10.3.1 Setting the graphics state

The graphics state values associated with a drawing function call to a graphics port are set by one of three mechanisms.

1. Enumeration in the drawing function call. For example:

 (draw-line port 1 1 100 100 

            :thickness 10             

            :scale-thickness nil         

            :foreground :red)

2. Bound using the with-graphics-state macro. For example:

(with-graphics-state (port :thickness 10

                             :scale-thickness nil    

                             :foreground :red)     

    (draw-line port 1 1 100 100)  

    (draw-rectangle port 2 2 40 50 :filled t))

3. Set by the set-graphics-state function. For example:

(set-graphics-state port :thickness 10                                

                        :scale-thickness nil  

                        :foreground :red)

The first two mechanisms change the graphics state temporarily. The last one changes it permanently, effectively altering the "default" state.