hiccup-svg

@thi.ng/hiccup-svg

This project is part of the @thi.ng/umbrella monorepo.

About

SVG element functions for @thi.ng/hiccup & @thi.ng/hdom.

This package's functionality was formerly part of @thi.ng/hdom-components, but has been extracted to remain more focused.

Important

The functions provided here do produce valid hiccup elements, but since none of them make use of (or support) the global hiccup / hdom context object, they can ONLY be invoked directly, i.e. they MUST be called like:

// correct (direct invocation)
svg.svg(svg.circle([0, 0], 100, { fill: "red" }));

// incorrect / unsupported (lazy evaluation)
[svg.svg, [svg.circle, [0, 0], 100, { fill: "red" }]]

SVG conversion of hdom-canvas shape trees

Since v2.0.0 this package provides a conversion utility to translate the more compact syntax used for @thi.ng/hdom-canvas shape trees (designed for more performant realtime canvas drawing) into a SVG serializable hiccup format.

The convertTree() function takes a normalized hiccup tree of hdom-canvas shape definitions and recursively converts it into an hiccup flavor which is ready for SVG serialization. This conversion also involves translation & re-organization of various attributes. The function returns a new tree. The original remains untouched, as will any unrecognized tree/shape nodes (those will be transferred as-is to the result tree). See example below.

Installation

yarn add @thi.ng/hiccup-svg

Dependencies

• @thi.ng/hiccup

Usage examples

import * as svg from "@thi.ng/hiccup-svg";
import { serialize } from "@thi.ng/hiccup";
import * as fs from "fs";

fs.writeFileSync(
    "hello.svg",
    serialize(
        svg.svg(
            {width: 100, height: 100},
            svg.defs(svg.linearGradient("grad", 0, 0, 0, 1, [[0, "red"], [1, "blue"]])),
            svg.circle([50, 50], 50, {fill: "url(#grad)"}),
            svg.text("Hello", [50, 55], { fill: "white", "text-anchor": "middle"})
        )
    ));

Minimal example showing SVG conversion of a hdom-canvas scene:

// scene tree defined for hdom-canvas
const scene = [
    ["defs", {},
        ["radialGradient",
            { id: "bg", from: [150, 280], to: [150, 300], r1: 300, r2: 100 },
            [[0, "#07f"], [0.5, "#0ef"], [0.8, "#efe"], [1, "#af0"]]],
        ["radialGradient",
            { id: "sun", from: [110, 120], to: [110, 120], r1: 5, r2: 50 },
            [[0, "#fff"], [1, "rgba(255,255,192,0)"]]]
    ],
    ["circle", { fill: "$bg" }, [150, 150], 130],
    ["circle", { fill: "$sun" }, [110, 120], 50],
];

fs.writeFileSync(
    "radialgradient.svg",
    serialize(
        svg.svg({ width: 300, height: 300 }, svg.convertTree(scene))
    )
);

Result:

<svg version="1.1"
    xmlns="http://www.w3.org/2000/svg" 
    xmlns:xlink="http://www.w3.org/1999/xlink" width="300" height="300">
    <defs>
        <radialGradient id="bg" fx="150.00" fy="280.00" cx="150.00" cy="300.00" fr="300.00" r="100.00" gradientUnits="userSpaceOnUse">
            <stop offset="0" stop-color="#07f"/>
            <stop offset="0.5" stop-color="#0ef"/>
            <stop offset="0.8" stop-color="#efe"/>
            <stop offset="1" stop-color="#af0"/>
        </radialGradient>
        <radialGradient id="sun" fx="110.00" fy="120.00" cx="110.00" cy="120.00" fr="5.00" r="50.00" gradientUnits="userSpaceOnUse">
            <stop offset="0" stop-color="#fff"/>
            <stop offset="1" stop-color="rgb(255,255,192)" stop-opacity="0"/>
        </radialGradient>
    </defs>
    <circle cx="150.00" cy="150.00" r="130.00" fill="url(#bg)"/>
    <circle cx="110.00" cy="120.00" r="50.00" fill="url(#sun)"/>
</svg>

Authors

• Karsten Schmidt

License

© 2016 - 2018 Karsten Schmidt // Apache Software License 2.0