98 lines
2.4 KiB
TypeScript
98 lines
2.4 KiB
TypeScript
import maplibregl from "maplibre-gl";
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import { Geometry } from "@/lib/useEditorState";
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type ModeGetter = () => "idle" | "draw" | "select" | "add-point";
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export function initDrawing(
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map: maplibregl.Map,
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getMode: ModeGetter,
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onComplete: (geometry: Geometry) => void
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) {
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let coords: [number, number][] = [];
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/**
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* Close polygon ring if not closed.
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*/
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function closePolygon(c: [number, number][]) {
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if (c.length < 3) return c;
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const first = c[0];
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const last = c[c.length - 1];
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if (first[0] !== last[0] || first[1] !== last[1]) {
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return [...c, first];
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}
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return c;
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}
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/**
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* Update preview layer while drawing.
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*/
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function update(c: [number, number][]) {
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const closed = closePolygon(c);
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(map.getSource("draw-preview") as maplibregl.GeoJSONSource)?.setData({
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type: "FeatureCollection",
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features: [
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{
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type: "Feature",
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geometry: {
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type: "Polygon",
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coordinates: [closed],
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},
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},
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],
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});
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}
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function onClick(e: maplibregl.MapLayerMouseEvent) {
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if (getMode() !== "draw") return;
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coords.push([e.lngLat.lng, e.lngLat.lat]);
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update(coords);
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}
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function onMove(e: maplibregl.MapLayerMouseEvent) {
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if (getMode() !== "draw" || coords.length === 0) return;
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const preview = [...coords, [e.lngLat.lng, e.lngLat.lat]];
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update(preview);
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}
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/**
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* Finalize polygon, emit geometry to caller, reset preview.
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*/
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function finishDrawing() {
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if (getMode() !== "draw" || coords.length < 3) return;
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const geometry = {
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type: "Polygon",
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coordinates: [closePolygon(coords)],
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};
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onComplete(geometry);
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coords = [];
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map.getSource("draw-preview").setData({
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type: "FeatureCollection",
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features: [],
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});
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}
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function onKeyDown(e: KeyboardEvent) {
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if (e.key === "Enter") {
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finishDrawing();
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}
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}
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map.on("click", onClick);
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map.on("mousemove", onMove);
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document.addEventListener("keydown", onKeyDown);
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return () => {
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map.off("click", onClick);
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map.off("mousemove", onMove);
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document.removeEventListener("keydown", onKeyDown);
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};
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}
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