Library
Module
Module type
Parameter
Class
Class type
2d polygons made up of an outer, and zero or more inner Path2.t
s. Includes basic shape creation helpers, manipulations, (including offset and basic transformations), measurement, and validation.
type invalid = [
| `SelfIntersection of int
Raised during polygon validation if a path is found to self-intersect. The index refers to the culprit path (outer = 0
, with holes increasing).
| `CrossIntersection of int * int
Raised during polygon validation if two paths are found to intersect eachother. The indices refer to the paths in question (outer = 0
, with holes increasing).
| `DuplicatePoints
Raised during polygon validation if there are any duplicate points across all of the paths contained within t
.
]
type t = private {
outer : Path2.t;
outer perimeter
*)holes : Path2.t list;
inner paths to be subtracted from the outer shape
*)}
2-dimensional polygon
This type is kept private to force use of make
, which performs validation
by default, hopefully providing an early warning that the shape may have issues rendering in a CAD backend.
make ?validate ?holes outer
Create a 2d polygon from an outer
path (perimeter), and zero or more holes
(default = []
). If validate is true
(as it is by default), validation
is performed, raising exceptions if the defined polygon is not simple (and thus, may cause problems in CGAL).
add_holes ?validate ~holes t
Add holes
to t
. If validate is true
(as it is by default), validation
is performed, raising exceptions if the defined polygon is not simple (and thus, may cause problems in CGAL).
val validation : ?eps:float -> t -> unit
validation ?eps t
Validate that t
is a legal polygon, without self-intersections within paths, cross-intersections between paths, or any duplicate points. All checks are performed with the tolerance eps
. If valid, unit will be returned, otherwise an exception will be raised.
val is_simple : ?eps:float -> t -> bool
is_simple ?eps t
Return true
if t
is a simple polygon, without self-intersections within paths, cross-intersections between paths, or any duplicate points. All checks are performed with the tolerance eps
.
val circle : ?fn:int -> ?fa:float -> ?fs:float -> float -> t
circle ?fn ?fa ?fs r
Create a circle of radius r
.
val wedge :
?fn:int ->
?fa:float ->
?fs:float ->
centre:V2.t ->
radius:float ->
start:float ->
float ->
t
wedge ?fn ?fa ?fs ~centre ~radius ~start a
Create an arcing path (as in Path2.arc
), with the centre
point included to close the path, forming a wedge.
square ?center dims
Create a rectangular polygon with xy dims
(e.g. width and height). If center
is true
then the path will be centred around the origin (default = false
).
ellipse ?fn ?fa ?fs radii
Draw an ellipse with xy radii
. The greater of the two radii is used for fragment/resolution calculation.
val star : r1:float -> r2:float -> int -> t
star ~r1 ~r2 n
Draw an n
pointed star with inner radius r1
and outer radius r2
.
ring ?fn ?fa ?fs ~thickness radii
Draw an empty elliptical ring of outer xy radii
, with the given radial thickness
(difference between outer and inner radii). For a circular ring, use equal x and y radii.
box ?center ~thickness dims
Create a rectangular empty box of outer xy dimensions dims
, with the given xy thickness
(difference between outer and inner xy dimensions). If center
is true
, then the path will be centred around the origin (default = false
).
centroid ?eps t
Compute the centroid of the outer path of the polygon t
. If t.outer
is collinear or self-intersecting (within eps
tolerance), an Invalid_argument
exception is raised.
val area : ?signed:bool -> t -> float
area ?signed t
Compute the total area of the polygon t
. If signed
is true
, then the signed areas of the outer
and holes
paths of t
will be summed (keep in mind that this is dependent on winding direction, which should generally be opposite between outer and inner paths), otherwise the unsigned (positive) area of the holes
will be subtracted (default = false
).
val offset :
?fn:int ->
?fs:float ->
?fa:float ->
?check_valid:[ `Quality of int | `No ] ->
?mode:[< `Chamfer | `Delta | `Radius Delta ] ->
float ->
t ->
t
offset ?fn ?fs ?fa ?check_valid ?mode d t
Offset outer and inner paths of t
by the specified distance d
. The mode
governs how d
is used to create the new corners.
`Delta
will create a new outline whose sides are a fixed distance d
(+ve out, -ve in) from the original outline (this is the default behaviour).`Chamfer
fixed distance offset by d
as with delta, but with corners chamfered.`Radius
creates a new outline as if a circle of some radius d
is rotated around the exterior (d > 0
) or interior (d < 0
) original outline. fn
, fs
, and fa
parameters govern the number of points that will be used for these arcs (they are ignored for delta and chamfer modes).check_valid
default of `Quality 1
will check the validity of shifted line segments by checking whether their ends and n
additional points spaced throughout are far enough from the original path. If there are no points that have been offset by the target d
, a Failure
exception will be raised. Checking can be turned off by setting this to `No
.map f t
Map the outer and inner paths of t
with the function f
.