Maintainer	diagrams-discuss@googlegroups.com
Safe Haskell	None

Diagrams.Attributes

Contents

Color
Lines
Compilation utilities

Description

Diagrams may have attributes which affect the way they are rendered. This module defines some common attributes; particular backends may also define more backend-specific attributes.

Every attribute type must have a semigroup structure, that is, an associative binary operation for combining two attributes into one. Unless otherwise noted, all the attributes defined here use the Last structure, that is, combining two attributes simply keeps the second one and throws away the first. This means that child attributes always override parent attributes.

Synopsis

Color

Diagrams outsources all things color-related to Russell O'Connor's very nice colour package (http://hackage.haskell.org/package/colour). For starters, it provides a large collection of standard color names. However, it also provides a rich set of combinators for combining and manipulating colors; see its documentation for more information.

class Color c whereSource

The Color type class encompasses color representations which can be used by the Diagrams library. Instances are provided for both the Colour and AlphaColour types from the Data.Colour library.

Methods

toAlphaColour :: c -> AlphaColour Double Source

Convert a color to its standard representation, AlphaColour.

fromAlphaColour :: AlphaColour Double -> cSource

Convert from an AlphaColour Double. Note that this direction may lose some information. For example, the instance for Colour drops the alpha channel.

Instances

Color FillColor
Color LineColor
Color SomeColor
(Floating a, Real a) => Color (Colour a)
(Floating a, Real a) => Color (AlphaColour a)

data SomeColor Source

An existential wrapper for instances of the Color class.

Constructors

forall c . Color c => SomeColor c

Instances

Typeable SomeColor
Color SomeColor

someToAlpha :: SomeColor -> AlphaColour Double Source

Line color

data LineColor Source

The color with which lines (strokes) are drawn. Note that child colors always override parent colors; that is, lineColor c1 . lineColor c2 $ d is equivalent to lineColor c2 $ d. More precisely, the semigroup structure on line color attributes is that of Last.

Instances

Typeable LineColor
Semigroup LineColor
Default LineColor
AttributeClass LineColor
Color LineColor

getLineColor :: LineColor -> SomeColor Source

mkLineColor :: Color c => c -> LineColor Source

styleLineColor :: (Color c, Color c') => Setter (Style v) (Style v) c c'Source

lineColor :: (Color c, HasStyle a) => c -> a -> aSource

Set the line (stroke) color. This function is polymorphic in the color type (so it can be used with either Colour or AlphaColour), but this can sometimes create problems for type inference, so the lc and lcA variants are provided with more concrete types.

lineColorA :: HasStyle a => LineColor -> a -> aSource

Apply a lineColor attribute.

lc :: HasStyle a => Colour Double -> a -> aSource

A synonym for lineColor, specialized to Colour Double (i.e. opaque colors).

lcA :: HasStyle a => AlphaColour Double -> a -> aSource

A synonym for lineColor, specialized to AlphaColour Double (i.e. colors with transparency).

Fill color

data FillColor Source

The color with which shapes are filled. Note that child colors always override parent colors; that is, fillColor c1 . fillColor c2 $ d is equivalent to lineColor c2 $ d. More precisely, the semigroup structure on fill color attributes is that of Last.

Instances

Typeable FillColor
Semigroup FillColor
Default FillColor
AttributeClass FillColor
Color FillColor

getFillColor :: FillColor -> SomeColor Source

mkFillColor :: Color c => c -> FillColor Source

styleFillColor :: (Color c, Color c') => Setter (Style v) (Style v) c c'Source

recommendFillColor :: (Color c, HasStyle a) => c -> a -> aSource

Set a "recommended" fill color, to be used only if no explicit calls to fillColor (or fc, or fcA) are used.

fillColor :: (Color c, HasStyle a) => c -> a -> aSource

Set the fill color. This function is polymorphic in the color type (so it can be used with either Colour or AlphaColour), but this can sometimes create problems for type inference, so the fc and fcA variants are provided with more concrete types.

fc :: HasStyle a => Colour Double -> a -> aSource

A synonym for fillColor, specialized to Colour Double (i.e. opaque colors).

fcA :: HasStyle a => AlphaColour Double -> a -> aSource

A synonym for fillColor, specialized to AlphaColour Double (i.e. colors with transparency).

Opacity

data Opacity Source

Although the individual colors in a diagram can have transparency, the opacity/transparency of a diagram as a whole can be specified with the Opacity attribute. The opacity is a value between 1 (completely opaque, the default) and 0 (completely transparent). Opacity is multiplicative, that is, opacity o1 . opacity o2 === opacity (o1 * o2). In other words, for example, opacity 0.8 means "decrease this diagram's opacity to 80% of its previous opacity".

Instances

Typeable Opacity
Semigroup Opacity
AttributeClass Opacity

getOpacity :: Opacity -> Double Source

opacity :: HasStyle a => Double -> a -> aSource

Multiply the opacity (see Opacity) by the given value. For example, opacity 0.8 means "decrease this diagram's opacity to 80% of its previous opacity".

Converting colors

colorToSRGBA :: Color c => c -> (Double, Double, Double, Double)Source

Convert to sRGBA.

colorToRGBA :: Color c => c -> (Double, Double, Double, Double)Source

Deprecated: Renamed to colorToSRGBA.

Convert to sRGBA.

Lines

Width

data LineWidth Source

The width of lines. By default, the line width is measured with respect to the final coordinate system of a rendered diagram, as opposed to the local coordinate systems in effect at the time the line width was set for various subdiagrams. This is so that it is easy to combine a variety of shapes (some created by scaling) and have them all drawn using a consistent line width. However, sometimes it is desirable for scaling to affect line width; the freeze operation is provided for this purpose. The line width of frozen diagrams is affected by transformations.

Line widths specified on child nodes always override line widths specified at parent nodes.

Instances

Typeable LineWidth
Semigroup LineWidth
Default LineWidth
AttributeClass LineWidth

getLineWidth :: LineWidth -> Double Source

lineWidth :: HasStyle a => Double -> a -> aSource

Set the line (stroke) width.

lineWidthA :: HasStyle a => LineWidth -> a -> aSource

Apply a LineWidth attribute.

lw :: HasStyle a => Double -> a -> aSource

A convenient synonym for lineWidth.

Cap style

data LineCap Source

What sort of shape should be placed at the endpoints of lines?

Constructors

LineCapButt	Lines end precisely at their endpoints.
LineCapRound	Lines are capped with semicircles centered on endpoints.
LineCapSquare	Lines are capped with a squares centered on endpoints.

Instances

Eq LineCap
Show LineCap
Typeable LineCap
Default LineCap

data LineCapA Source

Instances

Eq LineCapA
Typeable LineCapA
Semigroup LineCapA
AttributeClass LineCapA

getLineCap :: LineCapA -> LineCap Source

lineCap :: HasStyle a => LineCap -> a -> aSource

Set the line end cap attribute.

Join style

data LineJoin Source

How should the join points between line segments be drawn?

Constructors

LineJoinMiter	Use a "miter" shape (whatever that is).
LineJoinRound	Use rounded join points.
LineJoinBevel	Use a "bevel" shape (whatever that is). Are these... carpentry terms?

Instances

Eq LineJoin
Show LineJoin
Typeable LineJoin
Default LineJoin

data LineJoinA Source

Instances

Eq LineJoinA
Typeable LineJoinA
Semigroup LineJoinA
AttributeClass LineJoinA

getLineJoin :: LineJoinA -> LineJoin Source

lineJoin :: HasStyle a => LineJoin -> a -> aSource

Set the segment join style.

Miter limit

newtype LineMiterLimit Source

Miter limit attribute affecting the LineJoinMiter joins. For some backends this value may have additional effects.

Constructors

LineMiterLimit (Last Double)

Instances

Typeable LineMiterLimit
Semigroup LineMiterLimit
Default LineMiterLimit
AttributeClass LineMiterLimit

getLineMiterLimit :: LineMiterLimit -> Double Source

lineMiterLimit :: HasStyle a => Double -> a -> aSource

Set the miter limit for joins with LineJoinMiter.

lineMiterLimitA :: HasStyle a => LineMiterLimit -> a -> aSource

Apply a LineMiterLimit attribute.

Dashing

data Dashing Source

Create lines that are dashing... er, dashed.

Constructors

Dashing [Double] Double

Instances

Eq Dashing
Typeable Dashing

data DashingA Source

Instances

Eq DashingA
Typeable DashingA
Semigroup DashingA
AttributeClass DashingA

getDashing :: DashingA -> Dashing Source

dashing Source

Arguments

:: HasStyle a
=> [Double]	A list specifying alternate lengths of on and off portions of the stroke. The empty list indicates no dashing.
-> Double	An offset into the dash pattern at which the stroke should start.
-> a
-> a

Set the line dashing style.

Compilation utilities

splitFills :: forall b v a. Typeable v => RTree b v a -> RTree b v aSource

Push fill attributes down until they are at the root of subtrees containing only loops. This makes life much easier for backends, which typically have a semantics where fill attributes are applied to linesnon-closed paths as well as loopsclosed paths, whereas in the semantics of diagrams, fill attributes only apply to loops.