WPF Brush with Image texture

Using WPF, I have an InkCanvas which has its background set to an image. I want to draw over this image with a brush that has the texture of another image. I know it's possible to use an ImageBrush and set the source of it to an image, but my understanding is you can开发者_开发百科 only paint an entire shape at once (e.g. fill a rectangle). I want to be able to paint on my InkCanvas and wherever I stroke, have this other image draw on top. How can I do this?