNING_HOLD_LOCKED:
setState(PanZoomState.FLING);
fling();
return true;
case PINCHING:
setState(PanZoomState.NOTHING);
return true;
}
Log.e(LOGTAG, "Unhandled case " + mState + " in onTouchEnd");
return false;
}
private boolean onTouchCancel(MotionEvent event) {
cancelTouch();
if (mState == PanZoomState.WAITING_LISTENERS) {
// we might get a cancel event from the TouchEventHandler while in the
// WAITING_LISTENERS state if the touch listeners prevent-default the
// block of events. at this point being in WAITING_LISTENERS is equivalent
// to being in NOTHING with the exception of possibly being in overscroll.
// so here we don't want to do anything right now; the overscroll will be
// corrected in preventedTouchFinished().
return false;
}
// ensure we snap back if we're overscrolled
bounce();
return false;
}
private void startTouch(float x, float y, long time) {
mX.startTouch(x);
mY.startTouch(y);
setState(PanZoomState.TOUCHING);
mLastEventTime = time;
}
private void startPanning(float x, float y, long time) {
float dx = mX.panDistance(x);
float dy = mY.panDistance(y);
double angle = Math.atan2(dy, dx); // range [-pi, pi]
angle = Math.abs(angle); // range [0, pi]
// When the touch move breaks through the pan threshold, reposition the touch down origin
// so the page won't jump when we start panning.
mX.startTouch(x);
mY.startTouch(y);
mLastEventTime = time;
if (!mX.scrollable() || !mY.scrollable()) {
setState(PanZoomState.PANNING);
} else if (angle < AXIS_LOCK_ANGLE || angle > (Math.PI - AXIS_LOCK_ANGLE)) {
mY.setScrollingDisabled(true);
setState(PanZoomState.PANNING_LOCKED);
} else if (Math.abs(angle - (Math.PI / 2)) < AXIS_LOCK_ANGLE) {
mX.setScrollingDisabled(true);
setState(PanZoomState.PANNING_LOCKED);
} else {
setState(PanZoomState.PANNING);
}
}
private float panDistance(MotionEvent move) {
float dx = mX.panDistance(move.getX(0));
float dy = mY.panDistance(move.getY(0));
return FloatMath.sqrt(dx * dx + dy * dy);
}
private void track(float x, float y, long time) {
float timeDelta = (float) (time - mLastEventTime);
if (FloatUtils.fuzzyEquals(timeDelta, 0)) {
// probably a duplicate event, ignore it. using a zero timeDelta will mess
// up our velocity
return;
}
mLastEventTime = time;
mX.updateWithTouchAt(x, timeDelta);
mY.updateWithTouchAt(y, timeDelta);
}
private void track(MotionEvent event) {
mX.saveTouchPos();
mY.saveTouchPos();
for (int i = 0; i < event.getHistorySize(); i++) {
track(
event.getHistoricalX(0, i), event.getHistoricalY(0, i), event.getHistoricalEventTime(i));
}
track(event.getX(0), event.getY(0), event.getEventTime());
if (stopped()) {
if (mState == PanZoomState.PANNING) {
setState(PanZoomState.PANNING_HOLD);
} else if (mState == PanZoomState.PANNING_LOCKED) {
setState(PanZoomState.PANNING_HOLD_LOCKED);
} else {
// should never happen, but handle anyway for robustness
Log.e(LOGTAG, "Impossible case " + mState + " when stopped in track");
setState(PanZoomState.PANNING_HOLD_LOCKED);
}
}
mX.startPan();
mY.startPan();
updatePosition();
}
private void scrollBy(float dx, float dy) {
ImmutableViewportMetrics scrolled = getMetrics().offsetViewportBy(dx, dy);
mTarget.setViewportMetrics(scrolled);
}
private void fling() {
updatePosition();
stopAnimationTimer();
boolean stopped = stopped();
mX.startFling(stopped);
mY.startFling(stopped);
startAnimationTimer(new FlingRunnable());
}
/* Performs a bounce-back animation to the given viewport metrics. */
private void bounce(ImmutableViewportMetrics metrics) {
stopAnimationTimer();
ImmutableViewportMetrics bounceStartMetrics = getMetrics();
if (bounceStartMetrics.fuzzyEquals(metrics)) {
setState(PanZoomState.NOTHING);
return;
}
// At this point we have already set mState to BOUNCE or ANIMATED_ZOOM, so
// getRedrawHint() is returning false. This means we can safely call
// setAnimationTarget to set the new final display port and not have it get
// clobbered by display ports from intermediate animation frames.
mTarget.setAnimationTarget(metrics);
startAnimationTimer(new BounceRunnable(bounceStartMetrics, metrics));
}
/* Performs a bounce-back animation to the nearest valid viewport metrics. */
private void bounce() {
setState(PanZoomState.BOUNCE);
bounce(getValidViewportMetrics());
}
/* Starts the fling or bounce animation. */
private void startAnimationTimer(final AnimationRunnable runnable) {
if (mAnimationTimer != null) {
Log.e(LOGTAG, "Attempted to start a new fling without canceling the old one!");
stopAnimationTimer();
}
mAnimationTimer = new Timer("Animation Timer");
mAnimationRunnable = runnable;
mAnimationTimer.scheduleAtFixedRate(
new TimerTask() {
@Override
public void run() {
mTarget.post(runnable);
}
},
0,
(int) Axis.MS_PER_FRAME);
}
/* Stops the fling or bounce animation. */
private void stopAnimationTimer() {
if (mAnimationTimer != null) {
mAnimationTimer.cancel();
mAnimationTimer = null;
}
if (mAnimationRunnable != null) {
mAnimationRunnable.terminate();
mAnimationRunnable = null;
}
}
private float getVelocity() {
float xvel = mX.getRealVelocity();
float yvel = mY.getRealVelocity();
return FloatMath.sqrt(xvel * xvel + yvel * yvel);
}
public PointF getVelocityVector() {
return new PointF(mX.getRealVelocity(), mY.getRealVelocity());
}
private boolean stopped() {
return getVelocity() < STOPPED_THRESHOLD;
}
PointF resetDisplacement() {
return new PointF(mX.resetDisplacement(), mY.resetDisplacement());
}
private void updatePosition() {
mX.displace();
mY.displace();
PointF displacement = resetDisplacement();
if (FloatUtils.fuzzyEquals(displacement.x, 0.0f)
&& FloatUtils.fuzzyEquals(displacement.y, 0.0f)) {
return;
}
if (!mSubscroller.scrollBy(displacement)) {
synchronized (mTarget.getLock()) {
scrollBy(displacement.x, displacement.y);
}
}
}
private abstract class AnimationRunnable implements Runnable {
private boolean mAnimationTerminated;
/* This should always run on the UI thread */
public final void run() {
/*
* Since the animation timer queues this runnable on the UI thread, it
* is possible that even when the animation timer is cancelled, there
* are multiple instances of this queued, so we need to have another
* mechanism to abort. This is done by using the mAnimationTerminated flag.
*/
if (mAnimationTerminated) {
return;
}
animateFrame();
}
protected abstract void animateFrame();
/* This should always run on the UI thread */
protected final void terminate() {
mAnimationTerminated = true;
}
}
/* The callback that performs the bounce animation. */
private class BounceRunnable extends AnimationRunnable {
/* The current frame of the bounce-back animation */
private int mBounceFrame;
/*
* The viewport metrics that represent the start and end of the bounce-back animation,
* respectively.
*/
private ImmutableViewportMetrics mBounceStartMetrics;
private ImmutableViewportMetrics mBounceEndMetrics;
BounceRunnable(ImmutableViewportMetrics startMetrics, ImmutableViewportMetrics endMetrics) {
mBounceStartMetrics = startMetrics;
mBounceEndMetrics = endMetrics;
}
protected void animateFrame() {
/*
* The pan/zoom controller might have signaled to us that it wants to abort the
* animation by setting the state to PanZoomState.NOTHING. Handle this case and bail
* out.
*/
if (!(mState == PanZoomState.BOUNCE || mState == PanZoomState.ANIMATED_ZOOM)) {
finishAnimation();
return;
}
/* Perform the next frame of the bounce-back animation. */
if (mBounceFrame < (int) (256f / Axis.MS_PER_FRAME)) {
advanceBounce();
return;
}
/* Finally, if there's nothing else to do, complete the animation and go to sleep. */
finishBounce();
finishAnimation();
setState(PanZoomState.NOTHING);
}
/* Performs one frame of a bounce animation. */
private void advanceBounce() {
synchronized (mTarget.getLock()) {
float t = easeOut(mBounceFrame * Axis.MS_PER_FRAME / 256f);
ImmutableViewportMetrics newMetrics = mBounceStartMetrics.interpolate(mBounceEndMetrics, t);
mTarget.setViewportMetrics(newMetrics);
mBounceFrame++;
}
}
/* Concludes a bounce animation and snaps the viewport into place. */
private void finishBounce() {
synchronized (mTarget.getLock()) {
mTarget.setViewportMetrics(mBounceEndMetrics);
mBounceFrame = -1;
}
}
}
// The callback that performs the fling animation.
private class FlingRunnable extends AnimationRunnable {
protected void animateFrame() {
/*
* The pan/zoom controller might have signaled to us that it wants to abort the
* animation by setting the state to PanZoomState.NOTHING. Handle this case and bail
* out.
*/
if (mState != PanZoomState.FLING) {
finishAnimation();
return;
}
/* Advance flings, if necessary. */
boolean flingingX = mX.advanceFling();
boolean flingingY = mY.advanceFling();
boolean overscrolled = (mX.overscrolled() || mY.overscrolled());
/* If we're still flinging in any direction, update the origin. */
if (flingingX || flingingY) {
updatePosition();
/*
* Check to see if we're still flinging with an appreciable velocity. The threshold is
* higher in the case of overscroll, so we bounce back eagerly when overscrolling but
* coast smoothly to a stop when not. In other words, require a greater velocity to
* maintain the fling once we enter overscroll.
*/
float threshold =
(overscrolled && !mSubscroller.scrolling()
? STOPPED_THRESHOLD
: FLING_STOPPED_THRESHOLD);
if (getVelocity() >= threshold) {
// we're still flinging
return;
}
mX.stopFling();
mY.stopFling();
}
/* Perform a bounce-back animation if overscrolled. */
if (overscrolled) {
bounce();
} else {
finishAnimation();
setState(PanZoomState.NOTHING);
}
}
}
private void finishAnimation() {
checkMainThread();
stopAnimationTimer();
// Force a viewport synchronisation
mTarget.setForceRedraw();
}
/* Returns the nearest viewport metrics with no overscroll visible. */
private ImmutableViewportMetrics getValidViewportMetrics() {
return getValidViewportMetrics(getMetrics());
}
private ImmutableViewportMetrics getValidViewportMetrics(
ImmutableViewportMetrics viewportMetrics) {
/* First, we adjust the zoom factor so that we can make no overscrolled area visible. */
float zoomFactor = viewportMetrics.zoomFactor;
RectF pageRect = viewportMetrics.getPageRect();
RectF viewport = viewportMetrics.getViewport();
float focusX = viewport.width() / 2.0f;
float focusY = viewport.height() / 2.0f;
float minZoomFactor = 0.0f;
float maxZoomFactor = MAX_ZOOM;
ZoomConstraints constraints = mTarget.getZoomConstraints();
if (constraints.getMinZoom() > 0) minZoomFactor = constraints.getMinZoom();
if (constraints.getMaxZoom() > 0) maxZoomFactor = constraints.getMaxZoom();
if (!constraints.getAllowZoom()) {
// If allowZoom is false, clamp to the default zoom level.
maxZoomFactor = minZoomFactor = constraints.getDefaultZoom();
}
// Ensure minZoomFactor keeps the page at least as big as the viewport.
if (pageRect.width() > 0) {
float scaleFactor = viewport.width() / pageRect.width();
minZoomFactor = Math.max(minZoomFactor, zoomFactor * scaleFactor);
if (viewport.width() > pageRect.width()) focusX = 0.0f;
}
if (pageRect.height() > 0) {
float scaleFactor = viewport.height() / pageRect.height();
minZoomFactor = Math.max(minZoomFactor, zoomFactor * scaleFactor);
if (viewport.height() > pageRect.height()) focusY = 0.0f;
}
maxZoomFactor = Math.max(maxZoomFactor, minZoomFactor);
if (zoomFactor < minZoomFactor) {
// if one (or both) of the page dimensions is smaller than the viewport,
// zoom using the top/left as the focus on that axis. this prevents the
// scenario where, if both dimensions are smaller than the viewport, but
// by different scale factors, we end up scrolled to the end on one axis
// after applying the scale
PointF center = new PointF(focusX, focusY);
viewportMetrics = viewportMetrics.scaleTo(minZoomFactor, center);
} else if (zoomFactor > maxZoomFactor) {
PointF center = new PointF(viewport.width() / 2.0f, viewport.height() / 2.0f);
viewportMetrics = viewportMetrics.scaleTo(maxZoomFactor, center);
}
/* Now we pan to the right origin. */
viewportMetrics = viewportMetrics.clamp();
return viewportMetrics;
}
private class AxisX extends Axis {
AxisX(SubdocumentScrollHelper subscroller) {
super(subscroller);
}
@Override
public float getOrigin() {
return getMetrics().viewportRectLeft;
}
@Override
protected float getViewportLength() {
return getMetrics().getWidth();
}
@Override
protected float getPageStart() {
return getMetrics().pageRectLeft;
}
@Override
protected float getPageLength() {
return getMetrics().getPageWidth();
}
}
private class AxisY extends Axis {
AxisY(SubdocumentScrollHelper subscroller) {
super(subscroller);
}
@Override
public float getOrigin() {
return getMetrics().viewportRectTop;
}
@Override
protected float getViewportLength() {
return getMetrics().getHeight();
}
@Override
protected float getPageStart() {
return getMetrics().pageRectTop;
}
@Override
protected float getPageLength() {
return getMetrics().getPageHeight();
}
}
/*
* Zooming
*/
@Override
public boolean onScaleBegin(SimpleScaleGestureDetector detector) {
if (mState == PanZoomState.ANIMATED_ZOOM) return false;
if (!mTarget.getZoomConstraints().getAllowZoom()) return false;
setState(PanZoomState.PINCHING);
mLastZoomFocus = new PointF(detector.getFocusX(), detector.getFocusY());
cancelTouch();
GeckoAppShell.sendEventToGecko(
GeckoEvent.createNativeGestureEvent(
GeckoEvent.ACTION_MAGNIFY_START, mLastZoomFocus, getMetrics().zoomFactor));
return true;
}
@Override
public boolean onScale(SimpleScaleGestureDetector detector) {
if (GeckoApp.mAppContext == null || GeckoApp.mAppContext.mDOMFullScreen) return false;
if (mState != PanZoomState.PINCHING) return false;
float prevSpan = detector.getPreviousSpan();
if (FloatUtils.fuzzyEquals(prevSpan, 0.0f)) {
// let's eat this one to avoid setting the new zoom to infinity (bug 711453)
return true;
}
float spanRatio = detector.getCurrentSpan() / prevSpan;
/*
* Apply edge resistance if we're zoomed out smaller than the page size by scaling the zoom
* factor toward 1.0.
*/
float resistance = Math.min(mX.getEdgeResistance(true), mY.getEdgeResistance(true));
if (spanRatio > 1.0f) spanRatio = 1.0f + (spanRatio - 1.0f) * resistance;
else spanRatio = 1.0f - (1.0f - spanRatio) * resistance;
synchronized (mTarget.getLock()) {
float newZoomFactor = getMetrics().zoomFactor * spanRatio;
float minZoomFactor = 0.0f;
float maxZoomFactor = MAX_ZOOM;
ZoomConstraints constraints = mTarget.getZoomConstraints();
if (constraints.getMinZoom() > 0) minZoomFactor = constraints.getMinZoom();
if (constraints.getMaxZoom() > 0) maxZoomFactor = constraints.getMaxZoom();
if (newZoomFactor < minZoomFactor) {
// apply resistance when zooming past minZoomFactor,
// such that it asymptotically reaches minZoomFactor / 2.0
// but never exceeds that
final float rate = 0.5f; // controls how quickly we approach the limit
float excessZoom = minZoomFactor - newZoomFactor;
excessZoom = 1.0f - (float) Math.exp(-excessZoom * rate);
newZoomFactor = minZoomFactor * (1.0f - excessZoom / 2.0f);
}
if (newZoomFactor > maxZoomFactor) {
// apply resistance when zooming past maxZoomFactor,
// such that it asymptotically reaches maxZoomFactor + 1.0
// but never exceeds that
float excessZoom = newZoomFactor - maxZoomFactor;
excessZoom = 1.0f - (float) Math.exp(-excessZoom);
newZoomFactor = maxZoomFactor + excessZoom;
}
scrollBy(mLastZoomFocus.x - detector.getFocusX(), mLastZoomFocus.y - detector.getFocusY());
PointF focus = new PointF(detector.getFocusX(), detector.getFocusY());
scaleWithFocus(newZoomFactor, focus);
}
mLastZoomFocus.set(detector.getFocusX(), detector.getFocusY());
GeckoEvent event =
GeckoEvent.createNativeGestureEvent(
GeckoEvent.ACTION_MAGNIFY, mLastZoomFocus, getMetrics().zoomFactor);
GeckoAppShell.sendEventToGecko(event);
return true;
}
@Override
public void onScaleEnd(SimpleScaleGestureDetector detector) {
if (mState == PanZoomState.ANIMATED_ZOOM) return;
// switch back to the touching state
startTouch(detector.getFocusX(), detector.getFocusY(), detector.getEventTime());
// Force a viewport synchronisation
mTarget.setForceRedraw();
PointF point = new PointF(detector.getFocusX(), detector.getFocusY());
GeckoEvent event =
GeckoEvent.createNativeGestureEvent(
GeckoEvent.ACTION_MAGNIFY_END, point, getMetrics().zoomFactor);
if (event == null) {
return;
}
GeckoAppShell.sendEventToGecko(event);
}
/**
* Scales the viewport, keeping the given focus point in the same place before and after the scale
* operation. You must hold the monitor while calling this.
*/
private void scaleWithFocus(float zoomFactor, PointF focus) {
ImmutableViewportMetrics viewportMetrics = getMetrics();
viewportMetrics = viewportMetrics.scaleTo(zoomFactor, focus);
mTarget.setViewportMetrics(viewportMetrics);
}
public boolean getRedrawHint() {
switch (mState) {
case PINCHING:
case ANIMATED_ZOOM:
case BOUNCE:
// don't redraw during these because the zoom is (or might be, in the case
// of BOUNCE) be changing rapidly and gecko will have to redraw the entire
// display port area. we trigger a force-redraw upon exiting these states.
return false;
default:
// allow redrawing in other states
return true;
}
}
private void sendPointToGecko(String event, MotionEvent motionEvent) {
String json;
try {
PointF point = new PointF(motionEvent.getX(), motionEvent.getY());
point = mTarget.convertViewPointToLayerPoint(point);
if (point == null) {
return;
}
json = PointUtils.toJSON(point).toString();
} catch (Exception e) {
Log.e(LOGTAG, "Unable to convert point to JSON for " + event, e);
return;
}
GeckoAppShell.sendEventToGecko(GeckoEvent.createBroadcastEvent(event, json));
}
@Override
public void onLongPress(MotionEvent motionEvent) {
sendPointToGecko("Gesture:LongPress", motionEvent);
}
@Override
public boolean onSingleTapUp(MotionEvent motionEvent) {
// When zooming is enabled, wait to see if there's a double-tap.
if (!mTarget.getZoomConstraints().getAllowZoom()) {
sendPointToGecko("Gesture:SingleTap", motionEvent);
}
// return false because we still want to get the ACTION_UP event that triggers this
return false;
}
@Override
public boolean onSingleTapConfirmed(MotionEvent motionEvent) {
// When zooming is disabled, we handle this in onSingleTapUp.
if (mTarget.getZoomConstraints().getAllowZoom()) {
sendPointToGecko("Gesture:SingleTap", motionEvent);
}
return true;
}
@Override
public boolean onDoubleTap(MotionEvent motionEvent) {
if (mTarget.getZoomConstraints().getAllowZoom()) {
sendPointToGecko("Gesture:DoubleTap", motionEvent);
}
return true;
}
private void cancelTouch() {
GeckoEvent e = GeckoEvent.createBroadcastEvent("Gesture:CancelTouch", "");
GeckoAppShell.sendEventToGecko(e);
}
/**
* Zoom to a specified rect IN CSS PIXELS.
*
* <p>While we usually use device pixels, @zoomToRect must be specified in CSS pixels.
*/
private boolean animatedZoomTo(RectF zoomToRect) {
setState(PanZoomState.ANIMATED_ZOOM);
final float startZoom = getMetrics().zoomFactor;
RectF viewport = getMetrics().getViewport();
// 1. adjust the aspect ratio of zoomToRect to match that of the current viewport,
// enlarging as necessary (if it gets too big, it will get shrunk in the next step).
// while enlarging make sure we enlarge equally on both sides to keep the target rect
// centered.
float targetRatio = viewport.width() / viewport.height();
float rectRatio = zoomToRect.width() / zoomToRect.height();
if (FloatUtils.fuzzyEquals(targetRatio, rectRatio)) {
// all good, do nothing
} else if (targetRatio < rectRatio) {
// need to increase zoomToRect height
float newHeight = zoomToRect.width() / targetRatio;
zoomToRect.top -= (newHeight - zoomToRect.height()) / 2;
zoomToRect.bottom = zoomToRect.top + newHeight;
} else { // targetRatio > rectRatio) {
// need to increase zoomToRect width
float newWidth = targetRatio * zoomToRect.height();
zoomToRect.left -= (newWidth - zoomToRect.width()) / 2;
zoomToRect.right = zoomToRect.left + newWidth;
}
float finalZoom = viewport.width() / zoomToRect.width();
ImmutableViewportMetrics finalMetrics = getMetrics();
finalMetrics =
finalMetrics.setViewportOrigin(
zoomToRect.left * finalMetrics.zoomFactor, zoomToRect.top * finalMetrics.zoomFactor);
finalMetrics = finalMetrics.scaleTo(finalZoom, new PointF(0.0f, 0.0f));
// 2. now run getValidViewportMetrics on it, so that the target viewport is
// clamped down to prevent overscroll, over-zoom, and other bad conditions.
finalMetrics = getValidViewportMetrics(finalMetrics);
bounce(finalMetrics);
return true;
}
/** This function must be called from the UI thread. */
public void abortPanning() {
checkMainThread();
bounce();
}
public void setOverScrollMode(int overscrollMode) {
mX.setOverScrollMode(overscrollMode);
mY.setOverScrollMode(overscrollMode);
}
public int getOverScrollMode() {
return mX.getOverScrollMode();
}
}
