module MetaPath: sig .. end
MetaPaths: gradually build a path with constraints, get a real
path at thxe end.
MetaPaths are the objects used to describe lines, curves, and
more generally almost everything that is drawn with Mlpost.
A path (Path.t) is defined by points and control points.
A metapath is defined by points (knots) and constraints on the links
between the points. A metapath is an easy way to define a path gradually
with only a few points, and apply heuristics afterwards to transform it
into a real path (using of_metapath).
type Path.direction
A
direction is used to put constraints on metapaths:
vec p defines a direction by a point (interpreted as a vector)curl f changes the curling factor of the extremity of a metapath;
higher curling factor means flatter curvesnoDir means no particular direction
val vec : Point.t -> direction
val curl : float -> direction
val noDir : direction
type Path.knot
A knot is the basic element of a metapath, 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 Path.joint
A joint is the connection between two knots in a metapath. It is either
jLine for a straight linejCurve for a spline curvejCurveNoInflex to avoid inflexion pointsjTension f1 f2 to specify "tension" on the joint; jCurve uses a
default tension of 1. Higher tension means less "wild" curvesjControls p1 p2 to explicitely specify control points
val jLine : joint
val jCurve : joint
val jCurveNoInflex : joint
val jTension : float -> float -> joint
val jControls : Point.t -> Point.t -> joint
type
The abstract type of metapaths
type Path.t
In all the functions below :
- noDir is the default direction
- jCurve is the default joint
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
MetaPath.knot
val path : ?style:joint ->
?scale:(float -> Num.t) -> (float * float) list -> t
Build a metapath from a list of pairs of floats
style : the joint style used for all joints in the metapath
scale : permits to scale the whole metapath
val pathn : ?style:joint ->
(Num.t * Num.t) list -> t
Same as metapath, but uses a Num.t list
val pathk : ?style:joint ->
knot list -> t
Same as metapath, but uses a knot list
val pathp : ?style:joint -> Point.t list -> t
Same as metapath but uses a point list
val jointpathk : knot list -> joint list -> t
Build a metapath from n knots and n-1 joints
val jointpathp : Point.t list -> joint list -> t
Build a metapath 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 metapath from n float_pairs and n-1 joints,
with default directions
val cycle : ?dir:direction ->
?style:joint -> t -> path
Close a metapath using direction dir and style style
val concat : ?style:joint ->
t -> knot -> t
Add a knot at the end of a metapath
val start : knot -> t
Create a simple metapath with one knot
val append : ?style:joint ->
t -> t -> t
Append a metapath to another using joint style
Predefined values
val defaultjoint : joint
The default joint style (JCurve)
Conversions
val to_path : t -> path
Compute the control point of the path
for a good looking result according to the constraint
on the direction, tension, curve
val of_path : path -> t
Obtain a metapath from a path with exactly the same
control point. p = of_metapath (of_path p) is true but
not the opposite.