Copyright	(c) 2013 diagrams-lib team (see LICENSE)
License	BSD-style (see LICENSE)
Maintainer	diagrams-discuss@googlegroups.com
Safe Haskell	None
Language	Haskell2010

Diagrams.TrailLike

Contents

The TrailLike class
Constructing TrailLikes

Description

The TrailLike class abstracts over anything which can be constructed from a concretely located Trail, including lines, loops, trails, paths, vertex lists, and diagrams.

Synopsis

The TrailLike class

class (Metric (V t), OrderedField (N t)) => TrailLike t where Source

A type class for trail-like things, i.e. things which can be constructed from a concretely located Trail. Instances include lines, loops, trails, paths, lists of vertices, two-dimensional Diagrams, and Located variants of all the above.

Usually, type variables with TrailLike constraints are used as the output types of functions, like

  foo :: (TrailLike t) => ... -> t

Functions with such a type can be used to construct trails, paths, diagrams, lists of points, and so on, depending on the context.

To write a function with a signature like the above, you can of course call trailLike directly; more typically, one would use one of the provided functions like fromOffsets, fromVertices, fromSegments, or ~~.

Methods

trailLike Source

Arguments

:: Located (Trail (V t) (N t))	The concretely located trail. Note that some trail-like things (e.g. `Trail`s) may ignore the location.
-> t

Instances

(Metric v, OrderedField n) => TrailLike [Point v n] Source	A list of points is trail-like; this instance simply computes the vertices of the trail, using `trailPoints`.
TrailLike t => TrailLike (TransInv t) Source	Translationally invariant things are trail-like as long as the underlying type is.
TrailLike t => TrailLike (Located t) Source	`Located` things are trail-like as long as the underlying type is. The location is taken to be the location of the input located trail.
(Metric v, OrderedField n) => TrailLike (Trail v n) Source	`Trail`s are trail-like; the location is simply ignored.
(Metric v, OrderedField n) => TrailLike (Path v n) Source	Paths are trail-like; a trail can be used to construct a singleton path.
(Metric v, OrderedField n) => TrailLike (Trail' Loop v n) Source	Loops are trail-like. If given a `Trail` containing a line, the line will be turned into a loop using `glueLine`. The location is ignored.
(Metric v, OrderedField n) => TrailLike (Trail' Line v n) Source	Lines are trail-like. If given a `Trail` which contains a loop, the loop will be cut with `cutLoop`. The location is ignored.

Constructing TrailLikes

fromSegments :: TrailLike t => [Segment Closed (V t) (N t)] -> t Source

Construct a trail-like thing from a list of segments, with the origin as the location.

fromSegmentsEx = fromSegments
  [ straight (r2 (1,1))
  , bézier3  (r2 (1,1)) unitX unit_Y
  , straight unit_X
  ]
  # centerXY # pad 1.1

fromLocSegments :: TrailLike t => Located [Segment Closed (V t) (N t)] -> t Source

Construct a trail-like thing from a located list of segments.

fromOffsets :: TrailLike t => [Vn t] -> t Source

Construct a trail-like thing of linear segments from a list of offsets, with the origin as the location.

fromOffsetsEx = fromOffsets
  [ unitX
  , unitX # rotateBy (1/6)
  , unitX # rotateBy (-1/6)
  , unitX
  ]
  # centerXY # pad 1.1

fromLocOffsets :: (V t ~ v, N t ~ n, V (v n) ~ v, N (v n) ~ n, TrailLike t) => Located [v n] -> t Source

Construct a trail-like thing of linear segments from a located list of offsets.

fromVertices :: TrailLike t => [Point (V t) (N t)] -> t Source

Construct a trail-like thing connecting the given vertices with linear segments, with the first vertex as the location. If no vertices are given, the empty trail is used with the origin as the location.

import Data.List (transpose)

fromVerticesEx =
  ( [ pentagon 1
    , pentagon 1.3 # rotateBy (1/15)
    , pentagon 1.5 # rotateBy (2/15)
    ]
    # transpose
    # concat
  )
  # fromVertices
  # closeTrail # strokeTrail
  # centerXY # pad 1.1

(~~) :: (V t ~ v, N t ~ n, TrailLike t) => Point v n -> Point v n -> t Source

Create a linear trail between two given points.

twiddleEx
  = mconcat ((~~) <$> hexagon 1 <*> hexagon 1)
  # centerXY # pad 1.1

explodeTrail :: (V t ~ v, N t ~ n, Additive v, TrailLike t) => Located (Trail v n) -> [t] Source

Given a concretely located trail, "explode" it by turning each segment into its own separate trail. Useful for (say) applying a different style to each segment.

explodeTrailEx
  = pentagon 1
  # explodeTrail  -- generate a list of diagrams
  # zipWith lc [orange, green, yellow, red, blue]
  # mconcat # centerXY # pad 1.1