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diff --git a/gallerycommon/src/com/android/gallery3d/common/Scroller.java b/gallerycommon/src/com/android/gallery3d/common/Scroller.java
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-/*
- * Copyright (C) 2006 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.gallery3d.common;
-
-import android.content.Context;
-import android.hardware.SensorManager;
-import android.os.Build;
-import android.util.FloatMath;
-import android.view.ViewConfiguration;
-import android.view.animation.AnimationUtils;
-import android.view.animation.Interpolator;
-
-
-/**
- * This class encapsulates scrolling. The duration of the scroll
- * can be passed in the constructor and specifies the maximum time that
- * the scrolling animation should take. Past this time, the scrolling is
- * automatically moved to its final stage and computeScrollOffset()
- * will always return false to indicate that scrolling is over.
- */
-public class Scroller {
- private int mMode;
-
- private int mStartX;
- private int mStartY;
- private int mFinalX;
- private int mFinalY;
-
- private int mMinX;
- private int mMaxX;
- private int mMinY;
- private int mMaxY;
-
- private int mCurrX;
- private int mCurrY;
- private long mStartTime;
- private int mDuration;
- private float mDurationReciprocal;
- private float mDeltaX;
- private float mDeltaY;
- private boolean mFinished;
- private Interpolator mInterpolator;
- private boolean mFlywheel;
-
- private float mVelocity;
-
- private static final int DEFAULT_DURATION = 250;
- private static final int SCROLL_MODE = 0;
- private static final int FLING_MODE = 1;
-
- private static float DECELERATION_RATE = (float) (Math.log(0.75) / Math.log(0.9));
- private static float ALPHA = 800; // pixels / seconds
- private static float START_TENSION = 0.4f; // Tension at start: (0.4 * total T, 1.0 * Distance)
- private static float END_TENSION = 1.0f - START_TENSION;
- private static final int NB_SAMPLES = 100;
- private static final float[] SPLINE = new float[NB_SAMPLES + 1];
-
- private float mDeceleration;
- private final float mPpi;
-
- static {
- float x_min = 0.0f;
- for (int i = 0; i <= NB_SAMPLES; i++) {
- final float t = (float) i / NB_SAMPLES;
- float x_max = 1.0f;
- float x, tx, coef;
- while (true) {
- x = x_min + (x_max - x_min) / 2.0f;
- coef = 3.0f * x * (1.0f - x);
- tx = coef * ((1.0f - x) * START_TENSION + x * END_TENSION) + x * x * x;
- if (Math.abs(tx - t) < 1E-5) break;
- if (tx > t) x_max = x;
- else x_min = x;
- }
- final float d = coef + x * x * x;
- SPLINE[i] = d;
- }
- SPLINE[NB_SAMPLES] = 1.0f;
-
- // This controls the viscous fluid effect (how much of it)
- sViscousFluidScale = 8.0f;
- // must be set to 1.0 (used in viscousFluid())
- sViscousFluidNormalize = 1.0f;
- sViscousFluidNormalize = 1.0f / viscousFluid(1.0f);
- }
-
- private static float sViscousFluidScale;
- private static float sViscousFluidNormalize;
-
- /**
- * Create a Scroller with the default duration and interpolator.
- */
- public Scroller(Context context) {
- this(context, null);
- }
-
- /**
- * Create a Scroller with the specified interpolator. If the interpolator is
- * null, the default (viscous) interpolator will be used. "Flywheel" behavior will
- * be in effect for apps targeting Honeycomb or newer.
- */
- public Scroller(Context context, Interpolator interpolator) {
- this(context, interpolator,
- context.getApplicationInfo().targetSdkVersion >= Build.VERSION_CODES.HONEYCOMB);
- }
-
- /**
- * Create a Scroller with the specified interpolator. If the interpolator is
- * null, the default (viscous) interpolator will be used. Specify whether or
- * not to support progressive "flywheel" behavior in flinging.
- */
- public Scroller(Context context, Interpolator interpolator, boolean flywheel) {
- mFinished = true;
- mInterpolator = interpolator;
- mPpi = context.getResources().getDisplayMetrics().density * 160.0f;
- mDeceleration = computeDeceleration(ViewConfiguration.getScrollFriction());
- mFlywheel = flywheel;
- }
-
- /**
- * The amount of friction applied to flings. The default value
- * is {@link ViewConfiguration#getScrollFriction}.
- *
- * @param friction A scalar dimension-less value representing the coefficient of
- * friction.
- */
- public final void setFriction(float friction) {
- mDeceleration = computeDeceleration(friction);
- }
-
- private float computeDeceleration(float friction) {
- return SensorManager.GRAVITY_EARTH // g (m/s^2)
- * 39.37f // inch/meter
- * mPpi // pixels per inch
- * friction;
- }
-
- /**
- *
- * Returns whether the scroller has finished scrolling.
- *
- * @return True if the scroller has finished scrolling, false otherwise.
- */
- public final boolean isFinished() {
- return mFinished;
- }
-
- /**
- * Force the finished field to a particular value.
- *
- * @param finished The new finished value.
- */
- public final void forceFinished(boolean finished) {
- mFinished = finished;
- }
-
- /**
- * Returns how long the scroll event will take, in milliseconds.
- *
- * @return The duration of the scroll in milliseconds.
- */
- public final int getDuration() {
- return mDuration;
- }
-
- /**
- * Returns the current X offset in the scroll.
- *
- * @return The new X offset as an absolute distance from the origin.
- */
- public final int getCurrX() {
- return mCurrX;
- }
-
- /**
- * Returns the current Y offset in the scroll.
- *
- * @return The new Y offset as an absolute distance from the origin.
- */
- public final int getCurrY() {
- return mCurrY;
- }
-
- /**
- * Returns the current velocity.
- *
- * @return The original velocity less the deceleration. Result may be
- * negative.
- */
- public float getCurrVelocity() {
- return mVelocity - mDeceleration * timePassed() / 2000.0f;
- }
-
- /**
- * Returns the start X offset in the scroll.
- *
- * @return The start X offset as an absolute distance from the origin.
- */
- public final int getStartX() {
- return mStartX;
- }
-
- /**
- * Returns the start Y offset in the scroll.
- *
- * @return The start Y offset as an absolute distance from the origin.
- */
- public final int getStartY() {
- return mStartY;
- }
-
- /**
- * Returns where the scroll will end. Valid only for "fling" scrolls.
- *
- * @return The final X offset as an absolute distance from the origin.
- */
- public final int getFinalX() {
- return mFinalX;
- }
-
- /**
- * Returns where the scroll will end. Valid only for "fling" scrolls.
- *
- * @return The final Y offset as an absolute distance from the origin.
- */
- public final int getFinalY() {
- return mFinalY;
- }
-
- /**
- * Call this when you want to know the new location. If it returns true,
- * the animation is not yet finished. loc will be altered to provide the
- * new location.
- */
- public boolean computeScrollOffset() {
- if (mFinished) {
- return false;
- }
-
- int timePassed = (int)(AnimationUtils.currentAnimationTimeMillis() - mStartTime);
-
- if (timePassed < mDuration) {
- switch (mMode) {
- case SCROLL_MODE:
- float x = timePassed * mDurationReciprocal;
-
- if (mInterpolator == null)
- x = viscousFluid(x);
- else
- x = mInterpolator.getInterpolation(x);
-
- mCurrX = mStartX + Math.round(x * mDeltaX);
- mCurrY = mStartY + Math.round(x * mDeltaY);
- break;
- case FLING_MODE:
- final float t = (float) timePassed / mDuration;
- final int index = (int) (NB_SAMPLES * t);
- final float t_inf = (float) index / NB_SAMPLES;
- final float t_sup = (float) (index + 1) / NB_SAMPLES;
- final float d_inf = SPLINE[index];
- final float d_sup = SPLINE[index + 1];
- final float distanceCoef = d_inf + (t - t_inf) / (t_sup - t_inf) * (d_sup - d_inf);
-
- mCurrX = mStartX + Math.round(distanceCoef * (mFinalX - mStartX));
- // Pin to mMinX <= mCurrX <= mMaxX
- mCurrX = Math.min(mCurrX, mMaxX);
- mCurrX = Math.max(mCurrX, mMinX);
-
- mCurrY = mStartY + Math.round(distanceCoef * (mFinalY - mStartY));
- // Pin to mMinY <= mCurrY <= mMaxY
- mCurrY = Math.min(mCurrY, mMaxY);
- mCurrY = Math.max(mCurrY, mMinY);
-
- if (mCurrX == mFinalX && mCurrY == mFinalY) {
- mFinished = true;
- }
-
- break;
- }
- }
- else {
- mCurrX = mFinalX;
- mCurrY = mFinalY;
- mFinished = true;
- }
- return true;
- }
-
- /**
- * Start scrolling by providing a starting point and the distance to travel.
- * The scroll will use the default value of 250 milliseconds for the
- * duration.
- *
- * @param startX Starting horizontal scroll offset in pixels. Positive
- * numbers will scroll the content to the left.
- * @param startY Starting vertical scroll offset in pixels. Positive numbers
- * will scroll the content up.
- * @param dx Horizontal distance to travel. Positive numbers will scroll the
- * content to the left.
- * @param dy Vertical distance to travel. Positive numbers will scroll the
- * content up.
- */
- public void startScroll(int startX, int startY, int dx, int dy) {
- startScroll(startX, startY, dx, dy, DEFAULT_DURATION);
- }
-
- /**
- * Start scrolling by providing a starting point and the distance to travel.
- *
- * @param startX Starting horizontal scroll offset in pixels. Positive
- * numbers will scroll the content to the left.
- * @param startY Starting vertical scroll offset in pixels. Positive numbers
- * will scroll the content up.
- * @param dx Horizontal distance to travel. Positive numbers will scroll the
- * content to the left.
- * @param dy Vertical distance to travel. Positive numbers will scroll the
- * content up.
- * @param duration Duration of the scroll in milliseconds.
- */
- public void startScroll(int startX, int startY, int dx, int dy, int duration) {
- mMode = SCROLL_MODE;
- mFinished = false;
- mDuration = duration;
- mStartTime = AnimationUtils.currentAnimationTimeMillis();
- mStartX = startX;
- mStartY = startY;
- mFinalX = startX + dx;
- mFinalY = startY + dy;
- mDeltaX = dx;
- mDeltaY = dy;
- mDurationReciprocal = 1.0f / mDuration;
- }
-
- /**
- * Start scrolling based on a fling gesture. The distance travelled will
- * depend on the initial velocity of the fling.
- *
- * @param startX Starting point of the scroll (X)
- * @param startY Starting point of the scroll (Y)
- * @param velocityX Initial velocity of the fling (X) measured in pixels per
- * second.
- * @param velocityY Initial velocity of the fling (Y) measured in pixels per
- * second
- * @param minX Minimum X value. The scroller will not scroll past this
- * point.
- * @param maxX Maximum X value. The scroller will not scroll past this
- * point.
- * @param minY Minimum Y value. The scroller will not scroll past this
- * point.
- * @param maxY Maximum Y value. The scroller will not scroll past this
- * point.
- */
- public void fling(int startX, int startY, int velocityX, int velocityY,
- int minX, int maxX, int minY, int maxY) {
- // Continue a scroll or fling in progress
- if (mFlywheel && !mFinished) {
- float oldVel = getCurrVelocity();
-
- float dx = mFinalX - mStartX;
- float dy = mFinalY - mStartY;
- float hyp = FloatMath.sqrt(dx * dx + dy * dy);
-
- float ndx = dx / hyp;
- float ndy = dy / hyp;
-
- float oldVelocityX = ndx * oldVel;
- float oldVelocityY = ndy * oldVel;
- if (Math.signum(velocityX) == Math.signum(oldVelocityX) &&
- Math.signum(velocityY) == Math.signum(oldVelocityY)) {
- velocityX += oldVelocityX;
- velocityY += oldVelocityY;
- }
- }
-
- mMode = FLING_MODE;
- mFinished = false;
-
- float velocity = FloatMath.sqrt(velocityX * velocityX + velocityY * velocityY);
-
- mVelocity = velocity;
- final double l = Math.log(START_TENSION * velocity / ALPHA);
- mDuration = (int) (1000.0 * Math.exp(l / (DECELERATION_RATE - 1.0)));
- mStartTime = AnimationUtils.currentAnimationTimeMillis();
- mStartX = startX;
- mStartY = startY;
-
- float coeffX = velocity == 0 ? 1.0f : velocityX / velocity;
- float coeffY = velocity == 0 ? 1.0f : velocityY / velocity;
-
- int totalDistance =
- (int) (ALPHA * Math.exp(DECELERATION_RATE / (DECELERATION_RATE - 1.0) * l));
-
- mMinX = minX;
- mMaxX = maxX;
- mMinY = minY;
- mMaxY = maxY;
-
- mFinalX = startX + Math.round(totalDistance * coeffX);
- // Pin to mMinX <= mFinalX <= mMaxX
- mFinalX = Math.min(mFinalX, mMaxX);
- mFinalX = Math.max(mFinalX, mMinX);
-
- mFinalY = startY + Math.round(totalDistance * coeffY);
- // Pin to mMinY <= mFinalY <= mMaxY
- mFinalY = Math.min(mFinalY, mMaxY);
- mFinalY = Math.max(mFinalY, mMinY);
- }
-
- static float viscousFluid(float x)
- {
- x *= sViscousFluidScale;
- if (x < 1.0f) {
- x -= (1.0f - (float)Math.exp(-x));
- } else {
- float start = 0.36787944117f; // 1/e == exp(-1)
- x = 1.0f - (float)Math.exp(1.0f - x);
- x = start + x * (1.0f - start);
- }
- x *= sViscousFluidNormalize;
- return x;
- }
-
- /**
- * Stops the animation. Contrary to {@link #forceFinished(boolean)},
- * aborting the animating cause the scroller to move to the final x and y
- * position
- *
- * @see #forceFinished(boolean)
- */
- public void abortAnimation() {
- mCurrX = mFinalX;
- mCurrY = mFinalY;
- mFinished = true;
- }
-
- /**
- * Extend the scroll animation. This allows a running animation to scroll
- * further and longer, when used with {@link #setFinalX(int)} or {@link #setFinalY(int)}.
- *
- * @param extend Additional time to scroll in milliseconds.
- * @see #setFinalX(int)
- * @see #setFinalY(int)
- */
- public void extendDuration(int extend) {
- int passed = timePassed();
- mDuration = passed + extend;
- mDurationReciprocal = 1.0f / mDuration;
- mFinished = false;
- }
-
- /**
- * Returns the time elapsed since the beginning of the scrolling.
- *
- * @return The elapsed time in milliseconds.
- */
- public int timePassed() {
- return (int)(AnimationUtils.currentAnimationTimeMillis() - mStartTime);
- }
-
- /**
- * Sets the final position (X) for this scroller.
- *
- * @param newX The new X offset as an absolute distance from the origin.
- * @see #extendDuration(int)
- * @see #setFinalY(int)
- */
- public void setFinalX(int newX) {
- mFinalX = newX;
- mDeltaX = mFinalX - mStartX;
- mFinished = false;
- }
-
- /**
- * Sets the final position (Y) for this scroller.
- *
- * @param newY The new Y offset as an absolute distance from the origin.
- * @see #extendDuration(int)
- * @see #setFinalX(int)
- */
- public void setFinalY(int newY) {
- mFinalY = newY;
- mDeltaY = mFinalY - mStartY;
- mFinished = false;
- }
-
- /**
- * @hide
- */
- public boolean isScrollingInDirection(float xvel, float yvel) {
- return !mFinished && Math.signum(xvel) == Math.signum(mFinalX - mStartX) &&
- Math.signum(yvel) == Math.signum(mFinalY - mStartY);
- }
-}