Make it possible to record phone unlock screen

[borfast]

Describe the bug
When the phone screen is locked, it's very hard to enter the unlock code via the VNC viewer because it only shows a black screen.

I can press the buttons to enter the code by trial and error, so the input is still being transmitted to the phone, but the phone screen doesn't seem to be transmitted to the VNC client.

I'm not even sure if this is possible to fix, as it seems like a security feature of Android.

To Reproduce
Steps to reproduce the behavior:
Note: this assumes a phone that shows a lock screen with a code.

1. Lock the phone while connected to it using a vnc viewer.
2. Press the power button to show the unlock screen.
3. The screen is black and the buttons to enter the unlock code are not visible (though, as mentioned above, it is still possible to press them).

Expected Behavior
The phone unlock screen on the VNC viewer should be visible.

Logs/Backtraces
I don't think it's applicable but I can provide them if necesssary.

Your environment (please complete the following information):

• droidVNC-NG version: 2.4.0 (from F-Droid)
• Android version: 14 on a Pixel 7
• Client-side OS and version: Linux Mint 21.3
• VNC client and version: Remmina 1.4.25

Additional context
Not sure if this is relevant but I'll mention it in case someone thinks of something useful: I'm trying to help a friend who has ALS and cannot move, so he can control his phone from his computer (he controls the computer using an eye tracker).

[freebrowser1]

You probably need root for this. I think so.

[StatNoiz]

I've seen this behavior on Android 12 and up (Samsung Note 10/Tab S7+) but not on Android 10 and lower (Samsung Note 9/Note 8). On Android 10 and lower you can hit the "Home" button on your keyboard to bring up the lock screen.

That said, some apps have a black screen entirely which I'm pretty sure it related to the ability to screen capture which some apps block outright...most my banking apps and a few smart home apps prohibit screen grabs entirely and show a black screen during a VNC session.

[bk138]

I've seen this behavior on Android 12 and up (Samsung Note 10/Tab S7+) but not on Android 10 and lower (Samsung Note 9/Note 8). On Android 10 and lower you can hit the "Home" button on your keyboard to bring up the lock screen.

That could be, but I don't know for sure.

That said, some apps have a black screen entirely which I'm pretty sure it related to the ability to screen capture which some apps block outright...most my banking apps and a few smart home apps prohibit screen grabs entirely and show a black screen during a VNC session.

That's correct.

[StatNoiz]

I can confirm Samsung devices using Android 10 and lower will show lock screen and unlock pad. (Attaching redacted screenshots.)

Don't think I have anything with Android 11 but Android 12 is definitely a "no-go".