13.6 Indirect Inks

Drawing with an indirect ink is the same as drawing another design named directly. For example, +foreground-ink+ is a design that draws the medium's foreground design and is the default value of the :ink drawing option. Indirect inks exist for the benefit of output recording. For example, one can draw with +foreground-ink+, change to a different medium-foreground, and replay the output record; the replayed output will come out in the new color. [annotate]

[indirect ink, Concept← A Glossary]

You can change the foreground or background design of a medium at any time. This changes the contents of the medium's drawing plane. The effect is as if everything on the drawing plane is erased, the background design is drawn onto the drawing plane, and then everything that was ever drawn (provided it was saved in the output history) is drawn over again, using the medium's new foreground and background. [annotate]

If an infinite recursion is created using an indirect ink, an error is signalled when the recursion is created, when the design is used for drawing, or both. [annotate]

Two indirect inks are defined, but no advertised way is provided to create more of them. [annotate]

+foreground-ink+   [Constant]
+background-ink+   [Constant]