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|
open StdLabels
(** Common module for ensuring that the function is evaluated only once *)
(** This represent a single path, which can be transformed throug a [repr]
function. *)
module type PATH = sig
type t
(** Represent the path *)
val repr
: t -> (module Path.Repr.M
with type point = Path.Point.t
and type t = 's) -> 's -> 's
end
type printer =
[ `Fill
| `Line
| `Ductus ]
module type P = sig
include Path.Repr.M
type repr
val create_path
: (repr -> repr) -> t
val get
: t -> repr
end
module MakePrinter(M:Repr.ENGINE) : P
with type point = M.point
and type t = M.t
and type repr = M.repr = struct
type t = M.t
type point = M.point
type repr = M.repr
let get
: t -> repr
= M.get
let create_path
: (repr -> repr) -> t
= M.create_path
let start
: Path.Point.t -> t -> t
= fun pt t ->
M.start pt pt t
let line_to
: Path.Point.t -> Path.Point.t -> t -> t
= fun p0 p1 t ->
M.line_to
( p0
, p1 )
( Path.Point.copy p0 @@ Path.Point.get_coord' p0
, Path.Point.copy p1 @@ Path.Point.get_coord' p1 )
t
let quadratic_to
: (Path.Point.t * Gg.v2 * Gg.v2 * Path.Point.t) -> t -> t
= fun (p0, ctrl0, ctrl1, p1) t ->
let ctrl0' = Path.Point.get_coord' @@ Path.Point.copy p0 ctrl0
and ctrl1' = Path.Point.get_coord' @@ Path.Point.copy p1 ctrl1 in
M.quadratic_to
(p0, ctrl0, ctrl1, p1)
(Path.Point.copy p0 @@ Path.Point.get_coord' p0, ctrl0', ctrl1', Path.Point.copy p1 @@ Path.Point.get_coord' p1)
t
let stop = M.stop
end
(** Transform the two path, into a single one. *)
module ReprSingle = struct
type point = Path.Point.t
type repr =
| Move of (point)
| Line_to of (point * point)
| Quadratic of (point * Gg.v2 * Gg.v2 * point)
module R = struct
type t = repr list
type point = Path.Point.t
let start t actions =
(Move t)::actions
let line_to p0 p1 actions =
Line_to (p0, p1)::actions
let quadratic_to
: (point * Gg.v2 * Gg.v2 * point) -> t -> t
= fun q actions ->
(Quadratic q)::actions
let stop
: t -> t
= fun v -> v
end
let repr
: (module PATH with type t = 't) -> 't -> 't -> repr list * repr list
= fun (type t) (module P:PATH with type t = t) path back ->
let path = P.repr path (module R) []
and back = P.repr back (module R) [] in
path, back
end
(* Canva representation *)
module FillCanva = FillEngine.Make(CanvaPrinter)
module LineCanva = LineEngine.Make(CanvaPrinter)
module DuctusCanva = DuctusEngine.Make(CanvaPrinter)
(* SVG representation *)
module FillSVG = FillEngine.Make(Svg)
module DuctusSVG = DuctusEngine.Make(Svg)
(** Draw a path to a canva.contents
The code may seems scary, but is very repetitive. Firt, all points (from the
main stroke, and the interior one) are evaluated. Then, they are both rendered
using the selected engine.
*)
let to_canva
: (module PATH with type t = 's) -> 's * 's -> Brr_canvas.C2d.t -> printer -> unit
= fun (type s) (module R:PATH with type t = s) (path, back) ctx engine ->
let f, b = ReprSingle.repr (module R) path back in
match engine with
| `Fill ->
let t = List.fold_left2 f b
~init:(FillCanva.create_path (fun p -> Brr_canvas.C2d.fill ctx p; p))
~f:(fun ctx f b ->
match (f, b) with
| ReprSingle.Move p0, ReprSingle.Move p0' -> FillCanva.start p0 p0' ctx
| ReprSingle.Line_to l, ReprSingle.Line_to l' -> FillCanva.line_to l l' ctx
| ReprSingle.Quadratic q, ReprSingle.Quadratic q' -> FillCanva.quadratic_to q q' ctx
| _ -> ctx
) in
FillCanva.get t
|> Brr_canvas.C2d.stroke ctx
| `Line ->
let t = List.fold_left2 f b
~init:(LineCanva.create_path (fun p -> Brr_canvas.C2d.fill ctx p; p))
~f:(fun ctx f b ->
match (f, b) with
| ReprSingle.Move p0, ReprSingle.Move p0' -> LineCanva.start p0 p0' ctx
| ReprSingle.Line_to l, ReprSingle.Line_to l' -> LineCanva.line_to l l' ctx
| ReprSingle.Quadratic q, ReprSingle.Quadratic q' -> LineCanva.quadratic_to q q' ctx
| _ -> ctx
) in
LineCanva.get t
|> Brr_canvas.C2d.stroke ctx
| `Ductus ->
let t = List.fold_left2 f b
~init:(DuctusCanva.create_path (fun p -> Brr_canvas.C2d.fill ctx p; p))
~f:(fun ctx f b ->
match (f, b) with
| ReprSingle.Move p0, ReprSingle.Move p0' -> DuctusCanva.start p0 p0' ctx
| ReprSingle.Line_to l, ReprSingle.Line_to l' -> DuctusCanva.line_to l l' ctx
| ReprSingle.Quadratic q, ReprSingle.Quadratic q' -> DuctusCanva.quadratic_to q q' ctx
| _ -> ctx
) in
DuctusCanva.get t
|> Brr_canvas.C2d.stroke ctx
(** Draw a path and represent it as SVG *)
let to_svg
: (module PATH with type t = 's) -> color:Jstr.t -> 's * 's -> printer -> Brr.El.t
= fun (type s) (module R:PATH with type t = s) ~color (path, back) engine ->
let f, b = ReprSingle.repr (module R) path back in
match engine with
| `Fill ->
(* In order to deal with over crossing path, I cut the path in as
many segment as there is curve, and fill them all. Then, all of theme
are grouped inside a single element *)
let paths = ref [] in
let init = (FillSVG.create_path
(fun p ->
let repr = Svg.path
~at:Brr.At.[ v (Jstr.v "d") p ]
[] in
paths := repr::!paths;
Jstr.empty)) in
let _ = List.fold_left2 f b
~init
~f:(fun ctx f b ->
match (f, b) with
| ReprSingle.Move p0, ReprSingle.Move p0' -> FillSVG.start p0 p0' ctx
| ReprSingle.Line_to l, ReprSingle.Line_to l' -> FillSVG.line_to l l' ctx
| ReprSingle.Quadratic q, ReprSingle.Quadratic q' -> FillSVG.quadratic_to q q' ctx
| _ -> ctx
) in
Brr.El.v (Jstr.v "g")
~at:Brr.At.[
v (Jstr.v "fill") color
; v (Jstr.v "stroke") color]
!paths
| `Ductus ->
let init = DuctusSVG.create_path (fun _ -> Jstr.empty) in
let svg_path = List.fold_left2 f b
~init
~f:(fun ctx f b ->
match (f, b) with
| ReprSingle.Move p0, ReprSingle.Move p0' -> DuctusSVG.start p0 p0' ctx
| ReprSingle.Line_to l, ReprSingle.Line_to l' -> DuctusSVG.line_to l l' ctx
| ReprSingle.Quadratic q, ReprSingle.Quadratic q' -> DuctusSVG.quadratic_to q q' ctx
| _ -> ctx
)
|> DuctusSVG.get in
Svg.path
~at:Brr.At.[
v (Jstr.v "fill") color
; v (Jstr.v "stroke") color
; v (Jstr.v "d") svg_path ]
[]
| `Line ->
raise Not_found
|
