diagrams-lib-1.3.0.8: Embedded domain-specific language for declarative graphics

Copyright | (c) 2014 diagrams-lib team (see LICENSE)
License | BSD-style (see LICENSE)
Maintainer | diagrams-discuss@googlegroups.com
Safe Haskell | None
Language | Haskell2010

Diagrams.Direction

Description

Type for representing directions, polymorphic in vector space

Synopsis

- data Direction v n
- _Dir :: Iso' (Direction v n) (v n)
- direction :: v n -> Direction v n
- dir :: v n -> Direction v n
- fromDirection :: (Metric v, Floating n) => Direction v n -> v n
- fromDir :: (Metric v, Floating n) => Direction v n -> v n
- angleBetweenDirs :: (Metric v, Floating n) => Direction v n -> Direction v n -> Angle n
- dirBetween :: (Additive v, Num n) => Point v n -> Point v n -> Direction v n

# Documentation

data Direction v n Source

A vector is described by a `Direction` and a magnitude. So we can think of a `Direction` as a vector that has forgotten its magnitude. `Direction`s can be used with `fromDirection` and the lenses provided by its instances.

Instances

Functor v => Functor (Direction v) Source |
HasPhi v => HasPhi (Direction v) Source |
HasTheta v => HasTheta (Direction v) Source |
Eq (v n) => Eq (Direction v n) Source |
Ord (v n) => Ord (Direction v n) Source |
Read (v n) => Read (Direction v n) Source |
Show (v n) => Show (Direction v n) Source |
((~) (* -> *) (V (v n)) v, (~) * (N (v n)) n, Transformable (v n)) => Transformable (Direction v n) Source |
type V (Direction v n) = v Source |
type N (Direction v n) = n Source |

_Dir :: Iso' (Direction v n) (v n) Source

_Dir is provided to allow efficient implementations of functions in particular vector-spaces, but should be used with care as it exposes too much information.

direction :: v n -> Direction v n Source

`direction v` is the direction in which `v` points. Returns an unspecified value when given the zero vector as input.

dir :: v n -> Direction v n Source

Synonym for `direction`.

fromDirection :: (Metric v, Floating n) => Direction v n -> v n Source

`fromDirection d` is the unit vector in the direction `d`.

fromDir :: (Metric v, Floating n) => Direction v n -> v n Source

Synonym for `fromDirection`.

angleBetweenDirs :: (Metric v, Floating n) => Direction v n -> Direction v n -> Angle n Source

compute the positive angle between the two directions in their common plane

dirBetween :: (Additive v, Num n) => Point v n -> Point v n -> Direction v n Source

`dirBetween p q` returns the directions from `p` to `q`