I'm trying to get my head around how the graphics-class works. I need to say that I used cinder before, where for drawing you called something like gl::drawSolidRectangular(). So I was shure that I called a GL-function.
But I don't know what Graphics::fillRectangular() is doing, if it is basically the same???
There must be literally thousands of examples of this in the demo projects and the codebase!
Try grepping the juce source tree for "void paint" or "Graphics&" or "g.fillRect" etc.. You'll find a whole bunch of paint methods that I'd have thought should be pretty self-explanatory. Not to mention the extensive help describing the Graphics class itself: http://www.juce.com/api/classGraphics.html