Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 61324dbf authored by George Mount's avatar George Mount
Browse files

Use spring animation for stretch overscroll 

Bug: 171228096

Use the spring animation from the prototype in
EdgeEffect.

Test: manual testing for fling and recede

Change-Id: I7eec03a98f5d26153512ba402d6bb5bc5dc70ffb
parent af1e8b4e

core/java/android/widget/EdgeEffect.java

+102 −37
Original line number Diff line number Diff line
@@ -76,6 +76,28 @@ public class EdgeEffect { 
     */

    public static final int TYPE_STRETCH = 1;



    /**

     * The velocity threshold before the spring animation is considered settled.

     * The idea here is that velocity should be less than 1 pixel per frame (~16ms).

     */

    private static final double VELOCITY_THRESHOLD = 1.0 / 0.016;



    /**

     * The value threshold before the spring animation is considered close enough to

     * the destination to be settled. This should be around 1 pixel.

     */

    private static final double VALUE_THRESHOLD = 1;



    /**

     * The natural frequency of the stretch spring.

     */

    private static final double NATURAL_FREQUENCY = 14.4222;



    /**

     * The damping ratio of the stretch spring.

     */

    private static final double DAMPING_RATIO = 0.875;



    /** @hide */

    @IntDef({TYPE_GLOW, TYPE_STRETCH})

    @Retention(RetentionPolicy.SOURCE)
@@ -119,13 +141,12 @@ public class EdgeEffect { 
    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)

    private float mGlowScaleY;

    private float mDistance;

    private float mVelocity; // only for stretch animations



    private float mGlowAlphaStart;

    private float mGlowAlphaFinish;

    private float mGlowScaleYStart;

    private float mGlowScaleYFinish;

    private float mDistanceStart;

    private float mDistanceFinish;



    private long mStartTime;

    private float mDuration;
@@ -239,6 +260,8 @@ public class EdgeEffect { 
     */

    public void finish() {

        mState = STATE_IDLE;

        mDistance = 0;

        mVelocity = 0;

    }



    /**
@@ -293,7 +316,8 @@ public class EdgeEffect { 
        mDuration = PULL_TIME;



        mPullDistance += deltaDistance;

        mDistanceStart = mDistanceFinish = mDistance = Math.max(0f, mPullDistance);

        mDistance = Math.max(0f, mPullDistance);

        mVelocity = 0;



        final float absdd = Math.abs(deltaDistance);

        mGlowAlpha = mGlowAlphaStart = Math.min(MAX_ALPHA,
@@ -387,11 +411,10 @@ public class EdgeEffect { 
        mState = STATE_RECEDE;

        mGlowAlphaStart = mGlowAlpha;

        mGlowScaleYStart = mGlowScaleY;

        mDistanceStart = mDistance;



        mGlowAlphaFinish = 0.f;

        mGlowScaleYFinish = 0.f;

        mDistanceFinish = 0.f;

        mVelocity = 0.f;



        mStartTime = AnimationUtils.currentAnimationTimeMillis();

        mDuration = RECEDE_TIME;
@@ -408,7 +431,14 @@ public class EdgeEffect { 
     * @param velocity Velocity at impact in pixels per second.

     */

    public void onAbsorb(int velocity) {

        if (mEdgeEffectType == TYPE_STRETCH) {

            mState = STATE_RECEDE;

            mVelocity = velocity / mHeight;

            mDistance = 0;

            mStartTime = AnimationUtils.currentAnimationTimeMillis();

        } else {

            mState = STATE_ABSORB;

            mVelocity = 0;

            velocity = Math.min(Math.max(MIN_VELOCITY, Math.abs(velocity)), MAX_VELOCITY);



            mStartTime = AnimationUtils.currentAnimationTimeMillis();
@@ -418,20 +448,19 @@ public class EdgeEffect { 
            // nearly invisible.

            mGlowAlphaStart = GLOW_ALPHA_START;

            mGlowScaleYStart = Math.max(mGlowScaleY, 0.f);

        mDistanceStart = mDistance;



            // Growth for the size of the glow should be quadratic to properly

            // respond

            // to a user's scrolling speed. The faster the scrolling speed, the more

            // intense the effect should be for both the size and the saturation.

        mGlowScaleYFinish = Math.min(0.025f + (velocity * (velocity / 100) * 0.00015f) / 2, 1.f);

            mGlowScaleYFinish = Math.min(0.025f + (velocity * (velocity / 100) * 0.00015f) / 2,

                    1.f);

            // Alpha should change for the glow as well as size.

            mGlowAlphaFinish = Math.max(

                mGlowAlphaStart, Math.min(velocity * VELOCITY_GLOW_FACTOR * .00001f, MAX_ALPHA));

                    mGlowAlphaStart,

                    Math.min(velocity * VELOCITY_GLOW_FACTOR * .00001f, MAX_ALPHA));

            mTargetDisplacement = 0.5f;



        // Use glow values to estimate the absorption for stretch distance.

        mDistanceFinish = calculateDistanceFromGlowValues(mGlowScaleYFinish, mGlowAlphaFinish);

        }

    }



    /**
@@ -539,8 +568,8 @@ public class EdgeEffect { 
            canvas.drawCircle(centerX, centerY, mRadius, mPaint);

            canvas.restoreToCount(count);

        } else if (canvas instanceof RecordingCanvas) {

            if (mState != STATE_PULL) {

                update();

            if (mState == STATE_RECEDE) {

                updateSpring();

            }

            RecordingCanvas recordingCanvas = (RecordingCanvas) canvas;

            if (mTmpMatrix == null) {
@@ -597,7 +626,7 @@ public class EdgeEffect { 
        }



        boolean oneLastFrame = false;

        if (mState == STATE_RECEDE && mDistance == 0) {

        if (mState == STATE_RECEDE && mDistance == 0 && mVelocity == 0) {

            mState = STATE_IDLE;

            oneLastFrame = true;

        }
@@ -634,7 +663,7 @@ public class EdgeEffect { 


        mGlowAlpha = mGlowAlphaStart + (mGlowAlphaFinish - mGlowAlphaStart) * interp;

        mGlowScaleY = mGlowScaleYStart + (mGlowScaleYFinish - mGlowScaleYStart) * interp;

        mDistance = mDistanceStart + (mDistanceFinish - mDistanceStart) * interp;

        mDistance = calculateDistanceFromGlowValues(mGlowScaleY, mGlowAlpha);

        mDisplacement = (mDisplacement + mTargetDisplacement) / 2;



        if (t >= 1.f - EPSILON) {
@@ -646,12 +675,10 @@ public class EdgeEffect { 


                    mGlowAlphaStart = mGlowAlpha;

                    mGlowScaleYStart = mGlowScaleY;

                    mDistanceStart = mDistance;



                    // After absorb, the glow should fade to nothing.

                    mGlowAlphaFinish = 0.f;

                    mGlowScaleYFinish = 0.f;

                    mDistanceFinish = 0.f;

                    break;

                case STATE_PULL:

                    mState = STATE_PULL_DECAY;
@@ -660,12 +687,10 @@ public class EdgeEffect { 


                    mGlowAlphaStart = mGlowAlpha;

                    mGlowScaleYStart = mGlowScaleY;

                    mDistanceStart = mDistance;



                    // After pull, the glow should fade to nothing.

                    mGlowAlphaFinish = 0.f;

                    mGlowScaleYFinish = 0.f;

                    mDistanceFinish = 0.f;

                    break;

                case STATE_PULL_DECAY:

                    mState = STATE_RECEDE;
@@ -677,6 +702,35 @@ public class EdgeEffect { 
        }

    }



    private void updateSpring() {

        final long time = AnimationUtils.currentAnimationTimeMillis();

        final float deltaT = (time - mStartTime) / 1000f; // Convert from millis to seconds

        if (deltaT < 0.001f) {

            return; // Must have at least 1 ms difference

        }

        final double mDampedFreq = NATURAL_FREQUENCY * Math.sqrt(1 - DAMPING_RATIO * DAMPING_RATIO);



        // We're always underdamped, so we can use only those equations:

        double cosCoeff = mDistance;

        double sinCoeff = (1 / mDampedFreq) * (DAMPING_RATIO * NATURAL_FREQUENCY

                * mDistance + mVelocity);

        double distance = Math.pow(Math.E, -DAMPING_RATIO * NATURAL_FREQUENCY * deltaT)

                * (cosCoeff * Math.cos(mDampedFreq * deltaT)

                + sinCoeff * Math.sin(mDampedFreq * deltaT));

        double velocity = distance * (-NATURAL_FREQUENCY) * DAMPING_RATIO

                + Math.pow(Math.E, -DAMPING_RATIO * NATURAL_FREQUENCY * deltaT)

                * (-mDampedFreq * cosCoeff * Math.sin(mDampedFreq * deltaT)

                + mDampedFreq * sinCoeff * Math.cos(mDampedFreq * deltaT));

        mDistance = (float) distance;

        mVelocity = (float) velocity;

        mStartTime = time;

        if (isAtEquilibrium()) {

            mState = STATE_IDLE;

            mDistance = 0;

            mVelocity = 0;

        }

    }



    /**

     * @return The estimated pull distance as calculated from mGlowScaleY.

     */
@@ -692,4 +746,15 @@ public class EdgeEffect { 
        }

        return alpha / PULL_DISTANCE_ALPHA_GLOW_FACTOR;

    }



    /**

     * @return true if the spring used for calculating the stretch animation is

     * considered at rest or false if it is still animating.

     */

    private boolean isAtEquilibrium() {

        double velocity = mVelocity * mHeight; // in pixels/second

        double displacement = mDistance * mHeight; // in pixels

        return Math.abs(velocity) < VELOCITY_THRESHOLD

                && Math.abs(displacement) < VALUE_THRESHOLD;

    }

}