diff options
Diffstat (limited to 'gallerycommon/src/com/android/gallery3d/common/Scroller.java')
-rw-r--r-- | gallerycommon/src/com/android/gallery3d/common/Scroller.java | 507 |
1 files changed, 0 insertions, 507 deletions
diff --git a/gallerycommon/src/com/android/gallery3d/common/Scroller.java b/gallerycommon/src/com/android/gallery3d/common/Scroller.java deleted file mode 100644 index 6cefd6fb0..000000000 --- a/gallerycommon/src/com/android/gallery3d/common/Scroller.java +++ /dev/null @@ -1,507 +0,0 @@ -/* - * 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); - } -} |