feat(geom): add asCubic() impls for circle, group, rect

- re-use arc impl from geom-splines
thi-ng · Jul 12, 2019 · 5ca4166 · 5ca4166
1 parent 3e386f7
commit 5ca4166
Showing 1 changed file with 21 additions and 57 deletions.
diff --git a/packages/geom/src/ops/as-cubic.ts b/packages/geom/src/ops/as-cubic.ts
@@ -1,80 +1,42 @@
 import { IObjectOf } from "@thi.ng/api";
 import { defmulti, Implementation1, MultiFn1O } from "@thi.ng/defmulti";
 import { CubicOpts, IShape, Type } from "@thi.ng/geom-api";
-import { closedCubicFromBreakPoints, closedCubicFromControlPoints } from "@thi.ng/geom-splines";
-import {
-    EPS,
-    HALF_PI,
-    roundEps,
-    sincos
-} from "@thi.ng/math";
+import { closedCubicFromBreakPoints, closedCubicFromControlPoints, cubicFromArc } from "@thi.ng/geom-splines";
+import { TAU } from "@thi.ng/math";
 import { mapcat } from "@thi.ng/transducers";
-import { add2, magSq2 } from "@thi.ng/vectors";
 import {
     Arc,
+    Circle,
     Cubic,
+    Group,
     Line,
     Path,
     Polygon,
-    Quadratic
+    Quadratic,
+    Rect
 } from "../api";
-import { cubic, cubicFromLine, cubicFromQuadratic } from "../ctors/cubic";
+import { arc } from "../ctors/arc";
+import { cubicFromLine, cubicFromQuadratic } from "../ctors/cubic";
 import { dispatch } from "../internal/dispatch";
+import { asPolygon } from "./as-polygon";
 
 export const asCubic: MultiFn1O<IShape, Partial<CubicOpts>, Cubic[]> = defmulti(
     dispatch
 );
 
 asCubic.addAll(<IObjectOf<Implementation1<unknown, Cubic[]>>>{
-    [Type.ARC]: ($: Arc) => {
-        const p = $.pointAtTheta($.start);
-        const q = $.pointAtTheta($.end);
-        const [rx, ry] = $.r;
-        const [sphi, cphi] = sincos($.axis);
-        const dx = (cphi * (p[0] - q[0])) / 2 + (sphi * (p[1] - q[1])) / 2;
-        const dy = (-sphi * (p[0] - q[0])) / 2 + (cphi * (p[1] - q[1])) / 2;
-        if ((dx === 0 && dy === 0) || magSq2($.r) < EPS) {
-            return [cubicFromLine(p, q, { ...$.attribs })];
-        }
-
-        const mapP = (x: number, y: number) => {
-            x *= rx;
-            y *= ry;
-            return add2(
-                null,
-                [cphi * x - sphi * y, sphi * x + cphi * y],
-                $.pos
-            );
-        };
+    [Type.ARC]: ($: Arc) =>
+        cubicFromArc($.pos, $.r, $.axis, $.start, $.end).map(
+            (c) => new Cubic(c, $.attribs)
+        ),
 
-        const res: Cubic[] = [];
-        const delta = $.end - $.start;
-        const n = Math.max(roundEps(Math.abs(delta) / HALF_PI, 1e-3), 1);
-        // https://github.com/chromium/chromium/blob/master/third_party/blink/renderer/core/svg/svg_path_parser.cc#L253
-        const d = delta / n;
-        const t = (8 / 6) * Math.tan(0.25 * d);
-        if (!isFinite(t)) {
-            return [cubicFromLine(p, q)];
-        }
-        for (let i = n, theta = $.start; i > 0; i--, theta += d) {
-            const [s1, c1] = sincos(theta);
-            const [s2, c2] = sincos(theta + d);
-            const curve = new Cubic(
-                [
-                    mapP(c1, s1),
-                    mapP(c1 - s1 * t, s1 + c1 * t),
-                    mapP(c2 + s2 * t, s2 - c2 * t),
-                    mapP(c2, s2)
-                ],
-                { ...$.attribs }
-            );
-            res.push(curve);
-        }
-        return res;
-    },
+    [Type.CIRCLE]: ($: Circle) =>
+        asCubic(arc($.pos, $.r, 0, 0, TAU, true, true)),
 
     [Type.CUBIC]: ($: Cubic) => [$],
 
+    [Type.GROUP]: ($: Group) => [...mapcat(asCubic, $.children)],
+
     [Type.LINE]: ({ attribs, points }: Line) => [
         cubicFromLine(points[0], points[1], { ...attribs })
     ],
@@ -88,10 +50,12 @@ asCubic.addAll(<IObjectOf<Implementation1<unknown, Cubic[]>>>{
         return (opts.breakPoints
             ? closedCubicFromBreakPoints($.points, opts.scale, opts.uniform)
             : closedCubicFromControlPoints($.points, opts.scale, opts.uniform)
-        ).map((pts) => cubic(pts, { ...$.attribs }));
+        ).map((pts) => new Cubic(pts, { ...$.attribs }));
     },
 
     [Type.QUADRATIC]: ({ attribs, points }: Quadratic) => [
         cubicFromQuadratic(points[0], points[1], points[2], { ...attribs })
-    ]
+    ],
+
+    [Type.RECT]: ($: Rect, opts?) => asCubic(asPolygon($), opts)
 });