Diagrams.TwoD.Arrow

Drawing arrows in two dimensions. For a tutorial on drawing arrows using this module, see the diagrams website: http://projects.haskell.org/diagrams/doc/arrow.html.

Examples

Example 1

-- Connecting two diagrams at their origins.

sq = square 2 # showOrigin # lc darkgray # lw 0.07
ds = (sq # named "left") ||| strutX 3 ||| (sq # named "right")

shaft  = cubicSpline False ( map p2 [(0, 0), (1, 0), (1, 0.2), (2, 0.2)])

example1 = ds # connect' (with & arrowHead .~ dart & headSize .~ 0.6
                               & tailSize .~ 0.5 & arrowTail .~ quill
                               & shaftStyle %~ lw 0.02 & arrowShaft .~ shaft)
                               "left" "right" # pad 1.1

Example 2

-- Comparing connect, connectPerim, and arrowAt.

oct  = octagon 1 # lc darkgray # lw 0.10 # showOrigin
dias = oct # named "first" ||| strut 3 ||| oct # named "second"

-- Connect two diagrams and two points on their trails.
ex12 = dias # connect "first" "second"
            # connectPerim "first" "second" (15/16 \@\@ turn) (9/16 \@\@ turn)

-- Place an arrow at (0,0) the size and direction of (0,1).
ex3 = arrowAt origin unit_Y

example2 = (ex12 <> ex3) # centerXY # pad 1.1

Creating arrows

arrowV :: Renderable (Path R2) b => R2 -> Diagram b R2

arrowV v creates an arrow with the direction and magnitude of the vector v (with its tail at the origin), using default parameters.

arrowV' :: Renderable (Path R2) b => ArrowOpts -> R2 -> Diagram b R2

arrowV' v creates an arrow with the direction and magnitude of the vector v (with its tail at the origin).

arrowAt :: Renderable (Path R2) b => P2 -> R2 -> Diagram b R2

Create an arrow starting at s with length and direction determined by the vector v.

arrowAt' :: Renderable (Path R2) b => ArrowOpts -> P2 -> R2 -> Diagram b R2

arrowBetween :: Renderable (Path R2) b => P2 -> P2 -> Diagram b R2

arrowBetween s e creates an arrow pointing from s to e with default parameters.

arrowBetween' :: Renderable (Path R2) b => ArrowOpts -> P2 -> P2 -> Diagram b R2

arrowBetween' opts s e creates an arrow pointing from s to e using the given options. In particular, it scales and rotates arrowShaft to go between s and e, taking head, tail, and gaps into account.

connect :: (Renderable (Path R2) b, IsName n1, IsName n2) => n1 -> n2 -> Diagram b R2 -> Diagram b R2

Connect two diagrams with a straight arrow.

connect' :: (Renderable (Path R2) b, IsName n1, IsName n2) => ArrowOpts -> n1 -> n2 -> Diagram b R2 -> Diagram b R2

Connect two diagrams with an arbitrary arrow.

connectPerim :: (Renderable (Path R2) b, IsName n1, IsName n2) => n1 -> n2 -> Angle -> Angle -> Diagram b R2 -> Diagram b R2

Connect two diagrams at point on the perimeter of the diagrams, choosen by angle.

connectPerim' :: (Renderable (Path R2) b, IsName n1, IsName n2) => ArrowOpts -> n1 -> n2 -> Angle -> Angle -> Diagram b R2 -> Diagram b R2

connectOutside :: (Renderable (Path R2) b, IsName n1, IsName n2) => n1 -> n2 -> Diagram b R2 -> Diagram b R2

Draw an arrow from diagram named "n1" to diagram named "n2". The arrow lies on the line between the centres of the diagrams, but is drawn so that it stops at the boundaries of the diagrams, using traces to find the intersection points.

connectOutside' :: (Renderable (Path R2) b, IsName n1, IsName n2) => ArrowOpts -> n1 -> n2 -> Diagram b R2 -> Diagram b R2

arrow :: Renderable (Path R2) b => Double -> Diagram b R2

arrow len creates an arrow of length len with default parameters, starting at the origin and ending at the point (len,0).

arrow' :: Renderable (Path R2) b => ArrowOpts -> Double -> Diagram b R2

arrow' opts len creates an arrow of length len using the given options, starting at the origin and ending at the point (len,0). In particular, it scales the given arrowShaft so that the entire arrow has length len.

Options

data ArrowOpts

Constructors

ArrowOpts

Fields

_arrowHead :: ArrowHT

_arrowTail :: ArrowHT

_arrowShaft :: Trail R2

_headSize :: Double

_tailSize :: Double

_headGap :: Double

_tailGap :: Double

_headStyle :: Style R2

_tailStyle :: Style R2

_shaftStyle :: Style R2

Instances

Default ArrowOpts

arrowHead :: Lens' ArrowOpts ArrowHT

A shape to place at the head of the arrow.

arrowTail :: Lens' ArrowOpts ArrowHT

A shape to place at the tail of the arrow.

arrowShaft :: Lens' ArrowOpts (Trail R2)

The trail to use for the arrow shaft.

headSize :: Lens' ArrowOpts Double

Radius of a circumcircle around the head.

tailSize :: Lens' ArrowOpts Double

Radius of a circumcircle around the tail.

headGap :: Lens' ArrowOpts Double

Distance to leave between the head and the target point.

tailGap :: Lens' ArrowOpts Double

Distance to leave between the starting point and the tail.

gap :: Traversal' ArrowOpts Double

headColor :: Color c => Setter' ArrowOpts c

A lens for setting or modifying the color of an arrowhead. For example, one may write ... (with & headColor .~ blue) to get an arrow with a blue head, or ... (with & headColor %~ blend 0.5 white) to make an arrow's head a lighter color. For more general control over the style of arrowheads, see headStyle.

Note that the most general type of headColor would be

  (Color c, Color c') => Setter ArrowOpts ArrowOpts c c'

but that can cause problems for type inference when setting the color. However, using it at that more general type may occasionally be useful, for example, if you want to apply some opacity to a color, as in ... (with & headColor %~ (`withOpacity` 0.5)). If you want the more general type, you can use headStyle . styleFillColor in place of headColor.

headStyle :: Lens' ArrowOpts (Style R2)

Style to apply to the head. headStyle is modified by using the lens combinator %~ to change the current style. For example, to change an opaque black arrowhead to translucent orange: (with & headStyle %~ fc orange . opacity 0.75).

tailColor :: Color c => Setter' ArrowOpts c

A lens for setting or modifying the color of an arrow tail. See headColor.

tailStyle :: Lens' ArrowOpts (Style R2)

Style to apply to the tail. See headStyle.

shaftColor :: Color c => Setter' ArrowOpts c

A lens for setting or modifying the color of an arrow shaft. See headColor.

shaftStyle :: Lens' ArrowOpts (Style R2)

Style to apply to the shaft. See headStyle.

straightShaft :: Trail R2

Straight line arrow shaft.

See Diagrams.TwoD.Arrowheads for a list of standard arrowheads and help creating your own.

module Diagrams.TwoD.Arrowheads