thi-ng/umbrella

import type { NumOrString } from "@thi.ng/api";
import { convertTree } from "@thi.ng/hiccup-svg/convert";
import { ff } from "@thi.ng/hiccup-svg/format";
import { svg } from "@thi.ng/hiccup-svg/svg";
import { serialize } from "@thi.ng/hiccup/serialize";
import { withoutKeysObj } from "@thi.ng/object-utils/without-keys";
import type { Attribs, IShape } from "./api.js";
import { bounds } from "./bounds.js";
import { __collBounds } from "./internal/bounds.js";

export interface SVGDocAttribs extends Attribs {
    /**
     * SVG viewBox attribute. If not given, {@link svgDoc} will attempt to
     * compute the view box automatically, incl. optional
     * {@link SVGDocAttribs.__margin}.
     */
    viewBox: string;
    width: NumOrString;
    height: NumOrString;
    /**
     * Only used if no {@link SVGDocAttribs.viewBox} is given. Margin
     * width to add on all sides of the computed view box.
     *
     * @defaultValue 0
     */
    __margin: number;
}

/**
 * Default document attribs for {@link svgDoc} (minus XMLNS declarations). Can
 * be overridden via {@link setSvgDefaultAttribs}.
 */
export let SVG_DEFAULT_ATTRIBS: Partial<SVGDocAttribs> = {
    __prec: 3,
    fill: "none",
    stroke: "#000",
};

/**
 * Sets the SVG root element attribs used by default by {@link svgDoc}. If
 * `merge` is true, the given attribs will be merged with the existing ones
 * (rather than replacing completely).
 *
 * @param attribs
 * @param merge
 */
export const setSvgDefaultAttribs = (
    attribs: Partial<SVGDocAttribs>,
    merge = false
) => {
    SVG_DEFAULT_ATTRIBS = merge
        ? { ...SVG_DEFAULT_ATTRIBS, ...attribs }
        : attribs;
};

/**
 * Serializes given hiccup tree to an actual SVG source string.
 *
 * @param args
 */
export const asSvg = (...args: any[]) =>
    args.map((x) => serialize(convertTree(x))).join("");

/**
 * Creates a hiccup SVG doc element container for given {@link IShape}s and
 * attribs (merged with {@link SVG_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 `__margin` 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 shapes
 */
export const svgDoc = (
    attribs: Partial<SVGDocAttribs>,
    ...shapes: IShape[]
) => {
    let $attribs = { ...SVG_DEFAULT_ATTRIBS, ...attribs };
    if (shapes.length > 0) {
        if (!$attribs.viewBox) {
            const cbounds = __collBounds(shapes, bounds);
            if (cbounds) {
                const [[x, y], [w, h]] = cbounds;
                const margin = $attribs.__margin || 0;
                const width = ff(w + 2 * margin);
                const height = ff(h + 2 * margin);
                $attribs = {
                    width,
                    height,
                    viewBox: `${ff(x - margin)} ${ff(
                        y - margin
                    )} ${width} ${height}`,
                    ...withoutKeysObj($attribs, ["__margin"]),
                };
            }
        }
    }
    return svg($attribs, ...shapes);
};