Viewport stretching in DX8

[Fox]

Hello everyone,

I'm working on a retro-style RPG that runs in resolution 320x240 (windowed). Since this would be too small to play I'm rendering the scene into a 640x480 sized PictureBox. The problem is that DirectX automatically applies some smoothing filter and the whole picture looks unsharp (see attachment). How can I turn this off?

Next step would be to apply a SAL filter or something, is there a dll I can easily use?

Thanks,

Fox