GraphicsCaptureItem.CreateFromVisual() with a WPF element? about windows.ui.composition-win32-samples HOT 9 CLOSED

Unfortunately that isn't possible at this time. WPF does not use WinRT Visuals to compose its UI, to the compositor it just looks like a single swap chain. The best that can be done currently is to capture the window using its HWND to create a GraphicsCaptureItem.

from windows.ui.composition-win32-samples.

For example, if you know the window of your application that you want to capture you can do something like this:

var myWPFWindow = /* Your WPF window */;
var interop = new WindowInteropHelper(myWPFWindow);
var windowHandle = interop.Handle;

var captureItem = CaptureHelper.CreateItemForWindow(windowHandle);

You can find the CaptureHelper static class here.

from windows.ui.composition-win32-samples.

Many thanks for this. Unfourtunately I don't think think this will work for what I'm trying to do. I'm rendering some graphics in a WPF window which I need to be hidden from the user. Unfourtunately as soon as I set Window Visibility to hidden, the capture stops working.

from windows.ui.composition-win32-samples.

@joedemax graphics capture in UWP is the same: capture doesn't work on items that are hidden (or "Collapsed" in UWP/Xaml). The workaround, in UWP/Xaml at least, is to move the item off-screen without collapsing it.

from windows.ui.composition-win32-samples.

@Zofware have you had any success with this? I found as soon as a some of the window was offscreen, that portion would no longer be capture (Using the HWND capture method)

from windows.ui.composition-win32-samples.

Applications may choose not to redraw portions of themselves that are off-screen. It really depends on how these applications compose themselves. For example, if an application uses DirectComposition or Windows.UI.Composition (e.g. UWP XAML applications), that application should redraw just fine when it is off-screen. Many D3D applications will draw fine when they are off-screen. However applications that rely on their GDI redirection surface may not (depending on how they react to WM_PAINT messages).

How are you rendering your graphics to your window? Are you mixing it with other WPF content or just using it as a host?

from windows.ui.composition-win32-samples.

@joedemax FWIW I use the offscreen technique with a UWP Xaml app. I haven't tried it with anything else. I'll defer to @robmikh for how it should work with HWND capture.

from windows.ui.composition-win32-samples.

@robmikh would I be able to use the same tactic to capture a WPF window that is offscreen?

from windows.ui.composition-win32-samples.

I don’t believe a WPF window will repaint while offscreen.

from windows.ui.composition-win32-samples.