Diagrams.Attributes

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.

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 where

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

colorToRGBA :: c -> (Double, Double, Double, Double)

Convert a color to red, green, blue, and alpha channels in the range [0,1].

Instances

Color FillColor

Color LineColor

Color SomeColor

(Floating a, Real a) => Color (Colour a)

(Floating a, Real a) => Color (AlphaColour a)

data SomeColor

An existential wrapper for instances of the Color class.

Constructors

forall c . Color c => SomeColor c

Instances

Typeable SomeColor

Color SomeColor

Line color

data LineColor

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

AttributeClass LineColor

Color LineColor

getLineColor :: LineColor -> SomeColor

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

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.

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

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

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

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

Fill color

data FillColor

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

AttributeClass FillColor

Color FillColor

getFillColor :: FillColor -> SomeColor

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

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 -> a

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 -> a

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

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

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

Opacity

data Opacity

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

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

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".

Lines

Width

data LineWidth

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

AttributeClass LineWidth

getLineWidth :: LineWidth -> Double

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

Set the line (stroke) width.

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

A convenient synonym for lineWidth.

Cap style

data LineCap

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

data LineCapA

Instances

Eq LineCapA

Typeable LineCapA

Semigroup LineCapA

AttributeClass LineCapA

getLineCap :: LineCapA -> LineCap

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

Set the line end cap attribute.

Join style

data LineJoin

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

data LineJoinA

Instances

Eq LineJoinA

Typeable LineJoinA

Semigroup LineJoinA

AttributeClass LineJoinA

getLineJoin :: LineJoinA -> LineJoin

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

Set the segment join style.

Dashing

data Dashing

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

Constructors

Dashing [Double] Double

Instances

Eq Dashing

Typeable Dashing

data DashingA

Instances

Eq DashingA

Typeable DashingA

Semigroup DashingA

AttributeClass DashingA

getDashing :: DashingA -> Dashing

dashing

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.