diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/FlingAnimationUtils.java b/packages/SystemUI/src/com/android/systemui/statusbar/FlingAnimationUtils.java index bb3a295a8c438..7d576cb342433 100644 --- a/packages/SystemUI/src/com/android/systemui/statusbar/FlingAnimationUtils.java +++ b/packages/SystemUI/src/com/android/systemui/statusbar/FlingAnimationUtils.java @@ -28,33 +28,35 @@ import android.view.animation.PathInterpolator; public class FlingAnimationUtils { private static final float LINEAR_OUT_SLOW_IN_X2 = 0.35f; - private static final float LINEAR_OUT_FASTER_IN_Y2 = 0.7f; + private static final float LINEAR_OUT_FASTER_IN_Y2_MIN = 0.7f; + private static final float LINEAR_OUT_FASTER_IN_Y2_MAX = 1f; private static final float MIN_VELOCITY_DP_PER_SECOND = 250; + private static final float HIGH_VELOCITY_DP_PER_SECOND = 3000; /** * Crazy math. http://en.wikipedia.org/wiki/B%C3%A9zier_curve */ private static final float LINEAR_OUT_SLOW_IN_START_GRADIENT = 1.0f / LINEAR_OUT_SLOW_IN_X2; - private static final float LINEAR_OUT_FASTER_IN_START_GRADIENT = LINEAR_OUT_FASTER_IN_Y2; private Interpolator mLinearOutSlowIn; private Interpolator mFastOutSlowIn; private Interpolator mFastOutLinearIn; - private Interpolator mLinearOutFasterIn; private float mMinVelocityPxPerSecond; private float mMaxLengthSeconds; + private float mHighVelocityPxPerSecond; public FlingAnimationUtils(Context ctx, float maxLengthSeconds) { mMaxLengthSeconds = maxLengthSeconds; mLinearOutSlowIn = new PathInterpolator(0, 0, LINEAR_OUT_SLOW_IN_X2, 1); - mLinearOutFasterIn = new PathInterpolator(0, 0, 1, LINEAR_OUT_FASTER_IN_Y2); mFastOutSlowIn = AnimationUtils.loadInterpolator(ctx, android.R.interpolator.fast_out_slow_in); mFastOutLinearIn = AnimationUtils.loadInterpolator(ctx, android.R.interpolator.fast_out_linear_in); mMinVelocityPxPerSecond = MIN_VELOCITY_DP_PER_SECOND * ctx.getResources().getDisplayMetrics().density; + mHighVelocityPxPerSecond + = HIGH_VELOCITY_DP_PER_SECOND * ctx.getResources().getDisplayMetrics().density; } /** @@ -126,7 +128,12 @@ public class FlingAnimationUtils { * Math.pow(Math.abs(endValue - currValue) / maxDistance, 0.5f)); float diff = Math.abs(endValue - currValue); float velAbs = Math.abs(velocity); - float durationSeconds = LINEAR_OUT_FASTER_IN_START_GRADIENT * diff / velAbs; + float y2 = calculateLinearOutFasterInY2(velAbs); + + // The gradient at the start of the curve is just y2. + float startGradient = y2; + Interpolator mLinearOutFasterIn = new PathInterpolator(0, 0, 1, y2); + float durationSeconds = startGradient * diff / velAbs; if (durationSeconds <= maxLengthSeconds) { animator.setInterpolator(mLinearOutFasterIn); } else if (velAbs >= mMinVelocityPxPerSecond) { @@ -148,6 +155,20 @@ public class FlingAnimationUtils { animator.setDuration((long) (durationSeconds * 1000)); } + /** + * Calculates the y2 control point for a linear-out-faster-in path interpolator depending on the + * velocity. The faster the velocity, the more "linear" the interpolator gets. + * + * @param velocity the velocity of the gesture. + * @return the y2 control point for a cubic bezier path interpolator + */ + private float calculateLinearOutFasterInY2(float velocity) { + float t = (velocity - mMinVelocityPxPerSecond) + / (mHighVelocityPxPerSecond - mMinVelocityPxPerSecond); + t = Math.max(0, Math.min(1, t)); + return (1 - t) * LINEAR_OUT_FASTER_IN_Y2_MIN + t * LINEAR_OUT_FASTER_IN_Y2_MAX; + } + /** * @return the minimum velocity a gesture needs to have to be considered a fling */