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/*
* Copyright (C) 2014 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.camera.ui.motion;
import android.graphics.Canvas;
import java.util.ArrayList;
import java.util.List;
/**
* Designed to handle the lifecycle of a view that needs a continuous update /
* redraw cycle that does not have a defined start / end time.
*
* Fixed length animations should NOT use this class.
*/
public class DynamicAnimator implements Invalidator {
public final List<DynamicAnimation> animations = new ArrayList<>();
private final Invalidator mInvalidator;
private final AnimationClock mClock;
private boolean mUpdateRequested = false;
private boolean mIsDrawing = false;
private long mLastDrawTimeMillis = 0;
private long mDrawTimeMillis = 0;
public DynamicAnimator(Invalidator invalidator, AnimationClock clock) {
mInvalidator = invalidator;
mClock = clock;
}
public void draw(Canvas canvas) {
mIsDrawing = true;
mUpdateRequested = false;
mDrawTimeMillis = mClock.getTimeMillis();
if (mLastDrawTimeMillis <= 0) {
mLastDrawTimeMillis = mDrawTimeMillis; // On the initial draw, dt is zero.
}
long dt = mDrawTimeMillis - mLastDrawTimeMillis;
mLastDrawTimeMillis = mDrawTimeMillis;
// Run the animation
for (DynamicAnimation renderer : animations) {
if (renderer.isActive()) {
renderer.draw(mDrawTimeMillis, dt, canvas);
}
}
// If either the update or the draw methods requested new frames, then
// invalidate the view which should give us another frame to work with.
// Otherwise, stopAt the last update time.
if (mUpdateRequested) {
mInvalidator.invalidate();
} else {
mLastDrawTimeMillis = -1;
}
mIsDrawing = false;
}
/**
* If a scheduleNewFrame request comes in outside of the animation loop,
* and we didn't schedule a frame after the previous loop (or it's the
* first time we've used this instance), invalidate the view and set the
* last update time to the current time. Theoretically, a few milliseconds
* have elapsed before the view gets updated.
*/
@Override
public void invalidate() {
if (!mIsDrawing && !mUpdateRequested) {
mInvalidator.invalidate();
mLastDrawTimeMillis = mClock.getTimeMillis();
}
mUpdateRequested = true;
}
/**
* This will return the "best guess" for the most current animation frame
* time. If the loop is currently drawing, then it will return the time the
* draw began, and if an update is currently requested it will return the
* time that the update was requested at, and if neither of these are true
* it will return the current system clock time.
*
* This method will not trigger a new update.
*/
public long getTimeMillis() {
if (mIsDrawing) {
return mDrawTimeMillis;
}
if (mUpdateRequested) {
return mLastDrawTimeMillis;
}
return mClock.getTimeMillis();
}
}
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