feat(geom): add PathBuilderOpts, update Path.toHiccup()

- add support to disable auto-splitting paths in PathBuilder - update toHiccup() impl to support multiple `M` cmds
thi-ng · Jul 13, 2020 · deb9892 · deb9892
1 parent ad72de3
commit deb9892
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Showing 2 changed files with 34 additions and 16 deletions.
diff --git a/packages/geom/src/api/path.ts b/packages/geom/src/api/path.ts
@@ -5,15 +5,12 @@ import { copyAttribs } from "../internal/copy-attribs";
 import { copy } from "@thi.ng/vectors";
 
 export class Path implements IHiccupShape {
-    segments: PathSegment[];
-    closed: boolean;
-    attribs?: Attribs;
+    closed = false;
 
-    constructor(segments?: PathSegment[], attribs?: Attribs) {
-        this.segments = segments || [];
-        this.attribs = attribs;
-        this.closed = false;
-    }
+    constructor(
+        public segments: PathSegment[] = [],
+        public attribs?: Attribs
+    ) {}
 
     get type() {
         return Type.PATH;
@@ -51,9 +48,13 @@ export class Path implements IHiccupShape {
         const segments = this.segments;
         const n = segments.length;
         if (n > 1) {
-            dest.push(["M", segments[0].point]);
-            for (let i = 1; i < n; i++) {
-                dest = dest.concat(segments[i].geo!.toHiccupPathSegments());
+            for (let i = 0; i < n; i++) {
+                const s = segments[i];
+                if (s.geo) {
+                    dest = dest.concat(s.geo!.toHiccupPathSegments());
+                } else if (s.point) {
+                    dest.push(["M", s.point]);
+                }
             }
             if (this.closed) {
                 dest.push(["Z"]);

diff --git a/packages/geom/src/ctors/path-builder.ts b/packages/geom/src/ctors/path-builder.ts
@@ -8,15 +8,29 @@ import { Path } from "../api/path";
 import { Quadratic } from "../api/quadratic";
 import { arcFrom2Points } from "./arc";
 
+export interface PathBuilderOpts {
+    /**
+     * If true (default), "move" commands will start a new path and
+     * {@link PathBuilder} might produce multiple {@link Path}s. In general,
+     * it's NOT recommended to disable this behavior since various path related
+     * operations will not function properly anymore. However, there're some use
+     * cases where auto-splitting is undesirable and this option primarily
+     * exists for those.
+     */
+    autoSplit: boolean;
+}
+
 export class PathBuilder {
     paths: Path[];
-    attribs?: Attribs;
     protected curr!: Path;
     protected currP!: Vec;
     protected bezierP!: Vec;
     protected startP!: Vec;
 
-    constructor(attribs?: Attribs) {
+    constructor(
+        public attribs?: Attribs,
+        public opts: Partial<PathBuilderOpts> = {}
+    ) {
         this.paths = [];
         this.attribs = attribs;
         this.newPath();
@@ -39,8 +53,8 @@ export class PathBuilder {
     }
 
     moveTo(p: Vec, relative = false): PathBuilder {
-        if (this.curr.segments.length > 0) {
-            this.curr = new Path();
+        if (this.opts.autoSplit !== false && this.curr.segments.length > 0) {
+            this.curr = new Path([], this.attribs);
             this.paths.push(this.curr);
         }
         p = this.updateCurrent(p, relative);
@@ -184,4 +198,7 @@ export class PathBuilder {
     }
 }
 
-export const pathBuilder = (attribs?: Attribs) => new PathBuilder(attribs);
+export const pathBuilder = (
+    attribs?: Attribs,
+    opts?: Partial<PathBuilderOpts>
+) => new PathBuilder(attribs, opts);