Screen Blanking Image

[dkaine]

There should be a method of changing/customizing the image displayed on the screen when you blank it and disable the keyboard and mouse... The uVNC icon, while ubiquitous in the IT community, is actually quite creepy to the General End User Public. "There's a giant eyeball on my screen, I think I've been hacked/gotten a virus!" or even better, they power the machine down in a panic!

[B]

I think workarounds are documented in the forums somewhere.

[supercoe]

Keep in mind I've never tested this, please report back if it works.

http://www.uvnc.com/docs/uvnc-server/69 ... ncini.html

BlackAlphaBlending=0
Instead of using the powermanager to blank the monitor we put a layered window on top and capture the windows below. Using this option you also can define a custom blank by placing a file "background.bmp" in the ultravnc folder.

[Bonji]

Does this method allow you to show a custom image on the VNC server while still effectively remote controlling it via the VNC viewer?

I think I tried this before but my viewer only ever showed the custom image instead of what was under it.

[B]

For what it's worth, iTalc ( http://italc.sourceforge.net/home.php ) has had that feature for a long time. I think they use TightVNC though.

[supercoe]

Just did a quick test.
UltraVNC 1.0.9.6.1
Default ini settings.
Putting a bitmap image named "background.bmp" in the same folder as winvnc.exe showed the image stretched to fill the whole screen.

Tested with 256 color and 24bit bitmap images on Vista 64bit.

[B]

But it shows on both the server console and the remote viewer?

[supercoe]

Sorry, missed that part.

Mine would only show the background.bmp correctly on the UltraVNC Server side.
The viewer displayed what was behind the blanking image as expected.

Side note, if you change the background.bmp file you have to restart the UltraVNC Server.

[B]

Well that's good to know. I didn't think it would still work. Still, you can never really bet on this kind of feature working. When using LogMeIn I'll get warnings when it doesn't think it can blank the screen. Who knows, unless you've got a webcam pointed at the screen.

[Bonji]

I tried working with the screen blanking image again, but everytime I blank the screen the background.bmp image shows on the client and the server making it impossible for me to do anything with the remote client. Both computers are Win7 SP1 running VNC 1.0.9.6.1. I'm also using the SecureVNC encryption plugin plus NewMSLogon authentication.

I tried every possible combination of the following two settings:

BlackAlphaBlending=0, CaptureAlphaBlending=0
BlackAlphaBlending=0, CaptureAlphaBlending=1
BlackAlphaBlending=1, CaptureAlphaBlending=0
BlackAlphaBlending=1, CaptureAlphaBlending=1

Also, these settings were configured as follows:

BlankInputsOnly=0
BlankMonitorEnabled=1

Am I missing something in the configuration?

[supercoe]

Not sure what is going on here...

I just tested again:

UltraVNC Server 1.0.9.6.1 on Win7 64bit

ultravnc.ini:

Code: Select all

[Permissions]
[admin]
FileTransferEnabled=1
FTUserImpersonation=1
BlankMonitorEnabled=1
BlankInputsOnly=0
CaptureAlphaBlending=0
BlackAlphaBlending=0
DefaultScale=1
UseDSMPlugin=1
DSMPlugin=SecureVNCPlugin.dsm
DSMPluginConfig=SecureVNC;0;0x00104001;cGFzc3dvcmQ=
primary=1
secondary=0
SocketConnect=1
HTTPConnect=1
XDMCPConnect=0
AutoPortSelect=1
InputsEnabled=1
LocalInputsDisabled=0
IdleTimeout=0
EnableJapInput=0
QuerySetting=2
QueryTimeout=10
QueryAccept=0
LockSetting=0
RemoveWallpaper=1
RemoveEffects=0
RemoveFontSmoothing=0
RemoveAero=1
DebugMode=0
Avilog=0
path=C:\Users\ThaChunk\Desktop\UltraVNC
DebugLevel=0
AllowLoopback=0
LoopbackOnly=0
AllowShutdown=1
AllowProperties=1
AllowEditClients=1
FileTransferTimeout=30
KeepAliveInterval=5
SocketKeepAliveTimeout=10000
DisableTrayIcon=0
MSLogonRequired=0
NewMSLogon=0
ConnectPriority=0
[ultravnc]
passwd=DBD83CFD727A145844
passwd2=8BF749ADC043135FED

Everything works as it should, custom background.bmp file is displayed correctly whether or not I'm using the SecureVNC plugin.

The only thing to note here is that UAC was turned down all the way on this machine.

[B]

I think it's also a video driver and memory caching phenomenon; that's why I said you can't rely on it.