How to take a screenshot in WP8

Question

So I have a DrawingSurfaceBackgroundGrid inside of a PhoneApplicationPage, in my WP8 app; and I would like to take a screenshot. As far as I can tell (from google), there isn't a call to simply "take a screenshot". What people are doing is using a WriteableBitmap, like this:

WriteableBitmap wbmp = new WriteableBitmap(test, null);
wbmp.SaveJpeg(isoStream2, wbmp.PixelWidth, wbmp.PixelHeight, 0, 100);

I have tried test as both the DrawingSurfaceBackgroundGrid, and the PhoneApplicationPage. Neither of these are working for me. Could it have something to do with the fact that I am rendering everything using RenderTargets and pixel shaders (in SharpDX)? I just get a black image. Here is the code to save the image:

IsolatedStorageFile isoStore = IsolatedStorageFile.GetUserStoreForApplication();

using (IsolatedStorageFileStream isoStream2 = new IsolatedStorageFileStream("new.jpg", FileMode.OpenOrCreate, isoStore))
{
    WriteableBitmap wbmp = new WriteableBitmap(test, null);
    wbmp.SaveJpeg(isoStream2, wbmp.PixelWidth, wbmp.PixelHeight, 0, 100);
}

But like I said, it just creates a black image.

Any ideas?

Answer 1

Tried your code as is with the exception of changing "test" to the name of the root grid, in my app x:Name="LayoutRoot" , and works fine! Just replace test with the element you want to capture, the root-grid name for whole page or sub element name for just that element.

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BTW thanks for the code, one more to squirrel away.

Answer 2

I am using the code below. Though it is saving to the Media Gallery.

WriteableBitmap bmpCurrentScreenImage = new WriteableBitmap((int)this.ActualWidth, (int)this.ActualHeight);
bmpCurrentScreenImage.Render(LayoutRoot, new MatrixTransform());
bmpCurrentScreenImage.Invalidate();
using (var stream = new MemoryStream())
{
    // Save the picture to the Windows Phone media library.
    bmpCurrentScreenImage.SaveJpeg(stream, bmpCurrentScreenImage.PixelWidth, bmpCurrentScreenImage.PixelHeight, 0, quality);
    stream.Seek(0, SeekOrigin.Begin);

    var picture = new MediaLibrary().SavePicture(name, stream);
    return picture.GetPath();
}