For FGQCanvas, see:
https://sourceforge.net/p/flightgear/ma ... /36724213/Otherwise (using just a browser):
- enable mongoose (Phi)
- start flightgear
- start your browser
- open Phi via the browser
- edit the URL to append /canvasimage?type=png&canvasindex=0
- change the index as needed, i.e. by navigating to the /canvas location via the property browser
PS: This may still not be the perfect tool for the job, especially when dealing with complex avionics like the FG1000 - like I said, it's "streaming" the raster image over http - FGQCanvas works differently, i.e. by copying/replicating state over http and re-rendering the underlying primitive.