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	Chapters
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CHAPTER 10. DRAWING OPTIONS

=> :line-dashes [Option]
=> line-style-dashes line-style [Generic Function]
Controls whether lines or arcs are drawn as dashed figures, and if so, what the dashing pattern
is. Possible values are:

• nil - lines are drawn solid, with no dashing. This is the default.
  
  
• t - lines are drawn dashed, with a dash pattern that is unspecified and may vary with
  the rendering engine. This allows the underlying display substrate to provide a default
  dashed line for the programmer whose only requirement is to draw a line that is visually
  distinguishable from the default solid line.
  
  
• A sequence - specifies a sequence, usually a vector, controlling the dash pattern of a drawing
  function. It is an error if the sequence does not contain an even number of elements. The
  elements of the sequence are lengths (as real numbers) of individual components of the
  dashed line or arc. The odd elements specify the length of inked components, the even
  elements specify the gaps. All lengths are expressed in the units described by line-style-
  unit.
  

(See also make-contrasting-dash-patterns.)

10.3.2 Contrasting Dash Patterns

=> make-contrasting-dash-patterns n &optional k [Function]
If k is not supplied, this returns a vector of n dash patterns with recognizably different appear-
ance. Elements of the vector are guaranteed to be acceptable values for :dashes, and do not
include nil, but their class is not otherwise specified. The vector is a fresh object that may be
modified.

If k is supplied, it must be an integer between 0 and n + 1 (inclusive), in which case make-
contrasting-dash-patterns returns the k'th dash-pattern rather than returning a vector of
dash-patterns.

If the implementation does not have n different contrasting dash patterns, make-contrasting-
dash-patterns signals an error. This will not happen unless n is greater than eight.

=> contrasting-dash-pattern-limit port [Generic Function]
Returns the number of contrasting dash patterns that can be rendered on any medium on the
port port. Implementations are encouraged to make this as large as possible, but it must be
at least 8. All classes that obey the port protocol must implement a method for this generic
function.

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Page 85	Table of Contents	Index	Page 87
	Chapters
	1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 A, B, C, D, E