set-stipple in pen%

Sets the pen stipple bitmap, which must be an 8 x 8 monochrome bitmap or #f, which turns off the stipple bitmap.

A bitmap cannot be used as a stipple if it is selected into a bitmap-dc% object; if the given bitmap is selected into a bitmap-dc% object, an exn:fail:contract exception is raised. A pen cannot be modified if it was obtained from a pen-list% or while it is selected into a drawing context.

A pen's stipple is not used in a smoothing mode, except for a post-script-dc% (which is always in smoothed mode).

• (send a-pen set-stipple stipple) -> void
     stipple : bitmap% object or #f