PawletOS/Lawnchair
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Merge changes from topic "am-cf9638ae-d2ec-4b5a-94ac-d1ce047249a4" into ub-launcher3-master

Browse Source 
* changes:
  [automerger] Swipe up overshoot always plays am: cc3755da6e
  Swipe up overshoot always plays
This commit is contained in:
Tony Wickham
2018-06-27 21:00:54 +00:00
committed by Android (Google) Code Review
parent 74a7e6a3d8 002560dee7
commit ebb20bfdaa
3 changed files with 133 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/com/android/launcher3/anim/Interpolators.java
+75 -7
View File
@@ -16,7 +16,10 @@
package com.android.launcher3.anim;
import static com.android.launcher3.Utilities.SINGLE_FRAME_MS;
import android.graphics.Path;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.view.animation.AccelerateInterpolator;
import android.view.animation.DecelerateInterpolator;
import android.view.animation.Interpolator;
@@ -45,6 +48,8 @@ public class Interpolators {
public static final Interpolator DEACCEL_2_5 = new DecelerateInterpolator(2.5f);
public static final Interpolator DEACCEL_3 = new DecelerateInterpolator(3f);
public static final Interpolator ACCEL_DEACCEL = new AccelerateDecelerateInterpolator();
public static final Interpolator FAST_OUT_SLOW_IN = new PathInterpolator(0.4f, 0f, 0.2f, 1f);
public static final Interpolator AGGRESSIVE_EASE = new PathInterpolator(0.2f, 0f, 0f, 1f);
@@ -118,17 +123,12 @@ public class Interpolators {
return Math.abs(velocity) > FAST_FLING_PX_MS ? SCROLL : SCROLL_CUBIC;
}
public static Interpolator overshootInterpolatorForVelocity(float velocity) {
return overshootInterpolatorForVelocity(velocity, 1f);
}
/**
* Create an OvershootInterpolator with tension directly related to the velocity (in px/ms).
* @param velocity The start velocity of the animation we want to overshoot.
* @param dampFactor An optional factor to reduce the amount of tension (how far we overshoot).
*/
public static Interpolator overshootInterpolatorForVelocity(float velocity, float dampFactor) {
return new OvershootInterpolator(Math.min(Math.abs(velocity), 3f) / dampFactor);
public static Interpolator overshootInterpolatorForVelocity(float velocity) {
return new OvershootInterpolator(Math.min(Math.abs(velocity), 3f));
}
/**
@@ -160,4 +160,72 @@ public class Interpolators {
float upperBound) {
return t -> Utilities.mapRange(interpolator.getInterpolation(t), lowerBound, upperBound);
}
/**
* Computes parameters necessary for an overshoot effect.
*/
public static class OvershootParams {
public Interpolator interpolator;
public float start;
public float end;
public long duration;
/**
* Given the input params, sets OvershootParams variables to be used by the caller.
* @param startProgress The progress from 0 to 1 that the overshoot starts from.
* @param overshootPastProgress The progress from 0 to 1 where we overshoot past (should
* either be equal to startProgress or endProgress, depending on if we want to
* overshoot immediately or only once we reach the end).
* @param endProgress The final progress from 0 to 1 that we will settle to.
* @param velocityPxPerMs The initial velocity that causes this overshoot.
* @param totalDistancePx The distance against which progress is calculated.
*/
public OvershootParams(float startProgress, float overshootPastProgress,
float endProgress, float velocityPxPerMs, int totalDistancePx) {
velocityPxPerMs = Math.abs(velocityPxPerMs);
start = startProgress;
int startPx = (int) (start * totalDistancePx);
// Overshoot by about half a frame.
float overshootBy = velocityPxPerMs * SINGLE_FRAME_MS / totalDistancePx / 2;
overshootBy = Utilities.boundToRange(overshootBy, 0.02f, 0.15f);
end = overshootPastProgress + overshootBy;
int endPx = (int) (end * totalDistancePx);
int overshootDistance = endPx - startPx;
// Calculate deceleration necessary to reach overshoot distance.
// Formula: velocityFinal^2 = velocityInitial^2 + 2 * acceleration * distance
// 0 = v^2 + 2ad (velocityFinal == 0)
// a = v^2 / -2d
float decelerationPxPerMs = velocityPxPerMs * velocityPxPerMs / (2 * overshootDistance);
// Calculate time necessary to reach peak of overshoot.
// Formula: acceleration = velocity / time
// time = velocity / acceleration
duration = (long) (velocityPxPerMs / decelerationPxPerMs);
// Now that we're at the top of the overshoot, need to settle back to endProgress.
float settleDistance = end - endProgress;
int settleDistancePx = (int) (settleDistance * totalDistancePx);
// Calculate time necessary for the settle.
// Formula: distance = velocityInitial * time + 1/2 * acceleration * time^2
// d = 1/2at^2 (velocityInitial = 0, since we just stopped at the top)
// t = sqrt(2d/a)
// Above formula assumes constant acceleration. Since we use ACCEL_DEACCEL, we actually
// have acceleration to halfway then deceleration the rest. So the formula becomes:
// t = sqrt(d/a) * 2 (half the distance for accel, half for deaccel)
long settleDuration = (long) Math.sqrt(settleDistancePx / decelerationPxPerMs) * 2;
// How much of the animation to devote to playing the overshoot (the rest is for settle).
float overshootFraction = (float) duration / (duration + settleDuration);
duration += settleDuration;
// Finally, create the interpolator, composed of two interpolators: an overshoot, which
// reaches end > 1, and then a settle to endProgress.
Interpolator overshoot = Interpolators.clampToProgress(DEACCEL, 0, overshootFraction);
// The settle starts at 1, where 1 is the top of the overshoot, and maps to a fraction
// such that final progress is endProgress. For example, if we overshot to 1.1 but want
// to end at 1, we need to map to 1/1.1.
Interpolator settle = Interpolators.clampToProgress(Interpolators.mapToProgress(
ACCEL_DEACCEL, 1, (endProgress - start) / (end - start)), overshootFraction, 1);
interpolator = t -> t <= overshootFraction
? overshoot.getInterpolation(t)
: settle.getInterpolation(t);
}
}
}