Improving the error message when drawing methods are used outside setup/draw (and not in static mode)?

[villares]

As @vsquared has shown initially at #486, the error message Cannot invoke "processing.core.PGraphics.line(float, float, float, float)" because "this.g" is null can be a bit confusing for those getting started with py5/Processing. Maybe we could add to it some complementary friendly advice?

[hx2A]

py5's error handling is activate for running py5 Sketches. If a user attempts to call a py5 method outside of a running Sketch, the exception is not caught by anything py5 can use to intervene and provide a better message. I agree that the message is confusing. I will need to think about what can be done here.

[villares]

I see the problem :(

[hx2A]

I added it to my list of things to investigate. When I come up with ideas or a solution I'll let you know!