Copyright | (c) 2011 diagrams-lib team (see LICENSE) |
---|---|
License | BSD-style (see LICENSE) |
Maintainer | diagrams-discuss@googlegroups.com |
Safe Haskell | Safe-Inferred |
Language | Haskell2010 |
Diagrams.Path
Description
This module defines paths, which are collections of concretely located Trail
s. Many drawing systems (cairo, svg, ...) have a similar notion of "path". Note that paths with multiple trails are necessary for being able to draw e.g. filled objects with holes in them.
Synopsis
- newtype Path v n = Path [Located (Trail v n)]
- pathTrails :: Path v n -> [Located (Trail v n)]
- class ToPath t where
- pathFromTrail :: (Metric v, OrderedField n) => Trail v n -> Path v n
- pathFromTrailAt :: (Metric v, OrderedField n) => Trail v n -> Point v n -> Path v n
- pathFromLocTrail :: (Metric v, OrderedField n) => Located (Trail v n) -> Path v n
- pathPoints :: (Metric v, OrderedField n) => Path v n -> [[Point v n]]
- pathVertices' :: (Metric v, OrderedField n) => n -> Path v n -> [[Point v n]]
- pathVertices :: (Metric v, OrderedField n) => Path v n -> [[Point v n]]
- pathOffsets :: (Metric v, OrderedField n) => Path v n -> [v n]
- pathCentroid :: (Metric v, OrderedField n) => Path v n -> Point v n
- pathLocSegments :: (Metric v, OrderedField n) => Path v n -> [[Located (Segment Closed v n)]]
- fixPath :: (Metric v, OrderedField n) => Path v n -> [[FixedSegment v n]]
- scalePath :: (HasLinearMap v, Metric v, OrderedField n) => n -> Path v n -> Path v n
- reversePath :: (Metric v, OrderedField n) => Path v n -> Path v n
- explodePath :: (V t ~ v, N t ~ n, TrailLike t) => Path v n -> [[t]]
- partitionPath :: (Located (Trail v n) -> Bool) -> Path v n -> (Path v n, Path v n)
Paths
A path is a (possibly empty) list of Located
Trail
s. Hence, unlike trails, paths are not translationally invariant, and they form a monoid under superposition (placing one path on top of another) rather than concatenation.
Instances
pathTrails :: Path v n -> [Located (Trail v n)] Source #
Extract the located trails making up a Path
.
Constructing paths
Since paths are TrailLike
, any function producing a TrailLike
can be used to construct a (singleton) path. The functions in this section are provided for convenience.
Type class for things that can be converted to a Path
.
Note that this class is very different from TrailLike
. TrailLike
is usually the result of a library function to give you a convenient, polymorphic result (Path
, Diagram
etc.).
Instances
ToPath (Located (Segment Closed v n)) Source # | |
ToPath (Located (Trail v n)) Source # | |
ToPath (Located (Trail' l v n)) Source # | |
ToPath (Located [Segment Closed v n]) Source # | |
ToPath a => ToPath [a] Source # | |
ToPath (Path v n) Source # | |
ToPath (FixedSegment v n) Source # | |
Defined in Diagrams.Path Methods toPath :: FixedSegment v n -> Path (V (FixedSegment v n)) (N (FixedSegment v n)) Source # | |
ToPath (Trail v n) Source # | |
ToPath (Trail' l v n) Source # | |
pathFromTrail :: (Metric v, OrderedField n) => Trail v n -> Path v n Source #
Convert a trail to a path beginning at the origin.
pathFromTrailAt :: (Metric v, OrderedField n) => Trail v n -> Point v n -> Path v n Source #
Convert a trail to a path with a particular starting point.
pathFromLocTrail :: (Metric v, OrderedField n) => Located (Trail v n) -> Path v n Source #
Convert a located trail to a singleton path. This is equivalent to trailLike
, but provided with a more specific name and type for convenience.
Eliminating paths
pathPoints :: (Metric v, OrderedField n) => Path v n -> [[Point v n]] Source #
Extract the points of a path, resulting in a separate list of points for each component trail. Here a point is any place where two segments join; see also pathVertices
and trailPoints
.
This function allows you "observe" the fact that trails are implemented as lists of segments, which may be problematic if we want to think of trails as parametric vector functions. This also means that the behavior of this function may not be stable under future changes to the implementation of trails and paths. For an unproblematic version which only yields vertices at which there is a sharp corner, excluding points differentiable points, see pathVertices
.
This function is not re-exported from Diagrams.Prelude; to use it, import Diagrams.Path.
pathVertices' :: (Metric v, OrderedField n) => n -> Path v n -> [[Point v n]] Source #
Extract the vertices of a path, resulting in a separate list of vertices for each component trail. Here a vertex is defined as a non-differentiable point on the trail, i.e. a sharp corner. (Vertices are thus a subset of the places where segments join; if you want all joins between segments, see pathPoints
.) The tolerance determines how close the tangents of two segments must be at their endpoints to consider the transition point to be differentiable. See trailVertices
for more information.
pathVertices :: (Metric v, OrderedField n) => Path v n -> [[Point v n]] Source #
Like pathVertices'
, with a default tolerance.
pathOffsets :: (Metric v, OrderedField n) => Path v n -> [v n] Source #
Compute the total offset of each trail comprising a path (see trailOffset
).
pathCentroid :: (Metric v, OrderedField n) => Path v n -> Point v n Source #
Compute the centroid of a path (i.e. the average location of its vertices; see pathVertices
).
pathLocSegments :: (Metric v, OrderedField n) => Path v n -> [[Located (Segment Closed v n)]] Source #
Convert a path into a list of lists of located segments.
fixPath :: (Metric v, OrderedField n) => Path v n -> [[FixedSegment v n]] Source #
Convert a path into a list of lists of FixedSegment
s.
Modifying paths
scalePath :: (HasLinearMap v, Metric v, OrderedField n) => n -> Path v n -> Path v n Source #
Scale a path using its centroid (see pathCentroid
) as the base point for the scale.
reversePath :: (Metric v, OrderedField n) => Path v n -> Path v n Source #
Reverse all the component trails of a path.
Miscellaneous
explodePath :: (V t ~ v, N t ~ n, TrailLike t) => Path v n -> [[t]] Source #
"Explode" a path by exploding every component trail (see explodeTrail
).