PointerEvent & DesktopSize in RFB protocol - c++

I have a problem I'm actually recoding the RFB protocol in my software to comunicate with a VNC Server, and I want to know how to get the size of the server Desktop Size.
I have allready test the framebuffer_width inside of the serverInit message but it is not representing the reel size of desktop I don't know how to get it ?
My second question is to send a PointerEvent message to the server.
To move the mouse, actually in my software I set the x and y of the mouse to position {0, 0}, when I send this to the VNC server it works successfully, but when I add 5 to the x position it doesn't move 5 pixel it move bigger than what I want, I don't understand why???? can you help me please ?
Thanks for your answers !

Sounds like both of your problems could be a scaling issue in your client.
Some questions that might help you answer your own question (since you really need to post more information if you want a definitive answer):
How are you determining that the real size of the desktop is not what is sent as the width in the serverInit message? Perhaps you are starting the VNC server and assuming that it is using the same size as the current desktop on the server and in fact it is starting with a different default size. With VNC servers on *nix systems, the VNC server generally runs as a separate desktop from the main desktop and the size isn't necessarily the same.
Are you certain that you are treating the serverInit width and the pointerEvent x and y position as 16-bit values?
Are you (advertising and) getting a DesktopSize pseudo-encoding after the ServerInit? It's possible the server may be changing the frame buffer size after you connect.
What language/framework/etc are you using to implement the client. Are you certain the rendering functions aren't being scaled somehow?
BTW, I've found the official RFB documentation to be somewhat lacking and I think these links are better for RFB reference:
http://tigervnc.sourceforge.net/cgi-bin/rfbproto
https://datatracker.ietf.org/doc/draft-levine-rfb/

Related

Set audio endpoint devices application specific (programmatically)

Link to the bug report on 'Feedback Hub'
An audio endpoint device, from here on referred to as 'endpoint', is a physical or virtual audio output or input device.
With the Windows 10 April Update 1803 the long overdue 'App volume and device preferences' have been introduced. These settings allow more control over audio stream management as it is now possible to set different endpoints for different applications, no matter whether that particular application comes with an endpoint selection or not.
However, there is an issue where the audio of a program, whose endpoint is non-default, is streamed through the default endpoint (or not at all) after it has been closed and launched again, although the endpoint is displayed correctly in the settings:
As far as I know the issue can be recreated on a Windows 10 machine (version 1803 or higher) with any virtual or physical endpoint and an affected program. I used 'VLC Media Player' in this example (disregarding the fact that it comes with an endpoint selection) as it is well known and widely accessible, which should make it easier to recreate the issue.
What I'm searching for...
... is a programmatically solution to switch between endpoints, which ideally can be launched in form of a script to set the correct endpoint with an application launch.
For my purpose it would be enough to have to adjust the device instance path manually, as the device would be always the same, but I'm not going to complain about a solution which retrieves the device instance path from the registry, too.
Defined endpoints and the device instance path of the device they are using can be retrieved from the subkeys of the key HKEY_USERS\# YOUR SID #\Software\Microsoft\Multimedia\Audio\DefaultEndpoint. I don't know how windows generates the name of the subkeys or where they can be found. If I had to take a wild guess, I'd say these are Application IDs (feel free to correct me if I'm wrong).
The device instance path itself can be found in the Device Manager (under 'Audio inputs and outputs' double click the desired device, navigate to the tab 'Details' and select 'Device instance path' from the 'Property' drop-down menu).
Additionally the entry about Audio Endpoint Devices and Stream Management in the Microsoft Docs might be helpful, but that is way above my head.
A possible but impractical workaround...
... would be, to manually set another endpoint for the application and switch back to desired endpoint at every launch of said application (as shown above).
But not just takes this at least 10 seconds at each and every launch, you might even forget to do this as the audio might just get streamed through the default endpoint *¹.
The alternative to the latter is, that no audio will be streamed at all *² or in some cases it actually works *³.
*¹ e.g.: VLC Media Player, Tom Clancy's Rainbow Six Siege (although the audio will be streamed correctly during the splash screens)
*² e.g.: Call of Duty 4: Modern Warfare, Call of Duty: Modern Warfare 2, Call of Duty: Modern Warfare 3
*³ e.g.: Window Media Player, Microsoft Edge, Firefox
Observations
VLC Media Player comes with an endpoint selection, but so does TeamSpeak 3 and, unlike VLC, it skips the Windows settings completely.
Call of Duty not streaming any audio most likely is connected to the engine as I didn't encounter any other application doing something similar.
Windows Media Player, Microsoft Edge and Firefox are the only programs (I tested so far) which work fine. They have no endpoint selection (I'd know of) and will use the correct endpoint after closing and launching it again. It should be noted, however, that Firefox and Microsoft Edge will show multiple instances in the "App volume and device preferences" when adjusting the endpoint.
Disclaimer
I already tried two 3rd party softwares: 'Audio Router', which didn't work at all and 'CheVolume', which doesn't solve the issue and constantly crashes while doing so.
This question is based on one I asked over at Super User (here), where I didn't get an answer I was able to work with due to my lack of knowledge regarding actual programming (I'm only somewhat familiar with Batch and PowerShell). I'm well aware that neither Stack Overflow nor Super User are script writing services, however, the issue is not being fixed with the Windows 10 October Update 1809 and I see this as a problem which is affecting not just me and with that would be helpful for multiple people after me. Feel free to write a comment or propose an edit if you see this differently.
I'm also not sure whether the tags 'audio-streaming' and 'endpoint' should be used in this context, please propose an edit if they shouldn't or you can think of any better.
Edit - 05/11/18
Using the 3rd party software 'EarTrumpet' I was able to overcome the issue with the 'Call of Duty' games (no audio at all after restarting), however, 'VLC Media Player' would not restart after I assigned a non-default endpoint with 'EarTrumpet' until I closed 'EarTrumpet' again and the issue with 'Tom Clancy's Rainbow Six Siege' remains the same.
Edit - 18/01/19
Added link to a bug report I created on the 'Feedback Hub' 2 month ago.
Edit - 20/01/19
After doing some testing again it should be noted that having 'EarTrumpet' run in the background will keep a non-default endpoint for 'VLC Media Player' across restarts, however, 'VLC Media Player' will only (reliably) restart when the non-default endpoint was set in the 'App volume and device preferences'.
I do not have any solution regarding a programming language to handle such events.
But I can recommend EarTrumpet app to handle this change more quickly https://www.theverge.com/2018/6/13/17457778/eartrumpet-windows-10-audio-app
(Windows store: https://www.microsoft.com/en-us/p/eartrumpet/9nblggh516xp?ranMID=24542&ranEAID=nOD%2FrLJHOac&ranSiteID=nOD_rLJHOac-hUn6PgKuMKwQLdrzRqnPTA&epi=nOD_rLJHOac-hUn6PgKuMKwQLdrzRqnPTA&irgwc=1&OCID=AID681541_aff_7593_1243925&tduid=%28ir__qwqlg6jd0jba3y9hpnbvikaite2xk6kuyv9udtr100%29%287593%29%281243925%29%28nOD_rLJHOac-hUn6PgKuMKwQLdrzRqnPTA%29%28%29&irclickid=_qwqlg6jd0jba3y9hpnbvikaite2xk6kuyv9udtr100&activetab=pivot:overviewtab )
I will update the answer if I find a easy way to script/program a change of output on each app.

Move Window Linux C

i'd like to make a function that can move a window in Linux in C++ by its PID. So I've tryed in under Windows. But I have trouble to compile it for Linux.
Is there any mean to do it with Qt ? Since I haven't found one, I've tryed to compile for Linux.
I'm using the MoveWindow function, which is part of the Windows API. Is there any Linux equivalent ?
You don't have to do that by hand if you don't really want to as there already are lots of tools out there, that can perform such tasks as moving, resizing, maximizing and whatever windows.
One tool you might want to take a closer look upon goes by the name of wmctrl even if you don't intend to use maybe you'll find some interesting tricks by taking a look into the sources.
The task of moving a window only known by the pid of the client that created the window might not be the easiest tasks of all for a couple of reasons.
First of all you really shouldn't try to do this as in the X Windows philosophy it is the job of the window manager to arrange the windows on the screen.
As well ICCCM (see: http://de.wikipedia.org/wiki/Inter-Client_Communication_Conventions_Manual) as the EWM spec (see: http://standards.freedesktop.org/wm-spec/wm-spec-latest.html) strongly discourage any client from trying to move resize or whatever on its own. Most probably moving windows "owned" by another client might be considered even bigger evil.
The second problem you might face is, that the X 11 protocol doesn't have any notion of pid.
As it was designed to be used over a network you never can't be really sure the program runs on the same machine as the one you are currently sitting in front of. As such there isn't much sense in something like a pid as by chance there might be any number of clients with identical pids displaying windows on the same X Server if they ran on different machines.
Fortunately enough it is not all that bad, as the EWMH spec encourages any client to set the _NET_WM_PID property on its top level window the the pid of the client that created the window.
Again adhering to the EWMH spec isn't enforced by the X Server in any way so that while practically propably almost all clients will set it there's still no guarantee you'll find the window belonging to a specific pid.
Possibilities
While the whole points mentioned until here might seem rather limiting in fact most probably rather the opposite is true. Even because practically it is relatively easy to totally mess up any other client running in an X session the whole set of rules about how to be a good citizen in the X word were introduced.
As the X11 protocol itself is a network protocol (well not 100% true as locally running clients most probably will be communicating with the X Server via a UNIX domain socket) there isn't any specific library required to talk to the X Server.
Talking about C as mentioned in your question the Xlib has long been the one and only one implementation in wide use but there's also another binding called xcb. With a slightly changed API in comparison to the Xlib.
Xlib
Speaking Xlib I've never ever used any xcb until now, so I can't tell you too much about it might be the following methods that might be of use.
XOpenDisplay - open connection to the X server
XQueryTree - aquire the tree of windows currently alive on the server
XInternAtom - no fear it isn't dangerous. Just read about it in the manuals as you'll need it the get the "atom" mapping to _NET_WM_PID mentioned above
XListProperties - search for the _NET_WM_PID property with the value you are looking for
XConfigureWindow, XMoveWindow, XResizeWindow, ... - to finally perform whatever you wish to do.
All functions mentioned above should be documented in the manual pages. Just use man XOpenDisplay for example.
Oh, and be sure to learn about all the other tools at your disposal to further investigate about the X Window world. Run xlsatoms, check what xwininfo reports an take a list at the output of xprop for one single (!) window alone. Try to set some yourself to see what happens xprop will even do that for you if you ask politely.

OpenGL and MultiGPU

We are trying to setup a server with Multiple Tesla M2050 to run with OpenGL.
The current setup is as follows : Ubuntu 12.04 with NVidia Drivers. We have setup the xorg.conf with separate devices identified by BUS ID.
Now we have tied an X server each with display which in turn is tied to each device and our code is attached to each of these X servers. But somehow only one X session seems to work out alright. The other one produces garbled output and while watching it from nvidia-smi, we notice that when the garbled output is being produced the GPU's are not at all used.
Could someone verify that our setup seems reasonable? The other thing we noticed was that, it was only the first X server that was started is the one that has the issue.
EDIT : This is in headless mode.
A problem with multiple X servers is, that each server may grab the active VT and hence disable the other X server's rendering output. This can be avoided. But I think in your situation good ole' "Zaphod Mode" would suit your needs far better:
Zaphod mode is a single X server, controlling multiple Devices, each with its own Monitor forming a Screen, joined in a single screen layout. This is not TwinView or Xinerama! In Zaphod mode you can not move windows between Screens, i.e. each Screen acts on its own.

Windows Mobile C++ - Application design-type question

i have my application skeleton working as expected - it might be that somebody has a good solution to what i am trying to achieve within Windows Mobile 6.5 enviroment.
Here's what i am actually trying to do:
Application running in background ( it sends periodically network packets to office server, packets are loaded with statistics data and pushed onto the server via Winsock2 and custom made protocol ).
What 'background' means here - is an application that creates a window of 0,0 size and is minimized - i am thinking about going into the services with this, but the next thing that i require stops me today from doing this.
I need this application to be 'visible' somewhere as an icon - i already know i can't do this in the 'tray' area as stated in this post:
Windows Mobile C++ Tray Icon
Now i was trying to utilize the: SHNotificationAdd - but this is ok for a 'notification' as the name says type of thing. So it popsup and you can click to hide it - this is bad.
What i need to achieve is an icon that is visible during the application run cycle, so it flashes when there is no synchronization possible, it changes the icon when synchronization is done.
I am a bit worried it can't be done - i even tried to go and code the "Home" plug-in for this purpose, but was told that some people have themes installed and it might be that my application won't be even visible to those guys.
Now as we're going to deploy it to few places around ( 3 data centers spread across the country - around 130 people smart phones only ) - i need to be sure this application is visible even when there is a theme applied or customization done.
Any chance this can be done ?
I was kinda sure it can be done with a classic 'tray icon approach' until i found that 'tray icons' are not supported for normal applications.
If there is something i can do - i would really appreciate if somebody could shed a bit of light on this for us all please.
You'll have to move to a Windows Mobile paradigm for your app, as what you're trying to do isn't possible (as you're finding). A home screen plug in has problems if the user customizes it, and you are correct that there is no "tray". The icons in the corner (battery, signal strength, etc) are reserved for OEM use only.
My recommendation would be to actually create a visible Form for your application. Maybe it shows just some simple status info like last upload time, amount of data transferred, etc.
You then use the notifications to place a user notification during "events" such as the inability to connect (replacing your "flashing icon" idea) or when synchronization is complete (replacing your "changed icon" idea).

Volume Control Number of Channels XP different than Vista

When I run this code:
MIXERLINE MixerLine;
memset( &MixerLine, 0, sizeof(MIXERLINE) );
MixerLine.cbStruct = sizeof(MIXERLINE);
MixerLine.dwComponentType = MIXERLINE_COMPONENTTYPE_SRC_WAVEOUT;
mmResult = mixerGetLineInfo( (HMIXEROBJ)m_dwMixerHandle, &MixerLine, MIXER_GETLINEINFOF_COMPONENTTYPE );
Under XP MixerLine.cChannels comes back as the number of channels that the sound card supports. Often 2, these days often many more.
Under Vista MixerLine.cChannels comes back as one.
I have been then getting a MIXERCONTROL_CONTROLTYPE_VOLUME control and setting the volume for each channel that is supported, and setting the volumne control to different levels on different channels so as to pan music back and forth between the speakers (left to right).
Obviously under Vista this approach isn't working since there is only one channel. I can set the volume and it is for both channels at the same time.
I tried to get a MIXERCONTROL_CONTROLTYPE_PAN for this device, but that was not a valid control.
So, the question for all you MMSystem experts is this: what type of control do I need to get to adjust the left/right balance? Alternately, is there a better way? I would like a solution that works with both XP and Vista.
Computer Details: Running Vista Ultimta 32 bit SP1 and all latest patches. Audio is provided by a Creative Audigy 2 ZS card with 4 speakers attached which can all be properly addressed (controlled) through Vista's sound panel. Driver is latest on Creative's site (SBAX_PCDRV_LB_2_18_0001). The Vista sound is not set to mono, and all channels are visable and controlable from the sound panel.
Running the program in "XP Compatibility Mode" does not change the behaviour of this problem.
If you run your application in "XP compatibility" mode, the mixer APIs should work much closer to the way they did in XP.
If you're not running in XP mode, then the mixer APIs reflect the mix format - if your PC's audio solution is configured for mono, then you'll see only one channel, but if you're machine is configured for multichannel output the mixer APIs should reflect that.
You can run the speaker tuning wizard to determine the # of channels configured for your audio solution.
Long time Microsoftie Larry Osterman has a blog where he discusses issues like this because he was on the team that redid all the audio stuff in Vista.
In the comments to this blog post he seems to indicate that application controlled balance is not something they see the need for:
CN, actually we're not aware of ANY situations in which it's appropriate for an application to control its balance. Having said that, we do support individual channel volumes for applications, but it is STRONGLY recommended that apps don't use it.
He also indicates that panning the sound from one side to the other can be done, but it is dependent on whether the hardware supports it:
Joku, we're exposing the volume controls that the audio solution implements. If it can do pan, we do pan (we actually expose separate sliders for the left and right channels).
So that explains why the MIXERCONTROL_CONTROLTYPE_PAN thing failed -- the audio hardware on your system does not support it.