| /* |
| * Copyright (C) 2019 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.systemui.statusbar.phone; |
| |
| import static android.view.Display.DEFAULT_DISPLAY; |
| |
| import android.content.res.Resources; |
| import android.graphics.Rect; |
| import android.os.Handler; |
| import android.view.CompositionSamplingListener; |
| import android.view.SurfaceControl; |
| import android.view.View; |
| import android.view.ViewRootImpl; |
| import android.view.ViewTreeObserver; |
| |
| import com.android.systemui.R; |
| |
| /** |
| * A helper class to sample regions on the screen and inspect its luminosity. |
| */ |
| public class RegionSamplingHelper implements View.OnAttachStateChangeListener, |
| View.OnLayoutChangeListener { |
| |
| private final Handler mHandler = new Handler(); |
| private final View mSampledView; |
| |
| private final CompositionSamplingListener mSamplingListener; |
| private final Runnable mUpdateSamplingListener = this::updateSamplingListener; |
| |
| /** |
| * The requested sampling bounds that we want to sample from |
| */ |
| private final Rect mSamplingRequestBounds = new Rect(); |
| |
| /** |
| * The sampling bounds that are currently registered. |
| */ |
| private final Rect mRegisteredSamplingBounds = new Rect(); |
| private final SamplingCallback mCallback; |
| private boolean mSamplingEnabled = false; |
| private boolean mSamplingListenerRegistered = false; |
| |
| private float mLastMedianLuma; |
| private float mCurrentMedianLuma; |
| private boolean mWaitingOnDraw; |
| |
| // Passing the threshold of this luminance value will make the button black otherwise white |
| private final float mLuminanceThreshold; |
| private final float mLuminanceChangeThreshold; |
| private boolean mFirstSamplingAfterStart; |
| private SurfaceControl mRegisteredStopLayer = null; |
| private ViewTreeObserver.OnDrawListener mUpdateOnDraw = new ViewTreeObserver.OnDrawListener() { |
| @Override |
| public void onDraw() { |
| // We need to post the remove runnable, since it's not allowed to remove in onDraw |
| mHandler.post(mRemoveDrawRunnable); |
| RegionSamplingHelper.this.onDraw(); |
| } |
| }; |
| private Runnable mRemoveDrawRunnable = new Runnable() { |
| @Override |
| public void run() { |
| mSampledView.getViewTreeObserver().removeOnDrawListener(mUpdateOnDraw); |
| } |
| }; |
| |
| public RegionSamplingHelper(View sampledView, SamplingCallback samplingCallback) { |
| mSamplingListener = new CompositionSamplingListener( |
| sampledView.getContext().getMainExecutor()) { |
| @Override |
| public void onSampleCollected(float medianLuma) { |
| if (mSamplingEnabled) { |
| updateMediaLuma(medianLuma); |
| } |
| } |
| }; |
| mSampledView = sampledView; |
| mSampledView.addOnAttachStateChangeListener(this); |
| mSampledView.addOnLayoutChangeListener(this); |
| |
| final Resources res = sampledView.getResources(); |
| mLuminanceThreshold = res.getFloat(R.dimen.navigation_luminance_threshold); |
| mLuminanceChangeThreshold = res.getFloat(R.dimen.navigation_luminance_change_threshold); |
| mCallback = samplingCallback; |
| } |
| |
| private void onDraw() { |
| if (mWaitingOnDraw) { |
| mWaitingOnDraw = false; |
| updateSamplingListener(); |
| } |
| } |
| |
| void start(Rect initialSamplingBounds) { |
| if (!mCallback.isSamplingEnabled()) { |
| return; |
| } |
| if (initialSamplingBounds != null) { |
| mSamplingRequestBounds.set(initialSamplingBounds); |
| } |
| mSamplingEnabled = true; |
| // make sure we notify once |
| mLastMedianLuma = -1; |
| mFirstSamplingAfterStart = true; |
| updateSamplingListener(); |
| } |
| |
| void stop() { |
| mSamplingEnabled = false; |
| updateSamplingListener(); |
| } |
| |
| @Override |
| public void onViewAttachedToWindow(View view) { |
| updateSamplingListener(); |
| } |
| |
| @Override |
| public void onViewDetachedFromWindow(View view) { |
| // isAttachedToWindow is only changed after this call to the listeners, so let's post it |
| // instead |
| postUpdateSamplingListener(); |
| } |
| |
| @Override |
| public void onLayoutChange(View v, int left, int top, int right, int bottom, |
| int oldLeft, int oldTop, int oldRight, int oldBottom) { |
| updateSamplingRect(); |
| } |
| |
| private void postUpdateSamplingListener() { |
| mHandler.removeCallbacks(mUpdateSamplingListener); |
| mHandler.post(mUpdateSamplingListener); |
| } |
| |
| private void updateSamplingListener() { |
| boolean isSamplingEnabled = mSamplingEnabled && !mSamplingRequestBounds.isEmpty() |
| && (mSampledView.isAttachedToWindow() || mFirstSamplingAfterStart); |
| if (isSamplingEnabled) { |
| ViewRootImpl viewRootImpl = mSampledView.getViewRootImpl(); |
| SurfaceControl stopLayerControl = null; |
| if (viewRootImpl != null) { |
| stopLayerControl = viewRootImpl.getSurfaceControl(); |
| } |
| if (stopLayerControl == null || !stopLayerControl.isValid()) { |
| if (!mWaitingOnDraw) { |
| mWaitingOnDraw = true; |
| // The view might be attached but we haven't drawn yet, so wait until the |
| // next draw to update the listener again with the stop layer, such that our |
| // own drawing doesn't affect the sampling. |
| if (mHandler.hasCallbacks(mRemoveDrawRunnable)) { |
| mHandler.removeCallbacks(mRemoveDrawRunnable); |
| } else { |
| mSampledView.getViewTreeObserver().addOnDrawListener(mUpdateOnDraw); |
| } |
| } |
| // If there's no valid surface, let's just sample without a stop layer, so we |
| // don't have to delay |
| stopLayerControl = null; |
| } |
| if (!mSamplingRequestBounds.equals(mRegisteredSamplingBounds) |
| || mRegisteredStopLayer != stopLayerControl) { |
| // We only want to reregister if something actually changed |
| unregisterSamplingListener(); |
| mSamplingListenerRegistered = true; |
| CompositionSamplingListener.register(mSamplingListener, DEFAULT_DISPLAY, |
| stopLayerControl, mSamplingRequestBounds); |
| mRegisteredSamplingBounds.set(mSamplingRequestBounds); |
| mRegisteredStopLayer = stopLayerControl; |
| } |
| mFirstSamplingAfterStart = false; |
| } else { |
| unregisterSamplingListener(); |
| } |
| } |
| |
| private void unregisterSamplingListener() { |
| if (mSamplingListenerRegistered) { |
| mSamplingListenerRegistered = false; |
| mRegisteredStopLayer = null; |
| mRegisteredSamplingBounds.setEmpty(); |
| CompositionSamplingListener.unregister(mSamplingListener); |
| } |
| } |
| |
| private void updateMediaLuma(float medianLuma) { |
| mCurrentMedianLuma = medianLuma; |
| |
| // If the difference between the new luma and the current luma is larger than threshold |
| // then apply the current luma, this is to prevent small changes causing colors to flicker |
| if (Math.abs(mCurrentMedianLuma - mLastMedianLuma) > mLuminanceChangeThreshold) { |
| mCallback.onRegionDarknessChanged(medianLuma < mLuminanceThreshold /* isRegionDark */); |
| mLastMedianLuma = medianLuma; |
| } |
| } |
| |
| public void updateSamplingRect() { |
| Rect sampledRegion = mCallback.getSampledRegion(mSampledView); |
| if (!mSamplingRequestBounds.equals(sampledRegion)) { |
| mSamplingRequestBounds.set(sampledRegion); |
| updateSamplingListener(); |
| } |
| } |
| |
| public interface SamplingCallback { |
| /** |
| * Called when the darkness of the sampled region changes |
| * @param isRegionDark true if the sampled luminance is below the luminance threshold |
| */ |
| void onRegionDarknessChanged(boolean isRegionDark); |
| |
| /** |
| * Get the sampled region of interest from the sampled view |
| * @param sampledView The view that this helper is attached to for convenience |
| * @return the region to be sampled in sceen coordinates. Return {@code null} to avoid |
| * sampling in this frame |
| */ |
| Rect getSampledRegion(View sampledView); |
| |
| /** |
| * @return if sampling should be enabled in the current configuration |
| */ |
| default boolean isSamplingEnabled() { |
| return true; |
| } |
| } |
| } |