Auto focus camera without preview - win-universal-app

I am running Win10 IoT on a pi 2. I need to be able to take pictures that are focused but cannot get the focus working. The application is a background app so I don't have a way of previewing the camera on a display. Is there any way of doing this? Currently I have
await _mediaCapture.StartPreviewAsync();
_mediaCapture.VideoDeviceController.FocusControl.Configure(new FocusSettings
{
Mode = FocusMode.Continuous,
WaitForFocus = true
});
await _mediaCapture.VideoDeviceController.FocusControl.FocusAsync();
await _mediaCapture.CapturePhotoToStreamAsync(ImageEncodingProperties.CreateJpeg(), stream);
await _mediaCapture.StopPreviewAsync();
but I am getting the error
WinRT information: Preview sink not set
when I try to focus. All of the examples I've seen online show that the preview is output to a control and I assume it wires a sink up automagically. Is there a way to do this manually through code? Possibly without the preview?

I wonder if the code may work even without FocusControl.
I propose you follow Customer Media Sink implementation example and use of StartPreviewToCustomSinkIdAsync method described at http://www.codeproject.com/Tips/772038/Custom-Media-Sink-for-Use-with-Media-Foundation-To

I didn't find a way to do this. I ended up converting the background app to a UI app with a Page containing a CaptureElement control in order to preview and focus.

Instead of adding a UI, just create a CaptureElement and set the source to the _mediaCapture before calling await _mediaCapture.StartPreviewAsync();
Something like:
_captureElement = new CaptureElement { Stretch = Stretch.Uniform };
_mediaCapture = new MediaCapture();
await _mediaCapture.InitializeAsync(...);
_captureElement.Source = _mediaCapture;
await _mediaCapture.StartPreviewAsync();

Related

Can I trigger the Hololens Calibration sequence from inside my application?

I have a hololens app I am creating that requires the best accuracy possible for hologram placement. This application will be used by numerous individuals. Whenever I try to show the application progress, I have to have the user go through the calibration process, otherwise the holograms appear to have way too much drift.
I would like to be able to call the hololens calibration process automatically when the application opens. Later, after I set up user authentication and id management, I will call the calibration process when a new user is found.
https://learn.microsoft.com/en-us/windows/mixed-reality/calibration
I have looked into the calibration (via the above documentation and elsewhere) and it seems that all it is setting is IPD. However the alternative solutions I have found that allow for dynamic ipd adjustment appear to be invalid for UWP Store apps. This makes them unusable for me.
I am looking for any help or direction, or if this is even possible. Thank you.
Yes, it is possible to to this, you need to use the LaunchUriAsync protocol to launch the following URI: ms-hololenssetup://EyeTracking
Here is an example implementation, obtained from the LaunchUri example in MRTK
public void LaunchEyeTracking()
{
#if WINDOWS_UWP
UnityEngine.WSA.Application.InvokeOnUIThread(async () =>
{
bool result = await global::Windows.System.Launcher.LaunchUriAsync(new System.Uri("ms-hololenssetup://EyeTracking"));
if (!result)
{
Debug.LogError("Launching URI failed to launch.");
}
}, false);
#else
Debug.LogError("Launching eye tracking not supported Windows UWP");
#endif
}

UWP, Playing sound is stop sometime

in UWP application, Sometime Playing sound is stop.
await Execute.OnUIThreadAsync(async () =>
{
var element = new MediaElement();
var uri = new Uri($"ms-appx:///Assets/sound/abc.wav");
StorageFile sf = await StorageFile.GetFileFromApplicationUriAsync(uri);
var stream = await sf.OpenAsync(Windows.Storage.FileAccessMode.Read);
element.SetSource(stream, "");
element.Play();
});
I think, This UIThread job finish immediately.
but My sound file has 1 minutes length, Then,
The task was closed. then, Sound can not play by end.
How should I write to play sound ?
Refer to the following MSDN doc:Play media in the background. To support your music playing in background, you need to check the requirements from "Requirements for background audio". Actually you've mentioned that it is "sometime", so I'm not so sure whether you've already used the solution from the above doc. But if you haven't, you need to refer to that article, enable capbility and then manage both the transitioning and also notice the memory.

Chrome screen sharing get monitor info

I implemented chrome extension which using chrome.desktopCapture.chooseDesktopMedia to retrieve screen id.
This is my background script:
chrome.runtime.onConnect.addListener(function (port) {
port.onMessage.addListener(messageHandler);
// listen to "content-script.js"
function messageHandler(message) {
if(message == 'get-screen-id') {
chrome.desktopCapture.chooseDesktopMedia(['screen', 'window'], port.sender.tab, onUserAction);
}
}
function onUserAction(sourceId) {
//Access denied
if(!sourceId || !sourceId.length) {
return port.postMessage('permission-denie');
}
port.postMessage({
sourceId: sourceId
});
}
});
I need to get shared monitor info(resolution, landscape or portrait).
My question is: If customer using more than one monitor, how can i determine which monitor he picked?
Can i add for example "system.display" permissions to my extension and get picked monitor info from "chrome.system.display.getInfo"?
You are right. You could add system.display permission and call chrome.system.display.getDisplayLayout(callbackFuncion(DisplayLayout)) and handle the DisplayLayout.position in the callback to get the layout and the chrome.system.display.getInfo to handle the array of displayInfo in the callback. You should look for 'isPrimary' value
This is a year old question, but I came across it since I was after the same information and I finally managed to figure how you can identify which monitor the user selected for screen-sharing in Chrome.
First of all: this information will not come from the extension that you probably built for screen-sharing in Chrome, because:
The chrome.desktopCapture.chooseDesktopMedia API callback only returns a sourceId, which is a string that represents a stream id, that you can then use to call the getMediaSource API to build the media stream.
The chrome.system.display.getInfo will give you a list of the displays, yes, but from that info you can't tell which one is being shared, and there is no way to match the sourceId with any of the fields returned for each display.
So... the solution I've found comes from the MediaStream object itself. Once you have the stream, after calling getMediaSource, you need to get the video track, and in there you will find a property called "label". This label gives you an idea of which screen the user picked.
You can get the video track with something like:
const videoTrack = mediaStream.getVideoTracks()[0];
(Check the getVideoTracks API here: https://developer.mozilla.org/en-US/docs/Web/API/MediaStream/getVideoTracks).
If you print that object, you will see the "label" field. In Chrome screen 1 shows as "0:0", whereas screen 2 shows as "1:0", and I assume screen i would be "i-1:0" (I've only tested with 2 screens).
Here is a capture of that object printed in the console:
And not only works for Chrome, but for other browsers that implement it! In Firefox they show up as "Screen i":
Also, if you check Chrome chrome://webrtc-internals you'll see this is what they show in the addStream event:
And that's it! It's not ideal, since this is a label, more than a real screen identifier, but well, it's something to work with. Once you have the screen identified, in Chrome you can work with the chrome.system.display.getInfo to get information for that display.

How to attach mouse event listeners to embedded nsIWebBrowser in C++

I've embedded an nsIWebBrowser in my application. Because I'm just generating HTML for it on the fly, I'm using OpenStream, AppendToStream, and CloseStream to add content. What I need is to add event listeners for mouse movement over the web browser as well as mouse clicks. I've read documentation and tried lots of different things, but nothing I have tried has worked. For instance, the code below would seem to do the right thing, but it does nothing:
nsCOMPtr<nsIDOMWindow> domWindow;
mWebBrowser->GetContentDOMWindow(getter_AddRefs(domWindow));
if (!mEventTarget) {
mEventTarget = do_QueryInterface(domWindow);
if (mEventTarget)
mEventTarget->AddEventListener(NS_LITERAL_STRING("mouseover"), (nsIDOMEventListener *)mEventListener, PR_FALSE);
}
Perhaps it isn't working because this is run during initialization, but before any content is actually added. However, if I add it during AppendStream, or CloseStream, it segfaults.
Please tell me a straightforward way to do this.
Well, here's the answer:
nsCOMPtr<nsIDOMEventTarget> cpEventTarget;
nsCOMPtr<nsIDOMWindow> cpDomWin;
m_pWebBrowser->GetContentDOMWindow (getter_AddRefs(cpDomWin));
nsCOMPtr<nsIDOMWindow2> cpDomWin2 (do_QueryInterface (cpDomWin));
cpDomWin2->GetWindowRoot(getter_AddRefs(cpEventTarget));
rv = cpEventTarget->AddEventListener(NS_LITERAL_STRING("mousedown"),
m_pBrowserImpl, PR_FALSE);

Flash trace output in firefox, linux

I'm developing an applications which I've got running on a server on my linux desktop. Due to the shortcomings of Flash on Linux (read: too hard) I'm developing the (small) flash portion of the app in Windows, which means there's a lot of frustrating back and forth. Now I'm trying to capture the output of the flash portion using flash tracer and that is proving very difficult also. Is there any other way I could monitor the output of trace on linux? Thanks...
Hope this helps too (for the sake of google search i came from):
In order to do trace, you need the debugger version of Flash Player from
http://www.adobe.com/support/flashplayer/downloads.html (look for "debugger" version specifically - they are hard to spot on first look)
Then an mm.cfg file in your home containing
ErrorReportingEnable=1 TraceOutputFileEnable=1 MaxWarnings=50
And then you are good to go - restart the browser. When traces start to fill in, you will find the log file in
~/.macromedia/Flash_Player/Logs/flashlog.txt
Something like
tail ~/.macromedia/Flash_Player/Logs/flashlog.txt -f
Should suffice to follow the trace.
A different and mind-bogglingly simple workaround that I've used for years is to simply create an output module directly within the swf. All this means is a keyboard shortcut that attaches a MovieClip with a textfield. All my traces go to this textfield instead of (or in addition to) the output window. Over the years I've refined it of course, making the window draggable, resizable, etc. But I've never needed any other approach for simple logging, and it's 100% reliable and reusable across all platforms.
[EDIT - response to comment]
There's no alert quite like javascript's alert() function. But using an internal textfield is just this simple:
ACTIONSCRIPT 1 VERSION
(See notes at bottom)
/* import ExternalInterface package */
import flash.external.*;
/* Create a movieclip for the alert. Set an arbitrary (but very high) number for the depth
* since we want the alert in front of everything else.
*/
var alert = this.createEmptyMovieClip("alert", 32000);
/* Create the alert textfield */
var output_txt = alert.createTextField("output_txt", 1, 0, 0, 300, 200);
output_txt.background = true;
output_txt.backgroundColor = 0xEFEFEF;
output_txt.selectable = false;
/* Set up drag behaviour */
alert.onPress = function()
{
this.startDrag();
}
alert.onMouseUp = function()
{
stopDrag();
}
/* I was using a button to text EI. You don't need to. */
testEI_btn.onPress = function()
{
output_txt.text = (ExternalInterface.available);
}
Notes: This works fine for AS1, and will translate well into AS2 (best to use strong data-typing if doing so, but not strictly required). It should work in Flash Players 8-10. ExternalInterface was added in Flash 8, so it won't work in previous player versions.
ACTIONSCRIPT 3 VERSION
var output_txt:TextField = new TextField();
addChild(output_txt);
output_txt.text = (String(ExternalInterface.available));
If you want to beef it out a bit:
var alert:Sprite = new Sprite();
var output_txt:TextField = new TextField();
output_txt.background = true;
output_txt.backgroundColor = 0xEFEFEF;
output_txt.selectable = false;
output_txt.width = 300;
output_txt.height = 300;
alert.addChild(output_txt);
addChild(alert);
alert.addEventListener(MouseEvent.MOUSE_DOWN, drag);
alert.addEventListener(MouseEvent.MOUSE_UP, stopdrag);
output_txt.text = (String(ExternalInterface.available));
function drag(e:MouseEvent):void
{
var alert:Sprite = e.currentTarget as Sprite;
alert.startDrag();
}
function stopdrag(e:MouseEvent):void
{
var alert:Sprite = e.currentTarget as Sprite;
alert.stopDrag();
}
[/EDIT]
If you only need the trace output at runtime, you can use Firebug in Firefox and then use Flash.external.ExternalInterface to call the console.log() Javascript method provided by Firebug.
I've used that strategy multiple times to a large degree of success.
Thunderbolt is a great logging framework with built-in firebug support.
I use the flex compiler on linux to build actionscript files, [embed(source="file")] for all my assets including images and fonts, I find actionscript development on linux very developer friendly.
Then again, I'm most interested in that flash has become Unix Friendly as aposed to the other way around :)
To implement FlashTracer, head to the following address and be sure you have the latest file. http://www.sephiroth.it/firefox/flashtracer/ . Install it and restart the browser.
Head over to adobe and get the latest flash debugger. Download and install the firefox version as FlashTracer is a firefox addition.
Now that firefox has the latest flash debugger and flash tracer we need to locate mm.cfg
Location on PC: C:\Documents and Settings\username
Inside of mm.cfg should be:
ErrorReportingEnable=1
TraceOutputFileEnable=1
MaxWarnings=100 //Change to your own liking.
Once that is saved, open firefox, head to the flash tracer window by heading to tools > flash tracer. In the panel that pops up there is two icons in the bottom right corner, click the wrench and make sure the path is set to where your log file is being saved. Also check to see that flash tracer is turned on, there is a play/pause button at the bottom.
I currently use this implementation and hope that it works for you. Flash Tracer is a little old, but works with the newest versions of FireFox. I am using it with FireFox 3.0.10.

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