Hello people

I'm currently learning D3D and so far I'm doing good but I ran into a little problem that I'm not sure how to fix. I'm displaying a quad in window mode and when I resize the window the content is stretched. I tried to use IDirect3DDevice9::Reset() but I had 2 problem with that, it's slow and makes the resizing of the window become laggy and still appeared bigger. I wanna be able to see more of my world, not just see it become bigger. I tried to mess up with IDirect3DDevice9::SetViewport and creating a swap chain but it didn't work (I probably didn't do it right).

Does anyone have any advice or could point to a good resource on that subject? (I can't seem to find any)

Thank you