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fix: display snaps on first render if zoom within threshold #112

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Merged
jessicamcinchak merged 1 commit into from
Feb 4, 2022
Merged

fix: display snaps on first render if zoom within threshold #112

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2 changes: 1 addition & 1 deletion index.html
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@
/>
</head>
<body>
<my-map zoom="18" maxZoom="23" drawMode drawPointer="dot" id="example-map" />
<my-map zoom="20" maxZoom="23" drawMode drawPointer="dot" id="example-map" />

<script>
const map = document.querySelector("my-map");
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20 changes: 16 additions & 4 deletions src/my-map.ts
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Expand Up @@ -381,23 +381,35 @@ export class MyMap extends LitElement {
});
}

// show snapping points when in drawMode, with vector tile basemap enabled, and at zoom > 20
// show snapping points when in drawMode, with vector tile basemap enabled, and at qualifying zoom
if (
this.drawMode &&
Boolean(this.osVectorTilesApiKey) &&
!this.disableVectorTiles
) {
// define zoom threshold for showing snaps (not @property yet because computationally expensive!)
const snapsZoom: number = 20;
Comment on lines +390 to +391
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@DafyddLlyr DafyddLlyr Feb 4, 2022

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I agree that making this accessible would be a bad idea!


// display draw vertices on top of snap points
map.addLayer(pointsLayer);
drawingLayer.setZIndex(1001); // display draw vertices on top of snap points
drawingLayer.setZIndex(1001);

// extract snap-able points from the basemap, and display them as points on the map if initial render within zoom
if (this.zoom < snapsZoom) {
pointsSource.clear();
const extent = map.getView().calculateExtent(map.getSize());
getSnapPointsFromVectorTiles(osVectorTileBaseMap, extent);
}

// continue to fetch & update snaps as map moves
map.on("moveend", () => {
const currentZoom: number | undefined = map.getView().getZoom();
if (currentZoom && currentZoom < 20) {
if (currentZoom && currentZoom < snapsZoom) {
pointsSource.clear();
return;
}

// extract snap-able points from the basemap, and display them as points on the map
// timeout minimizes snap updates mid-pan/drag
setTimeout(() => {
pointsSource.clear();
const extent = map.getView().calculateExtent(map.getSize());
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