Do you ever have thoughts about drawing live masks, projecting a web search or just using any applications window's in CoGe?
Syphoner gives the ability to share the graphical window's content of any open application and stream it in real-time, full frame, to any Syphon client application. You can browse the web or draw a vector mask in your favourite software, and display instantly the result into your VJ or projection tool app." - via Syphoner website
That is probably could not be easier:
Tip: you can crop the image in Syphoner to remove the window title bar.
Processing 2.0 sketch to CoGe. Just as mentioned, open a Processing sketch, select its output window via Syphoner, create a SyphonSource in CoGe, select Syphoner, and here you go.
Pixelmator drawing to CoGe. If you missed Pixelmator you definitely need to take a look into. Its a beautiful and powerful image editing app where you can use your custom Quartz Composer effects as filters. Anyway, just do the steps mentioned above.