| Copyright | (c) 2011 diagrams-core team (see LICENSE) |
|---|---|
| License | BSD-style (see LICENSE) |
| Maintainer | diagrams-discuss@googlegroups.com |
| Safe Haskell | None |
| Language | Haskell2010 |
Diagrams.Core.HasOrigin
Description
Types which have an intrinsic notion of a "local origin", i.e. things which are not invariant under translation.
Documentation
class VectorSpace (V t) => HasOrigin t where Source
Class of types which have an intrinsic notion of a "local origin", i.e. things which are not invariant under translation, and which allow the origin to be moved.
One might wonder why not just use Transformable instead of
having a separate class for HasOrigin; indeed, for types which
are instances of both we should have the identity
moveOriginTo (origin .^+ v) === translate (negateV v)
The reason is that some things (e.g. vectors, Trails) are
transformable but are translationally invariant, i.e. have no
origin.
Methods
moveOriginTo :: Point (V t) -> t -> t Source
Move the local origin to another point.
Note that this function is in some sense dual to translate
(for types which are also Transformable); moving the origin
itself while leaving the object "fixed" is dual to fixing the
origin and translating the diagram.
Instances
| HasOrigin a => HasOrigin [a] | |
| (HasOrigin a, Ord a) => HasOrigin (Set a) | |
| VectorSpace v => HasOrigin (Point v) | |
| VectorSpace (V t) => HasOrigin (TransInv t) | |
| HasLinearMap v => HasOrigin (Transformation v) | |
| VectorSpace v => HasOrigin (Trace v) | |
| (InnerSpace v, Fractional (Scalar v)) => HasOrigin (Envelope v) | The local origin of an envelope is the point with respect to which bounding queries are made, i.e. the point from which the input vectors are taken to originate. |
| (HasOrigin a, HasOrigin b, (~) * (V a) (V b)) => HasOrigin (a, b) | |
| HasOrigin a => HasOrigin (Map k a) | |
| VectorSpace v => HasOrigin (Query v m) | |
| (OrderedField (Scalar v), InnerSpace v, HasLinearMap v) => HasOrigin (SubMap b v m) | |
| (HasLinearMap v, InnerSpace v, OrderedField (Scalar v)) => HasOrigin (Subdiagram b v m) | |
| (HasLinearMap v, InnerSpace v, OrderedField (Scalar v), Semigroup m) => HasOrigin (QDiagram b v m) | Every diagram has an intrinsic "local origin" which is the basis for all combining operations. |
moveOriginBy :: HasOrigin t => V t -> t -> t Source
Move the local origin by a relative vector.
moveTo :: HasOrigin t => Point (V t) -> t -> t Source
Translate the object by the translation that sends the origin to
the given point. Note that this is dual to moveOriginTo, i.e. we
should have
moveTo (origin .^+ v) === moveOriginTo (origin .^- v)
For types which are also Transformable, this is essentially the
same as translate, i.e.
moveTo (origin .^+ v) === translate v