Foxit pdf SDK for UWP

//Render the pdf page, then save it to a bitmap file.
void FunctionDemo::MainPage::render_Click(Platform::Object^ sender, Windows::UI::Xaml::RoutedEventArgs^ e)
{
	StorageFolder^ documentFolder = Windows::Storage::KnownFolders::DocumentsLibrary;
	std::shared_ptr<fsbitmap^> spBitmap = std::make_shared<fsbitmap^>(nullptr);
	create_task(documentFolder->GetFileAsync("FoxitBigPreview.pdf")).then([=](StorageFile^ file) {
		try
		{
			m_doc = ref new FSPDFDoc(file, 0);
			if (!m_doc)
			{
				return;
			}
			
			FSErrorCode code = m_doc->Load("");
			if (code != FSErrorCode::e_errSuccess) {
				return;
			}

			FSPDFPage^ page = m_doc->GetPage(0);
			if (!page->IsParsed())
			{
				page->StartParse(0, nullptr, false);
			}
			//create bitmap
			int pageWidth = (int)page->GetWidth();
			int pageHeight = (int)page->GetHeight();
			*spBitmap = ref new FSBitmap(pageWidth, pageHeight, FSDIBFormat::e_dibRgb32, nullptr, 0);
			if (!(*spBitmap)) {
				return;
			}
			(*spBitmap)->FillRect(0xffffffff, nullptr);

			//init renderer
			FSRenderer^ render = ref new FSRenderer((*spBitmap), false);
			if (!render) {
				return;
			}

			//set different kinds of properties
			render->SetRenderContentFlags((int)FSRenderContentFlag::e_renderPage);
			render->SetTransformAnnotIcon(true);
			render->SetColorMode(FSRenderColorMode::e_colorModeNormal);
			render->SetForceHalftone(true);

			FSMatrix^ matrix = page->GetDisplayMatrix(0, 0, pageWidth, pageHeight, FSRotation::e_rotation0);
			render->StartRender(page, matrix, nullptr);

		}
		catch (Platform::Exception^ e)
		{
			OutputDebugString(e->Message->Data());
		}
	}).then([=]()
	{
		return documentFolder->CreateFileAsync("Output_Render.bmp", CreationCollisionOption::ReplaceExisting);
	}).then([=](StorageFile^ file)
	{
		FSImage^ img = ref new FSImage();
		img->AddFrame((*spBitmap));
		if(img->SaveAs(file, "bmp"))
			this->showMesseageDialog("", "The output file is saved to:" + file->Path);
		else
			this->showMesseageDialog("", "error!");
	});
	
}