DirectX Screenshot crop image help

I need a DirectX Expert to help finish a function I use to take a ingame screenshot using the backbuffer. My screenshot function works fine, I am able to save the screenshot however I want to crop the center of it and save that, instead of the whole image. The resulting size should be 320 x 200 from the center of the screen image. I do not want to use any external classes, or libraries. I am hoping to pass the mapped buffer pData to a function to have it resized/cropped. my function to get screenshot data: D3D11_TEXTURE2D_DESC StagingDesc; ID3D11Texture2D *pBackBuffer = NULL; g_DX11Renderer->m_swapChain->GetBuffer( 0, __uuidof( ID3D11Texture2D ), (LPVOID*)&pBackBuffer ); pBackBuffer->GetDesc(&StagingDesc); [login to view URL] = D3D11_USAGE_STAGING; [login to view URL] = 0; [login to view URL] = D3D11_CPU_ACCESS_READ; [login to view URL] = 0; [login to view URL] = 1; [login to view URL] = 1; [login to view URL] = 1; [login to view URL] = 0; [login to view URL] = DXGI_FORMAT_R8G8B8A8_UNORM; ID3D11Texture2D *pBackBufferStaging = NULL; HRESULT hr = g_DX11Renderer->m_device->CreateTexture2D(&StagingDesc, NULL, &pBackBufferStaging); g_DX11Renderer->m_deviceContext->CopyResource(pBackBufferStaging,pBackBuffer); D3D11_MAPPED_SUBRESOURCE mappedData; g_DX11Renderer->m_deviceContext->Map(pBackBufferStaging, 0, D3D11_MAP_READ, 0, &mappedData); BYTE* bufData = (BYTE*)[login to view URL]; g_DX11Renderer->m_deviceContext->Unmap(pBackBufferStaging,0);