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Module Mlpost.Path


module Path: sig .. end
Fixed Paths

Paths are the objects used to describe lines, curves, and more generally almost everything that is drawn with Mlpost
type direction
A direction is used to put constraints on paths: 
val vec : Point.t -> direction
val curl : float -> direction
val noDir : direction
type knot
A knot is the basic element of a path, and is simply a point with an incoming and outgoing direction constraint
val knotp : ?l:direction ->
       ?r:direction -> Point.t -> knot
Build a knot from a point; the optional arguments are the incoming directions
val knotlist : (direction * Point.t * direction) list ->
       knot list
type joint
A joint is the connection between two knots in a path. It is either 
val jLine : joint
val jCurve : joint
val jCurveNoInflex : joint
val jTension : float -> float -> joint
val jControls : Point.t -> Point.t -> joint
type t
The abstract type of paths

In all the functions below :

Labelled path constructors


val knot : ?l:direction ->
       ?r:direction ->
       ?scale:(float -> Num.t) -> float * float -> knot
Build a knot from a pair of floats
l : an incoming direction
r : an outgoing direction
scale : a scaling factor applied to the floats
val knotn : ?l:direction ->
       ?r:direction -> Num.t * Num.t -> knot
Build a knot from a Num.t pair; the optional arguments are as in Path.knot
val path : ?style:joint ->
       ?cycle:joint ->
       ?scale:(float -> Num.t) -> (float * float) list -> t
Build a path from a list of pairs of floats
style : the joint style used for all joints in the path
cycle : if given, the path is closed using the given style
scale : permits to scale the whole path
val pathn : ?style:joint ->
       ?cycle:joint ->
       (Num.t * Num.t) list -> t
Same as path, but uses a Num.t list
val pathk : ?style:joint ->
       ?cycle:joint -> knot list -> t
Same as path, but uses a knot list
val pathp : ?style:joint ->
       ?cycle:joint -> Point.t list -> t
Same as path but uses a point list
val jointpathk : knot list -> joint list -> t
Build a path from n knots and n-1 joints
val jointpathp : Point.t list -> joint list -> t
Build a path from n points and n-1 joints, with default directions
val jointpathn : (Num.t * Num.t) list -> joint list -> t
val jointpath : ?scale:(float -> Num.t) ->
       (float * float) list -> joint list -> t
Build a path from n float_pairs and n-1 joints, with default directions
val cycle : ?dir:direction ->
       ?style:joint -> t -> t
Close a path using direction dir and style style

Primitive path constructors


val concat : ?style:joint ->
       t -> knot -> t
Add a knot at the end of a path
val start : knot -> t
Create a simple path with one knot
val append : ?style:joint -> t -> t -> t
Append a path to another using joint style

More complex constructions on paths


val length : t -> Num.t
Number of nodes in a path, minus one.
val point : float -> t -> Point.t
point f p returns a certain point on the path p; f is given "in control points": 0. means the first control point, 1. the second and so on; intermediate values are accepted.
val pointn : Num.t -> t -> Point.t
Same as point but for a Num.t.
val direction : float -> t -> Point.t
direction f p returns the direction of the tangent at point f p.
val directionn : Num.t -> t -> Point.t
Same as direction but for a Num.t.
val subpath : float -> float -> t -> t
subpath start end path selects the subpath of path that lies between start and end. start and end are given in control points, as in Path.point.
val subpathn : Num.t -> Num.t -> t -> t
Same as subpathn but using Num.t.
val transform : Transform.t -> t -> t
Apply a transformation to a path
val scale : Num.t -> t -> t
val rotate : float -> t -> t
val shift : Point.t -> t -> t
val yscale : Num.t -> t -> t
val xscale : Num.t -> t -> t
Shortcuts for transformations of Paths
val cut_after : t -> t -> t
cut_after p1 p2 cuts p2 after the intersection with p1. To memorize the order of the arguments, you can read: "cut after p1"
val cut_before : t -> t -> t
Same as Path.cut_after, but cuts before
val strip : Num.t -> t -> t
strip n p removes two segments of length n at each end of path p
val build_cycle : t list -> t
Build a cycle from a set of intersecting paths

Predefined values


val defaultjoint : joint
The default joint style (JCurve)
val fullcircle : t
A full circle of radius 1 and centered on the origin
val halfcircle : t
The upper half of fullcircle
val quartercircle : t
The right half of halfcircle
val unitsquare : t
A full square of size 1 and centered on the origin

Conversions


type metapath = MetaPath.t
Compute the control point of the path for a good looking result according to the constraint on the direction, tension, curve
val of_metapath : metapath -> t
val to_metapath : t -> metapath
Obtain a metapath from a path with exactly the same control point. p = of_metapath (of_path p) is true but not the opposite.

Smart path



type orientation =
| Up
| Down
| Left
| Right
| Upn of Num.t
| Downn of Num.t
| Leftn of Num.t
| Rightn of Num.t 
val smart_path : ?style:joint ->
       orientation list ->
       Point.t -> Point.t -> t
val draw : ?brush:Brush.t ->
       ?color:Color.t ->
       ?pen:Pen.t ->
       ?dashed:Dash.t -> t -> Command.t
Draw a path
brush : the brush used to draw the path; the next argument redefined this one
color : the color of the path; default is black
pen : the pen used to draw the path; default is Brush.Pen.default
dashed : if given, the path is drawn using that dash_style.
val fill : ?color:Color.t -> t -> Command.t
Fill a contour given by a closed path
color : the color used to fill the area; default is black