How to take a screenshot in WP8? - windows-phone-8

How to produce a complete WP8 screenshot? By “complete” I mean “including application bar, status bar, message boxes and keyboard”.
Things I’ve tried:
GDI API that worked in WP7 (GetDC, CreateCompatibleDC, BitBlt), result - CreateCompatibleDC or CreateDCW return NULL, GetLastError says “the specified procedure could not be found”. Moreover, it seems WP8 only has the single HDC, namely 0x00dc00dc, so no off-screen GDI DCs are possible.
InvokeScreenCapture and SaveApplicationScreenShot from ShellChrome.dll – application deactivates, nothing else happens.
D3D11Device1::GetImmediateContext, ID3D11RenderTargetView::OMGetRenderTargets – OMGetRenderTargets returns NULL.
Any other ideas?
I don’t need to pass marketplace certification, so unsupported/undocumented APIs are OK.

In WP8 and under there is no way to capture the entire screen without running in TCB (requires a hacked image) and loading in libs that don't ship with any SDK.

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Has anyone reversed engineered the protocol used by Apple's iOS Remote app for controlling an Apple TV over IP?

I'm curious if it's possible for me to write programs that can control an Apple TV, specifically an Apple TV 4th gen running tvOS 9.1.1, like Apple's Remote app for iOS can. I'd like to send it commands for navigating in the four cardinal directions, selecting an item on the screen, going up the navigation stack -- essentially what Apple's Remote app can do.
Has anyone done any work reverse engineering the protocol it uses? Cursory Googling only has so far yielded out of date results about earlier generation Apple TVs and the DAAP protocol which looks like something different than what I want.
I captured the traffic on my iPhone using tcpdump and analyzed it with WireShark. The Remote app asks the Apple TV with normal HTTP requests on port 3689.
The workflow of the app consists in four HTTP requests:
/server-info for getting infos about the Apple TV. It responds with a Apple proprietary DAAP response (Digital Audio Access Protocol) providing some tags about the device, like the display name.
/login is performed during connection, when the app displays the "Connecting to Apple TV..." message. It responds with a DAAP about the login status.
Here's the bottleneck. /home-share-verify validates the connection between the app and the Apple TV. This call needs a Client-DAAP-Validation header with a long unknown string value. According to Wikipedia, this seems to be like an hash generated by a certificate exchange between verified sources that was introduced in iTunes 7.0+ and never reverse engineered.
/ctrl-int/1/{controlpromptupdate|controlpromptentry|playstatusupdate} seems to be the calls made for the input buttons.
Some other minor calls are fired in between (like a Bonjour service update or a /databases call).
Here and here you can find more infos. Hope this helps for getting an overview of how this simple (but protected) app works.
i wanted to tell alexa to trigger appletv and that would wake my appletv up and via HDMI & CEC turn my tv on,
in order to do that:
from your mac\linux\windows simply run:
curl -XPOST -d 'cmcc\x00\x00\x00\x01\x30cmbe\x00\x00\x00\x04menu' 'http://10.1.1.56:3689/ctrl-int/1/controlpromptentry?prompt-id=144&session-id=1'
the abstract command is:
curl -XPOST -d 'cmcc\x00\x00\x00\x01\x30cmbe\x00\x00\x00\x04menu' 'http://{APPLETV_IP}:3689/ctrl-int/1/controlpromptentry?prompt-id={CONTROL_PAIR_ID}&session-id={CONTROL_SESSION_ID}'
i extracted the CONTROL_PAIR_ID and CONTROL_SESSION_ID by setting my iphone wifi http proxy settings to my mac with fiddler on it and activated the old appletv remote app and that displayed the requests the app is executing
if you don't know how to set iphone to work with fiddler you can find it here:
http://docs.telerik.com/fiddler/Configure-Fiddler/Tasks/ConfigureForiOS
I did manage to control my Apple TV (currently running tvOS 9.2) from a python script. It turns out that you don't need to use Home Sharing to have a remote app control the Apple TV. I don't know if the following method will work if Home Sharing is enabled, but with it disabled on the Apple TV, the iOS Remote app has the option to manually add a device. (This may require removing all of the devices it is already paired with, since that was unfortunately necessary for me to get it to display the 'Add a device' button.) Once I had paired my iPhone to the Apple TV, I recorded some of its requests, copied the pairing GUID, and then constructed some of my own requests.
The only three requests necessary to make are:
/login?pairing-guid=< your pairing guid here >&hasFP=1
Logs into the Apple TV. The last four bytes of the response's is a session id, encoded as a big-endian four byte integer.
/logout?session-id=< your session id here >
Logs out. Not strictly necessary, as I found that logging in simply gets you a new session id, but probably not a bad idea to do things the way it expects.
/ctrl-int/1/controlpromptentry?prompt-id=114&session-id=< your session id here >
Send user input to the Apple TV. The data is one of several buffers that input a command, or possible a moving touch. For movement in the cardinal directions, sending several of these requests to simulate a moving touch is necessary.
I have a python script demonstrating how to do this here:
http://pastebin.com/mDHc353A
Utilizes the requests library: http://docs.python-requests.org/en/master/
Also special thanks to Adam Miskiewicz / github user skevy, since I made use of this file in his atlas-backend repo that conveniently had the right buffers to send for movement: https://github.com/skevy/atlas-backend/blob/master/atlas/services/appletv.coffee
For any people still checking out this question, I recommend checking out pyatv if they want to control their Apple TV through a python or command line interface.

GoogleWebAuthorizationBroker sometimes crashes the app

I have a Windows Phone 8.1 app with Google login, which uses the
GoogleWebAuthorizationBroker.AuthorizeAsync
method. 90 % of the time, the authentication works, however, occasionally, the app just crashes on this line (I am logging right before it, so I am sure). I have the call wrapped inside try - catch, but that doesn't seem to work - exception is never caught.
I am also sure I am calling the method on a UI thread, I am using the DispatcherHelper from MVVMLight for that.
The fact that I am not able to reproduce the crash complicates this a lot, I have not experienced it with debugger attached, only in Release mode, on target device, run locally.
Do you guys have any ideas / clues / pointers? I know I'm not providing a lot of information, but I don't have any..
EDIT> So the error now happened with debugger attached - and the app just froze, last message in Ouput window was
"WinRT information: Cannot get credential from Vault"
But that's normal behavior..

Is it possible to use the cast API from a chome app? how to bypass the receiver selection popup?

Does anyone know, is the cast API supported for use from a chrome app? It initializes fine, says there are receivers available but I can't get a session - when I call requestSession nothing happens at all, neither success nor error callbacks are called, no window is displayed.
Maybe I'm approaching this all wrong...what I'm trying to do seems like it should be relatively straight-forward, but it really seems like google has deliberately prevented this. All I'm trying to do is hook my IR remote up to my chromecast for media playback controls (play/pause/seek). Even if the requestSession method worked, it really wouldn't give the user experience I want - it would still require the user to select the receiver from the popupmenu UI whenever they want to use their IR remote - far from friendly. Instead I'd like to be able to pre-configure which chromecast the IR remote is bound to...and then it would always just connect to whatever app/session is currently running on that receiver to issue play/pause/seek commands.
I could implement this as a browser extension instead, and I'm sure I could get it functional that way...but that would be even less user-friendly (not to mention I'm already using some app-only APIs for the IR-receiving side of it which would have to be re-worked to other methods).
edit: Ok, after a bit more looking I've found this which I guess mostly answers my question https://code.google.com/p/chromium/issues/detail?id=287254 ....but the question about the popup still stands...even if using an extension is there any way to bypass the reciever-selection popup that requires user interaction?

Captured audio buffers are all silent on Windows Phone 8

I'm trying to capture audio using WASAPI. My code is largely based on the ChatterBox VoIP sample app. I'm getting audio buffers, but they are all silent (flagged AUDCLNT_BUFFERFLAGS_SILENT).
I'm using Visual Studio Express 2012 for Windows Phone. Running on the emulator.
I had the exact same problem and managed to reproduce it in the ChatterBox sample app if I set Visual Studio to native debugging and at any point stepped through the code.
Also, closing the App without going through the "Stop" procedure and stopping the AudioClient will require you to restart the emulator/device before being able to capture audio data again.
It nearly drove me nuts before I figured out the before mentioned problems but I finally got it working.
So..
1. Be sure to NOT do native debugging
2. Always call IAudioClient->Stop(); before terminating the App.
3. Make sure you pass the correct parameters to IAudioClient->Initialize();
I've included a piece of code that works 100% of the time for me. I've left out error checking for clarity..
LPCWSTR pwstrDefaultCaptureDeviceId =
GetDefaultAudioCaptureId(AudioDeviceRole::Communications);
HRESULT hr = ActivateAudioInterface(pwstrDefaultCaptureDeviceId,
__uuidof(IAudioClient2), (void**)&m_pAudioClient);
hr = m_pAudioClient->GetMixFormat(&m_pwfx);
m_frameSizeInBytes = (m_pwfx->wBitsPerSample / 8) * m_pwfx->nChannels;
hr = m_pAudioClient->Initialize(AUDCLNT_SHAREMODE_SHARED,
AUDCLNT_STREAMFLAGS_NOPERSIST | AUDCLNT_STREAMFLAGS_EVENTCALLBACK,
latency * 10000, 0, m_pwfx, NULL);
hr = m_pAudioClient->SetEventHandle(m_hCaptureEvent);
hr = m_pAudioClient->GetService(__uuidof(IAudioCaptureClient),
(void**)&m_pCaptureClient);
And that's it.. Before calling this code I've started a worker thread that will listen to m_hCaptureEvent and call IAudioCaptureClient->GetBuffer(); whenever the capture event is triggered.
Of course using Microsoft.XNA.Audio.Microphone works fine to, but it's not always an option to reference the XNA framework.. :)
It was a really annoying problem which waste about 2 complete days of mine.My problem was solved by setting AudioClientProperties.eCatagory to AudioCategory_Communications instead of AudioCategory_Other.
After this long try and error period I am not sure that the problem won't repeat in the future because the API doesn't act very stable and every run may return a different result.
Edit:Yeah my guess was true.Restarting the wp emulator makes the buffer silent again.But changing the AudioClientProperties.eCatagory back to AudioCategory_Other again solve it.I still don't know what is wrong with it and what is the final solution.
Again I encounter the same problem and this time commenting (removing) the
properties.eCategory = AudioCategory_Communications;
solve the problem.
I can add my piece of advice for Windows Phone 8.1.
I made the following experiment.
Open capture device. Buffers are not silent.
Open render device with AudioDeviceRole::Communications. Buffers immediately go silent.
Close render device. Buffers are not silent.
Then I opened capture device with AudioDeviceRole::Communications and capture device works fine all the time.
For Windows 10 capture device works all the time, no matter if you open it with AudioDeviceRole::Communications or not.
I've had the same problem. It seems like you can either use only AudioCategory_Other or create an instance of VoipPhoneCall and use only AudioCategory_Communications.
So the solution in my case was to use AudioCategory_Communications and create an outgoing VoipPhoneCall. You should implement the background agents as in Chatterbox VoIP sample app for the VoipCallCoordinator to work .

Is it possible to know whether Windows widget totally covered by other windows?

We want to create a Windows desktop version of our weather widget
There are 2 special things about the widget.
It consumes a lot of processor time
while active - it displays an
animated picture (Flash without GPU acceleration, unfortunately).
It updates the weather from our
server (frequent server requests from all widget users).
When the user does not look at the widget there is no need for animation and weather loading.
So I have an idea of putting my widget to sleep when it is not visible and hense not used.
Is it possible to detect whether the widget is used or not.
Speaking precisely I need to know whether the widget is covered by other windows?
I mostly interested in Vista/7 gadgets engine, however I also would like to know if this problem is solved in these widget engines
Yahoo widgets
Google desktop
Hope to find some desktop widget guru here.
Pasha
If you InvalidateRect and don't get a subsequent WM_PAINT message, than your window is hidden. You can call UpdateWindow after InvalidateRect to force the WM_PAINT message to happen (or not happen) right away.
So you could do something like this
request server data (and cancel request timer if any)
when data arrives InvalidateRect
when WM_PAINT message arrives, draw the data and set a timer for next request
when timer arrives, goto 1
When you stop getting WM_PAINT messages, you stop re-setting your timer, and you therefor stop requesting updates from the server. When the WM_PAINT message happens (because you are no longer covered). You start requesting data again.