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Listen to display changed events
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Replace RotationWatcher and DisplayFoldListener by a single
DisplayListener, which is notified whenever the display size or dpi
changes.

Still use the old mechanism specifically for Android 14, where
DisplayListener may be broken (it is fixed in recent Android 14
upgrades), until we receive the first DisplayListener event (which
proves that it works).

Fixes #161 <#161>
Fixes #1918 <#1918>
Fixes #4152 <#4152>
Refs #4469 <#4469>

Co-authored-by: Simon Chan <[email protected]>
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@rom1v @yume-chan
rom1v and yume-chan committed Oct 28, 2024
1 parent a42a0ad commit f92dfa6
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Showing 3 changed files with 195 additions and 33 deletions.
2 changes: 1 addition & 1 deletion server/src/main/java/com/genymobile/scrcpy/device/Size.java
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,6 @@ public int hashCode() {

@Override
public String toString() {
return "Size{" + "width=" + width + ", height=" + height + '}';
return "Size{" + width + 'x' + height + '}';
}
}
157 changes: 125 additions & 32 deletions server/src/main/java/com/genymobile/scrcpy/video/ScreenCapture.java
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Original file line number Diff line number Diff line change
Expand Up @@ -7,12 +7,15 @@
import com.genymobile.scrcpy.device.Size;
import com.genymobile.scrcpy.util.Ln;
import com.genymobile.scrcpy.util.LogUtils;
import com.genymobile.scrcpy.wrappers.DisplayManager;
import com.genymobile.scrcpy.wrappers.ServiceManager;
import com.genymobile.scrcpy.wrappers.SurfaceControl;

import android.graphics.Rect;
import android.hardware.display.VirtualDisplay;
import android.os.Build;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.IBinder;
import android.view.IDisplayFoldListener;
import android.view.IRotationWatcher;
Expand All @@ -29,9 +32,18 @@ public class ScreenCapture extends SurfaceCapture {
private DisplayInfo displayInfo;
private ScreenInfo screenInfo;

private Size sessionSize;

private IBinder display;
private VirtualDisplay virtualDisplay;

private DisplayManager.DisplayListenerHandle displayListenerHandle;
private HandlerThread handlerThread;

// On Android 14, the DisplayListener may be broken (it never send events). This is fixed in recent Android 14 upgrades, but we can't really know.
// So register a RotationWatcher and a DisplayFoldListener as a fallback, until we receive the first event from DisplayListener (which proves
// that it works).
private boolean displayListenerWorks; // only accessed from the display listener thread
private IRotationWatcher rotationWatcher;
private IDisplayFoldListener displayFoldListener;

Expand All @@ -45,39 +57,57 @@ public ScreenCapture(VirtualDisplayListener vdListener, int displayId, int maxSi

@Override
public void init() {
if (displayId == 0) {
rotationWatcher = new IRotationWatcher.Stub() {
@Override
public void onRotationChanged(int rotation) {
requestReset();
}
};
ServiceManager.getWindowManager().registerRotationWatcher(rotationWatcher, displayId);
if (Build.VERSION.SDK_INT == AndroidVersions.API_34_ANDROID_14) {
registerDisplayListenerFallbacks();
}

if (Build.VERSION.SDK_INT >= AndroidVersions.API_29_ANDROID_10) {
displayFoldListener = new IDisplayFoldListener.Stub() {

private boolean first = true;

@Override
public void onDisplayFoldChanged(int displayId, boolean folded) {
if (first) {
// An event is posted on registration to signal the initial state. Ignore it to avoid restarting encoding.
first = false;
return;
handlerThread = new HandlerThread("DisplayListener");
handlerThread.start();
Handler handler = new Handler(handlerThread.getLooper());
displayListenerHandle = ServiceManager.getDisplayManager().registerDisplayListener(displayId -> {
if (Ln.isEnabled(Ln.Level.VERBOSE)) {
Ln.v("ScreenCapture: onDisplayChanged(" + displayId + ")");
}
if (Build.VERSION.SDK_INT == AndroidVersions.API_34_ANDROID_14) {
if (!displayListenerWorks) {
// On the first display listener event, we know it works, we can unregister the fallbacks
displayListenerWorks = true;
unregisterDisplayListenerFallbacks();
}
}
if (this.displayId == displayId) {
DisplayInfo di = ServiceManager.getDisplayManager().getDisplayInfo(displayId);
if (di == null) {
Ln.w("DisplayInfo for " + displayId + " cannot be retrieved");
// We can't compare with the current size, so reset unconditionally
if (Ln.isEnabled(Ln.Level.VERBOSE)) {
Ln.v("ScreenCapture: requestReset(): " + getSessionSize() + " -> (unknown)");
}
setSessionSize(null);
requestReset();
} else {
Size size = di.getSize();

if (ScreenCapture.this.displayId != displayId) {
// Ignore events related to other display ids
return;
}
// The field is hidden on purpose, to read it with synchronization
@SuppressWarnings("checkstyle:HiddenField")
Size sessionSize = getSessionSize(); // synchronized

requestReset();
// .equals() also works if currentSize == null
if (!size.equals(sessionSize)) {
// Reset only if the size is different
if (Ln.isEnabled(Ln.Level.VERBOSE)) {
Ln.v("ScreenCapture: requestReset(): " + sessionSize + " -> " + size);
}
// Set the new size immediately, so that a future onDisplayChanged() event called before the asynchronous prepare()
// considers that the current size is the requested size (to avoid a duplicate requestReset())
setSessionSize(size);
requestReset();
} else if (Ln.isEnabled(Ln.Level.VERBOSE)) {
Ln.v("ScreenCapture: Size not changed (" + size + "): do not requestReset()");
}
}
};
ServiceManager.getWindowManager().registerDisplayFoldListener(displayFoldListener);
}
}
}, handler);
}

@Override
Expand All @@ -93,6 +123,7 @@ public void prepare() throws ConfigurationException {
}

screenInfo = ScreenInfo.computeScreenInfo(displayInfo.getRotation(), displayInfo.getSize(), crop, maxSize, lockVideoOrientation);
setSessionSize(screenInfo.getVideoSize());
}

@Override
Expand Down Expand Up @@ -146,12 +177,11 @@ public void start(Surface surface) {

@Override
public void release() {
if (rotationWatcher != null) {
ServiceManager.getWindowManager().unregisterRotationWatcher(rotationWatcher);
}
if (Build.VERSION.SDK_INT >= AndroidVersions.API_29_ANDROID_10) {
ServiceManager.getWindowManager().unregisterDisplayFoldListener(displayFoldListener);
if (Build.VERSION.SDK_INT == AndroidVersions.API_34_ANDROID_14) {
unregisterDisplayListenerFallbacks();
}
handlerThread.quitSafely();
ServiceManager.getDisplayManager().unregisterDisplayListener(displayListenerHandle);
if (display != null) {
SurfaceControl.destroyDisplay(display);
display = null;
Expand Down Expand Up @@ -191,4 +221,67 @@ private static void setDisplaySurface(IBinder display, Surface surface, int orie
SurfaceControl.closeTransaction();
}
}

private synchronized Size getSessionSize() {
return sessionSize;
}

private synchronized void setSessionSize(Size sessionSize) {
this.sessionSize = sessionSize;
}

private void registerDisplayListenerFallbacks() {
if (displayId == 0) {
rotationWatcher = new IRotationWatcher.Stub() {
@Override
public void onRotationChanged(int rotation) {
if (Ln.isEnabled(Ln.Level.VERBOSE)) {
Ln.v("ScreenCapture: onRotationChanged(" + rotation + ")");
}
requestReset();
}
};
ServiceManager.getWindowManager().registerRotationWatcher(rotationWatcher, displayId);
}

// Build.VERSION.SDK_INT >= AndroidVersions.API_29_ANDROID_10 (but implied by == API_34_ANDROID 14)
displayFoldListener = new IDisplayFoldListener.Stub() {

private boolean first = true;

@Override
public void onDisplayFoldChanged(int displayId, boolean folded) {
if (first) {
// An event is posted on registration to signal the initial state. Ignore it to avoid restarting encoding.
first = false;
return;
}

if (Ln.isEnabled(Ln.Level.VERBOSE)) {
Ln.v("ScreenCapture: onDisplayFoldChanged(" + displayId + ", " + folded + ")");
}

if (ScreenCapture.this.displayId != displayId) {
// Ignore events related to other display ids
return;
}
requestReset();
}
};
ServiceManager.getWindowManager().registerDisplayFoldListener(displayFoldListener);
}

private void unregisterDisplayListenerFallbacks() {
synchronized (this) {
if (rotationWatcher != null) {
ServiceManager.getWindowManager().unregisterRotationWatcher(rotationWatcher);
rotationWatcher = null;
}
if (displayFoldListener != null) {
// Build.VERSION.SDK_INT >= AndroidVersions.API_29_ANDROID_10 (but implied by == API_34_ANDROID 14)
ServiceManager.getWindowManager().unregisterDisplayFoldListener(displayFoldListener);
displayFoldListener = null;
}
}
}
}
69 changes: 69 additions & 0 deletions server/src/main/java/com/genymobile/scrcpy/wrappers/DisplayManager.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -9,17 +9,40 @@
import android.annotation.SuppressLint;
import android.content.Context;
import android.hardware.display.VirtualDisplay;
import android.os.Handler;
import android.view.Display;
import android.view.Surface;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

@SuppressLint("PrivateApi,DiscouragedPrivateApi")
public final class DisplayManager {

// android.hardware.display.DisplayManager.EVENT_FLAG_DISPLAY_CHANGED
public static final long EVENT_FLAG_DISPLAY_CHANGED = 1L << 2;

public interface DisplayListener {
/**
* Called whenever the properties of a logical {@link android.view.Display},
* such as size and density, have changed.
*
* @param displayId The id of the logical display that changed.
*/
void onDisplayChanged(int displayId);
}

public static final class DisplayListenerHandle {
private final Object displayListenerProxy;
private DisplayListenerHandle(Object displayListenerProxy) {
this.displayListenerProxy = displayListenerProxy;
}
}

private final Object manager; // instance of hidden class android.hardware.display.DisplayManagerGlobal
private Method createVirtualDisplayMethod;

Expand Down Expand Up @@ -137,4 +160,50 @@ public VirtualDisplay createNewVirtualDisplay(String name, int width, int height
android.hardware.display.DisplayManager dm = ctor.newInstance(FakeContext.get());
return dm.createVirtualDisplay(name, width, height, dpi, surface, flags);
}

public DisplayListenerHandle registerDisplayListener(DisplayListener listener, Handler handler) {
try {
Class<?> displayListenerClass = Class.forName("android.hardware.display.DisplayManager$DisplayListener");
Object displayListenerProxy = Proxy.newProxyInstance(
ClassLoader.getSystemClassLoader(),
new Class[] {displayListenerClass},
(proxy, method, args) -> {
if ("onDisplayChanged".equals(method.getName())) {
listener.onDisplayChanged((int) args[0]);
}
return null;
});
try {
manager.getClass()
.getMethod("registerDisplayListener", displayListenerClass, Handler.class, long.class, String.class)
.invoke(manager, displayListenerProxy, handler, EVENT_FLAG_DISPLAY_CHANGED, FakeContext.PACKAGE_NAME);
} catch (NoSuchMethodException e) {
try {
manager.getClass()
.getMethod("registerDisplayListener", displayListenerClass, Handler.class, long.class)
.invoke(manager, displayListenerProxy, handler, EVENT_FLAG_DISPLAY_CHANGED);
} catch (NoSuchMethodException e2) {
manager.getClass()
.getMethod("registerDisplayListener", displayListenerClass, Handler.class)
.invoke(manager, displayListenerProxy, handler);
}
}

return new DisplayListenerHandle(displayListenerProxy);
} catch (Exception e) {
// Rotation and screen size won't be updated, not a fatal error
Ln.e("Could not register display listener", e);
}

return null;
}

public void unregisterDisplayListener(DisplayListenerHandle listener) {
try {
Class<?> displayListenerClass = Class.forName("android.hardware.display.DisplayManager$DisplayListener");
manager.getClass().getMethod("unregisterDisplayListener", displayListenerClass).invoke(manager, listener.displayListenerProxy);
} catch (Exception e) {
Ln.e("Could not unregister display listener", e);
}
}
}

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