// how to get the viewport, the frame containing the viewport and how to get the size of the viewport and how to resize the frame containing the viewport.
//Running this within the editor’s viewport pretty much crashes the editor.
const FVector2D viewportSize = FVector2D(GEngine->GameViewport->Viewport->GetSizeXY());
FViewportFrame* viewPortFrame = GEngine->GameViewport->ViewportFrame;
const FString viewPortInfoString = viewportSize.ToString();
GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Blue, viewPortInfoString);
viewPortFrame->ResizeFrame(0,0,EWindowMode::Type::Windowed ,1024,786);