# diagrams-core

Core libraries for diagrams EDSL http://projects.haskell.org/diagrams

Version on this page: | 1.3.0.8 |

LTS Haskell 8.20: | 1.4 |

Stackage Nightly 2017-06-23: | 1.4 |

Latest on Hackage: | 1.4 |

**Brent Yorgey**

**diagrams-discuss@googlegroups.com**

#### Module documentation for 1.3.0.8

The core modules defining the basic data structures and algorithms for diagrams, a Haskell embedded domain-specific language for compositional, declarative drawing.

## Changes

## v1.4 (2016-10-26)

**New features**New

`eachName`

traversal, for traversing over parts of a`Name`

that match a given typeMore documentation explaining

`HasOrigin`

and`Transformable`

instances for`Envelope`

**Dependency/version changes**- Allow
`lens-4.15`

- Many other upper bounds bumped; see minor release changelogs below.

- Allow
**New instances**`Transformable`

instance for`Measured`

A bunch more instances for

`Query`

(`Distributive`

,`Representable`

,`Profunctor`

,`Coseive`

,`Closed`

,`Costrong`

,`Corepresentable`

)

**API changes**Move some

`Query`

-related functions to`diagrams-lib`

(`sample`

,`value`

,`resetValue`

,`clearValue`

)Remove some redundant constraints in type signatures (should not actually affect API)

## v1.3.0.8 (2016-06-05)

- allow
`base-4.9`

- build warning-free on GHC 8.0.1

## v1.3.0.7 (2016-05-01)

allow

`lens-4.14`

## v1.3.0.6 (2016-02-19)

allow

`unordered-containers-0.2.*`

## v1.3.0.5 (2016-01-14)

allow

`unordered-containers-0.2.6`

## v1.3.0.4 (2015-11-10)

allow

`semigroups-0.18`

## v1.3.0.3 (2015-09-17)

- allow
`lens-4.13`

- allow
`linear-1.20`

- allow
`semigroups-0.17`

## v1.3.0.2 (2015-07-19)

## v1.3.0.1 (2015-05-26)

## v1.3 (2015-04-19)

**New features**Update for ghc-7.10.

Switch from

`vector-space`

to`linear`

for linear algebra.`OpacityGroup`

annotation for setting the opacity of diagrams as a group. Opacity groups can be applied with the`opacityGroup`

or`groupOpacity`

functions.Added

`atAttr`

,`atMAttr`

and`atTAttr`

lenses onto the attributes of styles.`InSpace`

and`SameSpace`

synonyms.`size`

function for computing the range of an enveloped object in the basis vectors."Grouping" for transparent things #21

**Dependency/version changes**- Allow
`base-4.8`

- Allow
`lens-4.9`

- Allow
**New instances**`Show`

instances for`Attribute`

and`Style`

.`Each`

,`Ixed`

and`At`

instances for and`Style`

.

**API changes**`Measure`

has a new internal representation.`Local`

,`Global`

,`Normalized`

, and`Output`

have been renamed to`local`

,`global`

,`normalized`

and`output`

respectivly.`Measure`

is now defined in`Diagrams.Core.Measure`

.`GTAttribute`

has been removed.`MAttribute`

now holds measured attributes and no longer requires a`Data`

instance.`V`

is now a`* -> *`

kind type family.New type family

`N`

for the number type of an object,`Scalar`

type family no longer exists.`(|>)`

has moved to`(.>>)`

to make room for lens's snoc operator.`Style`

's internal representation now uses a hashmap of the`TypeRep`

.

**Merged pull requests:**

Bump lens upper version bounds #74 (RyanGlScott)

Add Diagram B synonym for Diagram b v n #73 (jeffreyrosenbluth)

Bump linear upper version bounds #75 (RyanGlScott)

Change Measure back to not using Scalar v #65 (Mathnerd314)

Remove gratuitous Data constraints #69 (Mathnerd314)

## v1.2.0.6 (2015-04-03)

**Closed issues:**

Please add support for recent versions of vector-space #78

## v1.2.0.5 (2015-01-13)

## v1.2.0.4 (2014-12-04)

## v1.2.0.3 (2014-11-17)

## v1.2.0.2 (2014-08-22)

**Closed issues:**

Warn against GND for IsName #67

## v1.2.0.1 (2014-06-04)

**Merged pull requests:**

## v1.2 (2014-06-02)

**New features**New function

`matrixHomRep`

to convert a transformation to a homogeneous matrix representation.New function

`dropTransl`

to drop the translation component from a transformation.A mini-DSL for Measures.

New

`extent`

function, used in`diameter`

.New

`dimension`

function to return the dimension of a vector space.New

`_relative`

iso between points and vectors.`avgScale`

function (for computing the average scaling factor of a transformation) has been moved from`diagrams-lib`

to`diagrams-core`

and generalized to work over any vector space.

**Dependency/version changes**- Allow
`semigroups-0.15`

- Allow
`lens-4.2`

- Allow
**API changes**Major refactoring which removes

`freeze`

(and hence`Split`

transforms, etc.) and adds units of`Measure`

.Refactoring and simplification of the

`Backend`

class.Remove

`Multibackend`

.Remove

`nullPrim`

,`IsPrim`

and simplify`RPrim`

so that it does not carry a transformation.Update

`adjustDia`

to return a transformation, not just a scale factor. Add`renderDiaT`

which returns a transformation (for use by end users, e.g. to convert output coordinates back into local coordinates).

**Implemented enhancements:**

Extracting things from Prim wrappers #42

**Closed issues:**

**Merged pull requests:**

Clean-slate redesign/simplification of

`Backend`

class #60 (byorgey)Avg scale #58 (jeffreyrosenbluth)

Preliminary implementation of Measure #55 (jeffreyrosenbluth)

No mco #62 (jeffreyrosenbluth)

## v1.1 (2014-03-09)

**New features**- New
`basis`

function - New
`determinant`

function for computing the determinant of a`Transformation`

- Add
`Typeable`

constraint on`Prim`

s, making it possible to extract things back out of a`Prim`

wrapper using`cast`

- Raw
`Trace`

s now return a*sorted list*of intersections, instead of only the smallest. This is used to implement a new family of functions`rayTraceV`

,`rayTraceP`

,`maxRayTraceV`

,`maxRayTraceP`

, which work similarly to the parallel versions without`Ray`

, but return the first intersection in the*positive*direction from the given point, rather than the smallest in absolute terms. - New
`Annotation`

type and corresponding`applyAnnotation`

function, for attaching uninterpreted annotations at specific points in a diagram tree. Currently this is used for hyperlinks; more annotation types will be added in the future.

- New
**Dependency/version changes**- Require
`lens-4.0`

- Allow
`vector-space-points-0.2`

- Require
**Bug fixes**- Looking up a subdiagram by name now results in a diagram which still has that name (#43)

**Closed issues:**

Named subdiagrams lose their names after being looked up #43

**Merged pull requests:**

Added

`basis`

, simplified`onBasis`

#54 (jeffreyrosenbluth)Determinants #53 (jeffreyrosenbluth)

Introduce Typeable constraint on Prims (see #42) #52 (byorgey)

return list of traces #48 (jeffreyrosenbluth)

## v1.0.0.1 (2013-11-28)

## v1.0 (2013-11-25)

**New features**Delayed subtrees: instead of a primitive, one can now also have a delayed subtree at a leaf, containing a continuation which generates a

`QDiagram`

when given the accumulated d-annotation at that point in the tree. Useful for things which need to know the final transformation applied to them before deciding what diagram to generate. The prototypical use case is arrows: see https://github.com/diagrams/diagrams-lib/issues/112 . However, this may be useful for other things as well: for example, diagrams which scale normally until hitting some maximum or minimum size, at which point they refuse to scale any further (or more generally diagrams which scale as some non-linear function of the transformation applied to them).The only downside is that the u-annotation must be fixed ahead of time---doing otherwise requires a more general solution for constraint solving.

New function

`lookupName`

for doing a simple lookup of a named subdiagramNew module

`Diagrams.Core.Compile`

, containing a framework for compiling`QDiagrams`

into a simpler tree type`RTree`

, which may be used by backends for rendering.

**New instances**`Qualifiable`

instances for`(,)`

,`(,,)`

,`[]`

,`Set`

,`Map k`

, and`(->) e`

.`(->) e`

instance for`Juxtaposable`

(thanks to Carlos Scheidegger)

**API changes**Export

`pointDiagram`

function, which creates an otherwise empty diagram with a point (not empty) envelope- A bunch of stuff now uses machinery from the
`lens`

library.`envelope`

,`trace`

, and`subMap`

are now`Lens'`

es`Wrapped`

instances for`Trace`

,`TransInv`

,`QDiagram`

,`SubMap`

,`Envelope`

,`Style`

,`Query`

, and`Name`

(replaces`Newtype`

instances)`Iso`

s for`Query`

,`Envelope`

,`QDiagram`

,`SubMap`

,`TransInv`

**Implemented enhancements:**

Tree structure in Backends #19

**Merged pull requests:**

Lens #44 (jeffreyrosenbluth)

## v0.7.0.1 (2013-09-27)

**Merged pull requests:**

## v0.7 (2013-08-09)

**New features**- new function
`onBasis`

, to extract the matrix equivalent of a`Transformation`

`SubMap`

s are now`Deletable`

- new function
`localize`

for hiding/deleting names from scope - new
`IsPrim`

class, containing`transformWithFreeze`

function. This is primarily intended to support scale-invariant primitives (*e.g.*arrowheads) but may be useful for other stuff as well.

The default implementation of

`renderDia`

now uses`transformWithFreeze`

. - optimized`Transformable`

instance for`TransInv`

- new function
**New instances**`Eq`

,`Ord`

,`Enveloped`

,`Traced`

, and`Qualifiable`

instances for`TransInv`

`Transformable`

instance for functions, which acts by conjugation

**API changes**`named`

and`namePoint`

have moved to the`diagrams-lib`

package.

**Dependency/version changes**- allow
`base-4.7`

- upgrade to
`monoid-extras-0.3`

- allow

**Implemented enhancements:**

Function to extract matrix coefficients from a Transformation #22

**Closed issues:**

Support for monoid-extras-0.3.0.0 #38

**Merged pull requests:**

## v0.6.0.2 (2013-03-06)

**Fixed bugs:**

radius is wrong #35

**Merged pull requests:**

## v0.6.0.1 (2013-01-07)

**Fixed bugs:**

"type instance V (Point v) = v" is not visible without explicit import. #17

**Merged pull requests:**

## v0.6 (2012-12-12)

**New features**Proper support for subdiagrams: previous versions of diagrams-core had a mechanism for associating names with a pair of a location and an envelope. Now, names are associated with actual subdiagrams (including their location and envelope, along with all the other information stored by a diagram).

See

`Diagrams.Core.Types`

.Traces: in addition to an envelope, each diagram now stores a "trace", which is like an embedded raytracer: given any ray (represented by a base point and a vector), the trace computes the closest point of intersection with the diagram along the ray. This is useful for determining points on the boundary of a diagram,

*e.g.*when drawing arrows between diagrams.See

`Diagrams.Core.Trace`

.

**API changes**The modules have all been renamed to be more consistent with the module naming scheme in the rest of the diagrams universe. In particular:

`Graphics.Rendering.Diagrams`

-->`Diagrams.Core`

`Grahpics.Rendering.Diagrams.Core`

-->`Diagrams.Core.Types`

`Graphics.Rendering.Diagrams.*`

-->`Diagrams.Core.*`

`Graphics.Rendering.Diagrams.UDTree`

has been split out into a separate`dual-tree`

package (which has also been substantially rewritten).`Graphics.Rendering.Diagrams.{Monoids,MList}`

have been split out into a separate`monoid-extras`

package.The

`names`

function now returns a list of names and their associated locations, instead of the associated subdiagrams. In particular the output is suitable to be rendered to a`String`

using`show`

.The new

`subMap`

function fills a similar role that`names`

used to play, returning the entire mapping from names to subdiagrams.New functions

`envelope[VP]May`

`envelopeV`

and`envelopeP`

return the zero vector and origin, respectively, when called on an empty envelope. However, sometimes it's useful to actually know whether the envelope was empty or not (the zero vector and the origin are legitimate outputs from non-empty envelopes). The new functions have their return type wrapped in`Maybe`

for this purpose.New functions

`envelopeS`

and`envelopeSMay`

Like

`envelope[VP](May)`

, but returning a scalar multiple of the input vector.The

`Graphics.Rendering.Diagrams.Util`

module has been removed, along with the`withLength`

function. Calls to`withLength`

can be replaced using`withLength s v = s *^ normalized v`

Add needed constraints

`(InnerSpace v, OrderedField (Scalar v), Monoid' m)`

to the type of the`renderDias`

method in the`MultiBackend`

class.Generalized

`Transformable`

instances for pairs and tuplesPreviously, the components of the tuples were required to have the same type; but everything still works as long as they all share the same vector space. This is actually useful in practice: say, if we wanted to pair a diagram with a path and then apply the same transformation to both.

**Improvements**- More efficient implementation of
`diameter`

- More efficient implementation of
**Dependency/version changes**- Tested with GHC 7.6.1
- allow
`base-4.6`

- allow
`containers-0.5.*`

- allow
`MemoTrie-0.6.1`

**Bug fixes**juxtaposeDefault now correctly handles empty envelopes (#37)

`juxtaposeDefault`

is now the identity on the second object if either one has an empty envelope. In particular this means that`mempty`

is now an identity element for`beside`

and friends.

**Implemented enhancements:**

Turn R2 into D2 (Generalize R2 to any numeric type) #20

Terminology: rename "bounding function" -> "envelope"; "boundary function" -> "boundary" #16

Refactor: rename AnnDiagram to QDiagram #15

Combine (point, bounds) pairs stored in NameMap into a single "located bounding function" data structure #14

Remember more structure when building diagrams #12

Diagram-building service library + executable #7

**Fixed bugs:**

setBounds is incorrect -- throws away bounds of subsequent diagrams too #13

Start developing test suites #10

Freezing does not appear to work with the SVG backend #9

Silent failure on other image types than .png #6

Tutorial contains links to old version of package #5

space is not left for empty diagram when using e.g. hcat' with {sep = ... } #3

Ellipse rotated incorrectly in test file with ellipse next to a square #2

**Closed issues:**

Rename core modules to remove Graphics.Rendering prefix. #28

Improve haddock documentation #11

Improve description of Envelope in Haddock documentation #1

**Merged pull requests:**

Add envelopeS / envelopeSMay for querying scalar displacements from envelopes #31 (mgsloan)

Rename

`names`

to`subMap`

, and add new function`names`

#26 (byorgey)Fix for juxtaposeDefault to correctly handle empty envelopes #24 (byorgey)

## v0.5 (2012-03-09)

- New features:
- New
`Juxtaposable`

class - New
`NullBackend`

and`D`

types, for conveniently giving a monomorphic type to diagrams when we don't care which one it is. - #27: Change type of
`adjustDia`

to return a new options record (with an explicitly filled-in size)

- New
- New instances:
`Enveloped`

,`HasOrigin`

,`Juxtaposable`

,`HasStyle`

, and`Transformable`

instances for`Set`

s and tuples`V Double = Double`

`Juxtaposable`

and`Boundable`

instances for`Map`

- API changes
`AnnDiagram`

renamed to`QDiagram`

- #61: terminology change from "bounds" to "envelope"
`boundary`

->`envelopeP`

- "bounding region" -> "envelope"
`Bounds`

->`Envelope`

`Boundable`

->`Enveloped`

`getBounds`

->`getEnvelope`

*etc.*

- Split out definition of
`Point`

into separate package (`vector-space-points`

) - The
`Point`

constructor`P`

is no longer exported from`Graphics.Rendering.Diagrams`

. See the`Diagrams.TwoD.Types`

module from`diagrams-lib`

for new tools for working with abstract 2D points. If you really need the`P`

constructor, import`Graphics.Rendering.Diagrams.Points`

. - Name-related functions now return "located bounding functions" instead of pairs of points and bounds, to allow for future expansion.

- Dependency/version changes:
`vector-space`

0.8 is now required.- Bump base upper bound to allow 4.5; now tested with GHC 7.4.1.

- Bug fixes:
- Bug fix related to empty envelopes

## 0.4: 23 October 2011

- improved documentation
- a few new instances (Newtype Point, Boundable Point)
- new functions (value, clearValue, resetValue) for working with alternate query monoids

## 0.3: 18 June 2011

- big overhaul of name maps:
- allow arbitrary types as atomic names
- carry along bounding functions as well as names in NameMaps
- additional functions for querying information associated with names

- fix for issue #34 (fix behavior of setBounds)
- Transformable and HasOrigin instances for Transformations

## 0.2: 3 June 2011

- bounding regions can now be overridden
- new namePoint function for more flexibly assigning names to arbitrary points
- add HasStyle, Boundable, and HasOrigin instances for lists
- add a "trivial backend"
- transformable attributes

## 0.1.1: 18 May 2011

link to new website

## 0.1: 17 May 2011

initial preview release

* *This Change Log was automatically generated by (and hand edited) github changeloggenerator*