refactor(geom): update asSVG() bleed handling

BREAKING CHANGE: rename `bleed` attrib to `__bleed`

- for consistency, keep all control attribs prefixed as `__xxx`
- add asSvg() support for `__prec`
- update docs

packages/geom/src/as-svg.ts

@@ -10,7 +10,7 @@ import { __collBounds } from "./internal/bounds.js";
 /**
  * Can be overridden via {@link setSvgDefaultAttribs}.
  */
-let DEFAULT_ATTRIBS: Attribs = { fill: "none", stroke: "#000" };
+export let DEFAULT_ATTRIBS: Attribs = { fill: "none", stroke: "#000" };
 
 /**
  * Sets the SVG root element attribs used by default by {@link svgDoc}.
@@ -30,15 +30,28 @@ export const asSvg = (...args: any[]) =>
 	args.map((x) => serialize(convertTree(x))).join("");
 
 /**
- * Creates a hiccup SVG doc element for given {@link IShape}s and attribs
- * (merged with default attribs). If the attribs do not include a `viewBox`, it
- * will be computed automatically. Furthermore (and only for the case a viewbox
- * needs to be computed), a `bleed` attrib can be provided to include a
- * bleed/margin for the viewbox.
+ * Creates a hiccup SVG doc element container for given {@link IShape}s and
+ * attribs (merged with {@link DEFAULT_ATTRIBS}). If the attribs do not include
+ * a `viewBox`, it will be computed automatically. Furthermore (and only for the
+ * case a viewbox needs to be computed), a `__bleed` attrib can be provided to
+ * include a bleed/margin for the viewbox (in world space units).
  *
  * @remarks
  * Use {@link asSvg} to serialize the resulting doc to an SVG string.
  *
+ * The actual serialization is performed via the
+ * [thi.ng/hiccup](https://thi.ng/hiccup) and
+ * [thi.ng/hiccup-svg](https://thi.ng/hiccup-svg) packages. Floating point
+ * precision for various point coordinates can be controlled via the `__prec`
+ * attribute (number of fractional digits), either for the entire doc or on a
+ * per-shape basis. If omitted, the currently configured precision will be used
+ * (default: 3).
+ *
+ * Also see
+ * [`convertTree()`](https://docs.thi.ng/umbrella/hiccup-svg/functions/convertTree.html)
+ * and
+ * [`setPrecision()`](https://docs.thi.ng/umbrella/hiccup-svg/functions/setPrecision.html).
+ *
  * @param attribs
  * @param xs
  */
@@ -49,7 +62,7 @@ export const svgDoc = (attribs: Attribs, ...xs: IShape[]) => {
 			const cbounds = __collBounds(xs, bounds);
 			if (cbounds) {
 				const [[x, y], [w, h]] = cbounds;
-				const bleed = attribs.bleed || 0;
+				const bleed = attribs.__bleed || 0;
 				const bleed2 = 2 * bleed;
 				const width = ff(w + bleed2);
 				const height = ff(h + bleed2);
@@ -59,7 +72,7 @@ export const svgDoc = (attribs: Attribs, ...xs: IShape[]) => {
 					viewBox: `${ff(x - bleed)} ${ff(
 						y - bleed
 					)} ${width} ${height}`,
-					...withoutKeysObj(attribs, ["bleed"]),
+					...withoutKeysObj(attribs, ["__bleed"]),
 				};
 			}
 		}