Tweak snap settings (75738725) · Commits · e / os / android_frameworks_base

core/java/android/webkit/WebView.java

+56 −45

Original line number	Diff line number	Diff line
		@@ -422,6 +422,9 @@ public class WebView extends AbsoluteLayout
		*/
		private int mLastTouchX;
		private int mLastTouchY;
		private int mStartTouchX;
		private int mStartTouchY;
		private float mAverageAngle;

		/**
		* Time of the last touch event.
		@@ -1189,7 +1192,6 @@ public class WebView extends AbsoluteLayout
		final ViewConfiguration configuration = ViewConfiguration.get(getContext());
		int slop = configuration.getScaledTouchSlop();
		mTouchSlopSquare = slop * slop;
		mMinLockSnapReverseDistance = slop;
		slop = configuration.getScaledDoubleTapSlop();
		mDoubleTapSlopSquare = slop * slop;
		final float density = getContext().getResources().getDisplayMetrics().density;
		@@ -5595,15 +5597,26 @@ public class WebView extends AbsoluteLayout
		}
		}

		// Here are the snap align logic:
		// 1. If it starts nearly horizontally or vertically, snap align;
		// 2. If there is a dramitic direction change, let it go;
		// 3. If there is a same direction back and forth, lock it.

		// adjustable parameters
		private int mMinLockSnapReverseDistance;
		private static final float MAX_SLOPE_FOR_DIAG = 1.5f;
		private static final int MIN_BREAK_SNAP_CROSS_DISTANCE = 80;
		/*
		* Here is the snap align logic:
		* 1. If it starts nearly horizontally or vertically, snap align;
		* 2. If there is a dramitic direction change, let it go;
		*
		* Adjustable parameters. Angle is the radians on a unit circle, limited
		* to quadrant 1. Values range from 0f (horizontal) to PI/2 (vertical)
		*/
		private static final float HSLOPE_TO_START_SNAP = .1f;
		private static final float HSLOPE_TO_BREAK_SNAP = .2f;
		private static final float VSLOPE_TO_START_SNAP = 1.25f;
		private static final float VSLOPE_TO_BREAK_SNAP = .95f;
		/*
		* These values are used to influence the average angle when entering
		* snap mode. If is is the first movement entering snap, we set the average
		* to the appropriate ideal. If the user is entering into snap after the
		* first movement, then we average the average angle with these values.
		*/
		private static final float ANGLE_VERT = 2f;
		private static final float ANGLE_HORIZ = 0f;

		private boolean hitFocusedPlugin(int contentX, int contentY) {
		if (DebugFlags.WEB_VIEW) {
		@@ -5709,6 +5722,12 @@ public class WebView extends AbsoluteLayout
		return true;
		}

		private float calculateDragAngle(int dx, int dy) {
		dx = Math.abs(dx);
		dy = Math.abs(dy);
		return (float) Math.atan2(dy, dx);
		}

		/*
		* Common code for single touch and multi-touch.
		* (x, y) denotes current focus point, which is the touch point for single touch
		@@ -5954,16 +5973,17 @@ public class WebView extends AbsoluteLayout
		// if mZoomManager.supportsPanDuringZoom() is true.
		final ScaleGestureDetector detector =
		mZoomManager.getMultiTouchGestureDetector();
		mAverageAngle = calculateDragAngle(deltaX, deltaY);
		if (detector == null \|\| !detector.isInProgress()) {
		// if it starts nearly horizontal or vertical, enforce it
		int ax = Math.abs(deltaX);
		int ay = Math.abs(deltaY);
		if (ax > MAX_SLOPE_FOR_DIAG * ay) {
		if (mAverageAngle < HSLOPE_TO_START_SNAP) {
		mSnapScrollMode = SNAP_X;
		mSnapPositive = deltaX > 0;
		} else if (ay > MAX_SLOPE_FOR_DIAG * ax) {
		mAverageAngle = ANGLE_HORIZ;
		} else if (mAverageAngle > VSLOPE_TO_START_SNAP) {
		mSnapScrollMode = SNAP_Y;
		mSnapPositive = deltaY > 0;
		mAverageAngle = ANGLE_VERT;
		}
		}

		@@ -5983,35 +6003,30 @@ public class WebView extends AbsoluteLayout
		if (deltaX == 0 && deltaY == 0) {
		keepScrollBarsVisible = done = true;
		} else {
		if (mSnapScrollMode == SNAP_X \|\| mSnapScrollMode == SNAP_Y) {
		int ax = Math.abs(deltaX);
		int ay = Math.abs(deltaY);
		if (mSnapScrollMode == SNAP_X) {
		mAverageAngle = (mAverageAngle +
		calculateDragAngle(deltaX, deltaY)) / 2;
		if (mSnapScrollMode != SNAP_NONE) {
		if (mSnapScrollMode == SNAP_Y) {
		// radical change means getting out of snap mode
		if (ay > MAX_SLOPE_FOR_DIAG * ax
		&& ay > MIN_BREAK_SNAP_CROSS_DISTANCE) {
		if (mAverageAngle < VSLOPE_TO_BREAK_SNAP) {
		mSnapScrollMode = SNAP_NONE;
		}
		// reverse direction means lock in the snap mode
		if (ax > MAX_SLOPE_FOR_DIAG * ay &&
		(mSnapPositive
		? deltaX < -mMinLockSnapReverseDistance
		: deltaX > mMinLockSnapReverseDistance)) {
		mSnapScrollMode \|= SNAP_LOCK;
		}
		} else {
		if (mSnapScrollMode == SNAP_X) {
		// radical change means getting out of snap mode
		if (ax > MAX_SLOPE_FOR_DIAG * ay
		&& ax > MIN_BREAK_SNAP_CROSS_DISTANCE) {
		if (mAverageAngle > HSLOPE_TO_BREAK_SNAP) {
		mSnapScrollMode = SNAP_NONE;
		}
		// reverse direction means lock in the snap mode
		if (ay > MAX_SLOPE_FOR_DIAG * ax &&
		(mSnapPositive
		? deltaY < -mMinLockSnapReverseDistance
		: deltaY > mMinLockSnapReverseDistance)) {
		mSnapScrollMode \|= SNAP_LOCK;
		}
		} else {
		if (mAverageAngle < HSLOPE_TO_START_SNAP) {
		mSnapScrollMode = SNAP_X;
		mSnapPositive = deltaX > 0;
		mAverageAngle = (mAverageAngle + ANGLE_HORIZ) / 2;
		} else if (mAverageAngle > VSLOPE_TO_START_SNAP) {
		mSnapScrollMode = SNAP_Y;
		mSnapPositive = deltaY > 0;
		mAverageAngle = (mAverageAngle + ANGLE_VERT) / 2;
		}
		}
		if (mSnapScrollMode != SNAP_NONE) {
		@@ -6021,13 +6036,9 @@ public class WebView extends AbsoluteLayout
		deltaX = 0;
		}
		}
		if ((deltaX \| deltaY) != 0) {
		if (deltaX != 0) {
		mLastTouchX = x;
		}
		if (deltaY != 0) {
		mLastTouchY = y;
		}
		if ((deltaX \| deltaY) != 0) {
		mHeldMotionless = MOTIONLESS_FALSE;
		}
		mLastTouchTime = eventTime;
		@@ -6337,8 +6348,8 @@ public class WebView extends AbsoluteLayout

		private void startTouch(float x, float y, long eventTime) {
		// Remember where the motion event started
		mLastTouchX = Math.round(x);
		mLastTouchY = Math.round(y);
		mStartTouchX = mLastTouchX = Math.round(x);
		mStartTouchY = mLastTouchY = Math.round(y);
		mLastTouchTime = eventTime;
		mVelocityTracker = VelocityTracker.obtain();
		mSnapScrollMode = SNAP_NONE;