DisplayInfoManager.java
/*
* Copyright 2021 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 androidx.camera.camera2.internal;
import android.content.Context;
import android.graphics.Point;
import android.hardware.display.DisplayManager;
import android.util.Size;
import android.view.Display;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RequiresApi;
import androidx.annotation.VisibleForTesting;
import androidx.camera.camera2.internal.compat.workaround.DisplaySizeCorrector;
import androidx.camera.camera2.internal.compat.workaround.MaxPreviewSize;
import androidx.camera.core.internal.utils.SizeUtil;
/**
* A singleton class to retrieve display related information.
*/
@RequiresApi(21) // TODO(b/200306659): Remove and replace with annotation on package-info.java
public class DisplayInfoManager {
private static final Size MAX_PREVIEW_SIZE = new Size(1920, 1080);
/**
* This is the smallest size from a device which had issue reported to CameraX.
*/
private static final Size ABNORMAL_DISPLAY_SIZE_THRESHOLD = new Size(320, 240);
/**
* The fallback display size for the case that the retrieved display size is abnormally small
* and no correct display size can be retrieved from DisplaySizeCorrector.
*/
private static final Size FALLBACK_DISPLAY_SIZE = new Size(640, 480);
private static final Object INSTANCE_LOCK = new Object();
private static volatile DisplayInfoManager sInstance;
@NonNull
private final DisplayManager mDisplayManager;
private volatile Size mPreviewSize = null;
private final MaxPreviewSize mMaxPreviewSize = new MaxPreviewSize();
private final DisplaySizeCorrector mDisplaySizeCorrector = new DisplaySizeCorrector();
private DisplayInfoManager(@NonNull Context context) {
mDisplayManager = (DisplayManager) context.getSystemService(Context.DISPLAY_SERVICE);
}
/**
* Gets the singleton instance of DisplayInfoManager.
*/
@NonNull
public static DisplayInfoManager getInstance(@NonNull Context context) {
if (sInstance == null) {
synchronized (INSTANCE_LOCK) {
if (sInstance == null) {
sInstance = new DisplayInfoManager(context);
}
}
}
return sInstance;
}
/**
* Test purpose only. To release the instance so that the test can create a new instance.
*/
@VisibleForTesting
static void releaseInstance() {
sInstance = null;
}
/**
* Update the preview size according to current display size.
*/
void refresh() {
mPreviewSize = calculatePreviewSize();
}
/**
* Retrieves the display which has the max size among all displays.
*
* @param skipStateOffDisplay true to skip the displays with off state
*/
@NonNull
public Display getMaxSizeDisplay(boolean skipStateOffDisplay) {
Display[] displays = mDisplayManager.getDisplays();
if (displays.length == 1) {
return displays[0];
}
// Try to find the max size display according to the skipStateOffDisplay parameter
Display maxDisplay = getMaxSizeDisplayInternal(displays, skipStateOffDisplay);
// Try to find the max size display from all displays again if no display can be found
// when only checking the non-state-off displays.
if (maxDisplay == null && skipStateOffDisplay) {
maxDisplay = getMaxSizeDisplayInternal(displays, false);
}
// If still no display found, throw IllegalArgumentException.
if (maxDisplay == null) {
throw new IllegalArgumentException("No display can be found from the input display "
+ "manager!");
}
return maxDisplay;
}
@Nullable
@SuppressWarnings("deprecation") /* getRealSize */
private Display getMaxSizeDisplayInternal(@NonNull Display[] displays,
boolean skipStateOffDisplay) {
Display maxDisplay = null;
int maxDisplaySize = -1;
for (Display display : displays) {
// Skips displays with state off if the input skipStateOffDisplay parameter is true
if (skipStateOffDisplay && display.getState() == Display.STATE_OFF) {
continue;
}
Point displaySize = new Point();
display.getRealSize(displaySize);
if (displaySize.x * displaySize.y > maxDisplaySize) {
maxDisplaySize = displaySize.x * displaySize.y;
maxDisplay = display;
}
}
return maxDisplay;
}
/**
* PREVIEW refers to the best size match to the device's screen resolution, or to 1080p
* (1920x1080), whichever is smaller.
*/
@NonNull
Size getPreviewSize() {
// Use cached value to speed up since this would be called multiple times.
if (mPreviewSize != null) {
return mPreviewSize;
}
mPreviewSize = calculatePreviewSize();
return mPreviewSize;
}
private Size calculatePreviewSize() {
Size displayViewSize = getCorrectedDisplaySize();
if (displayViewSize.getWidth() * displayViewSize.getHeight()
> MAX_PREVIEW_SIZE.getWidth() * MAX_PREVIEW_SIZE.getHeight()) {
displayViewSize = MAX_PREVIEW_SIZE;
}
return mMaxPreviewSize.getMaxPreviewResolution(displayViewSize);
}
@NonNull
@SuppressWarnings("deprecation") /* getRealSize */
private Size getCorrectedDisplaySize() {
Point displaySize = new Point();
// The PREVIEW size should be determined by the max display size among all displays on
// the device no matter its state is on or off. The PREVIEW size is used for the
// guaranteed configurations tables which are related to the camera's capability. The
// PREVIEW size should not be affected by the display state.
Display display = getMaxSizeDisplay(false);
display.getRealSize(displaySize);
Size displayViewSize = new Size(displaySize.x, displaySize.y);
// Checks whether the display size is abnormally small.
if (SizeUtil.isSmallerByArea(displayViewSize, ABNORMAL_DISPLAY_SIZE_THRESHOLD)) {
// Gets the display size from DisplaySizeCorrector if the display size retrieved from
// DisplayManager is abnormally small.
displayViewSize = mDisplaySizeCorrector.getDisplaySize();
// Falls back the display size to 640x480 if DisplaySizeCorrector doesn't contain the
// device's display size info.
if (displayViewSize == null) {
displayViewSize = FALLBACK_DISPLAY_SIZE;
}
}
// Flips the size to landscape orientation
if (displayViewSize.getHeight() > displayViewSize.getWidth()) {
displayViewSize = new Size(/* width= */ displayViewSize.getHeight(), /* height=
*/ displayViewSize.getWidth());
}
return displayViewSize;
}
}