1 files changed, 48 insertions, 0 deletions
diff --git a/client/src/layout.js b/client/src/layout.js
new file mode 100644
index 0000000..c9c2a4d
--- /dev/null
+++ b/client/src/layout.js
@@ -0,0 +1,48 @@
+import Viz from './viz.es';
+
+const toNumber = (i) => Number(i);
+const gv = new Viz({ workerURL: 'lib/lite.render.js' });
+
+export default class Layout {
+	constructor() {
+		this.src = 'digraph { node [shape="rectangle"];\n';
+	}
+
+	addNode(id, width, height) {
+		this.src += `  "${id}" [fixedsize=true; width=${width / 72}; height=${height / 72}];\n`;
+	}
+
+	addLink(from, to) {
+		this.src += `  "${from}" -> "${to}";\n`;
+	}
+
+	async render() {
+		this.src += '}';
+
+		const info = await gv.renderJSONObject(this.src, { format: 'json0' });
+		info.objects ||= [];
+		info.edges ||= [];
+		const [width, height] = info.bb.split(',').map(toNumber).slice(2);
+
+		const positions = {};
+		for (const object of info.objects) {
+			const [x, y] = object.pos.split(',').map(toNumber);
+			positions[object.name] = [ x, height - y ];
+		}
+
+		const links = info.edges.map((edge) => {
+			const pos = edge.pos.slice(2);
+			return pos.split(' ').map(p => {
+				const [x, y] = p.split(',');
+				return [toNumber(x), height - toNumber(y)];
+			});
+
+		});
+
+		return {
+			width, height,
+			positions,
+			links,
+		};
+	}
+}