coco
129 lines
3.6 KiB
Java
129 lines
3.6 KiB
Java
/*
|
|
* Copyright 2013 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 lecho.lib.hellocharts.gesture;
|
|
|
|
import android.content.Context;
|
|
import android.os.SystemClock;
|
|
import android.view.animation.DecelerateInterpolator;
|
|
import android.view.animation.Interpolator;
|
|
|
|
/**
|
|
* A simple class that animates double-touch zoom gestures. Functionally similar to a {@link android.widget.Scroller}.
|
|
*/
|
|
public class ZoomerCompat {
|
|
private static final int DEFAULT_SHORT_ANIMATION_DURATION = 200;
|
|
/**
|
|
* The interpolator, used for making zooms animate 'naturally.'
|
|
*/
|
|
private Interpolator mInterpolator;
|
|
|
|
/**
|
|
* The total animation duration for a zoom.
|
|
*/
|
|
private long mAnimationDurationMillis;
|
|
|
|
/**
|
|
* Whether or not the current zoom has finished.
|
|
*/
|
|
private boolean mFinished = true;
|
|
|
|
/**
|
|
* The current zoom value; computed by {@link #computeZoom()}.
|
|
*/
|
|
private float mCurrentZoom;
|
|
|
|
/**
|
|
* The time the zoom started, computed using {@link android.os.SystemClock#elapsedRealtime()}.
|
|
*/
|
|
private long mStartRTC;
|
|
|
|
/**
|
|
* The destination zoom factor.
|
|
*/
|
|
private float mEndZoom;
|
|
|
|
public ZoomerCompat(Context context) {
|
|
mInterpolator = new DecelerateInterpolator();
|
|
// TODO: use constant
|
|
mAnimationDurationMillis = DEFAULT_SHORT_ANIMATION_DURATION;
|
|
}
|
|
|
|
/**
|
|
* Forces the zoom finished state to the given value. Unlike {@link #abortAnimation()}, the current zoom value isn't
|
|
* set to the ending value.
|
|
*
|
|
* @see android.widget.Scroller#forceFinished(boolean)
|
|
*/
|
|
public void forceFinished(boolean finished) {
|
|
mFinished = finished;
|
|
}
|
|
|
|
/**
|
|
* Aborts the animation, setting the current zoom value to the ending value.
|
|
*
|
|
* @see android.widget.Scroller#abortAnimation()
|
|
*/
|
|
public void abortAnimation() {
|
|
mFinished = true;
|
|
mCurrentZoom = mEndZoom;
|
|
}
|
|
|
|
/**
|
|
* Starts a zoom from 1.0 to (1.0 + endZoom). That is, to zoom from 100% to 125%, endZoom should by 0.25f.
|
|
*
|
|
* @see android.widget.Scroller#startScroll(int, int, int, int)
|
|
*/
|
|
public void startZoom(float endZoom) {
|
|
mStartRTC = SystemClock.elapsedRealtime();
|
|
mEndZoom = endZoom;
|
|
|
|
mFinished = false;
|
|
mCurrentZoom = 1f;
|
|
}
|
|
|
|
/**
|
|
* Computes the current zoom level, returning true if the zoom is still active and false if the zoom has finished.
|
|
*
|
|
* @see android.widget.Scroller#computeScrollOffset()
|
|
*/
|
|
public boolean computeZoom() {
|
|
if (mFinished) {
|
|
return false;
|
|
}
|
|
|
|
long tRTC = SystemClock.elapsedRealtime() - mStartRTC;
|
|
if (tRTC >= mAnimationDurationMillis) {
|
|
mFinished = true;
|
|
mCurrentZoom = mEndZoom;
|
|
return false;
|
|
}
|
|
|
|
float t = tRTC * 1f / mAnimationDurationMillis;
|
|
mCurrentZoom = mEndZoom * mInterpolator.getInterpolation(t);
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Returns the current zoom level.
|
|
*
|
|
* @see android.widget.Scroller#getCurrX()
|
|
*/
|
|
public float getCurrZoom() {
|
|
return mCurrentZoom;
|
|
}
|
|
}
|