Run time error 'System.AccessViolationException' when trying to run the Face detection example.

[AndrewKaplanovsky]

Hi,

When I try to run the face detection example, I get this error:

An unhandled exception of type 'System.AccessViolationException' occurred in Xamarin.Forms.Platform.WinRT.DLL

Additional information: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

I tried to run the following solutions:

• FaceDetection.WinPhone81
• FaceDetection.Windows

Both raise the same error.

Project FaceDetection, MainPage.xaml.cs, private void OnDetectButtonClicked(object sender, EventArgs args):

if (objects.Length > 0) { var marker = new RectanglesMarker(objects, Color.FromArgb(0xff, 0xff, 0x00, 0xff));

     var stream = new MemoryStream();
     marker.Apply(this.bitmap).Save(stream, ImageFormat.Jpeg); <---- Here I check the stream in debug mode, and it is empty after saving the image into it

     this.ImageView.Source = this.GetImageSourceFromStream(stream);

}

Regards, Andrew Kaplanovsky

[anders9ustafsson]

@AndrewKaplanovsky Which versions of the Accord, Shim and Shim.Drawing libraries are you using? It's been a while since I updated the references in these projects, this might play a role.

I will look closer into this issue when time permits.

[AndrewKaplanovsky]

Hi Anders,

In the app I'm developing: Accord 3.0.2.60302 Shim 2.2.0 Shim.Drawing 3.0.0

In accord-samples that I downloaded from GH, FaceDetection: Accord 3.0.2.50804 Shim 1.0.2.50909 Shim.Drawing 2.2.5.50526

In both cases I get the same error:

When I create a new Stream, I see that its length is zero

After the Bitmap is saved into the stream, its length is still zero

After that the app fails with the 'System.AccessViolationException' trying to display the processed image.

Thank you, Andrew

[anders9ustafsson]

OK, I have looked a little closer into this issue, and it seems like there is a problem with Bitmap.Save for the Universal (8.1) platform. I will attempt a bug fix as soon as possible. In the mean time, many thanks for reporting, @AndrewKaplanovsky !

[AndrewKaplanovsky]

@anders9ustafsson, thank you so much for your help! I'll wait for the fix.

[anders9ustafsson]

@AndrewKaplanovsky I have implemented a fix and verified that it works. In a short while I will publish a new Shim.Drawing release with the bug fix included.

[AndrewKaplanovsky]

@anders9ustafsson, thank you very much!

[AndrewKaplanovsky]

@anders9ustafsson Hi Anders, sorry for disturbing you, but when it is possible to expect the fixed version of the Shim.Drawing dll for the Universal platform published?

[anders9ustafsson]

@AndrewKaplanovsky I am sorry about the delay, quite a few things have gotten in the way. I'll see what I can do within the next couple of days, but I am afraid I cannot promise anything for sure.

[anders9ustafsson]

@AndrewKaplanovsky I have now published version 3.0.1 of Shim.Drawing on NuGet, with the fix for Image.Save on Windows Universal. Please give it a try and see if it works sufficiently for you.

[AndrewKaplanovsky]

Anders, thank you very much, it works now!