MapPoints.html.svelte component

<!--
  @component
  Generates canvas dots onto a map using [d3-geo](https://github.com/d3/d3-geo).
 -->
<script>
  import { getContext } from 'svelte';

  const { data, width, height } = getContext('LayerCake');

  /** @type {Function} projection - A D3 projection function. Pass this in as an uncalled function, e.g. `projection={geoAlbersUsa}`. */
  export let projection;

  /** @type {Number} [r=3.5] - The point's radius. */
  export let r = 3.5;

  /** @type {String} [fill='yellow'] - The point's fill color. */
  export let fill = 'yellow';

  /** @type {String} [stroke='#000'] - The point's stroke color. */
  export let stroke = '#000';

  /** @type {Number} [strokeWidth=1] - The point's stroke width, in pixels. */
  export let strokeWidth = 1;

  /** @type {Number} [opacity=1] - The point's opacity. */
  export let opacity = 1;

  /** @type {Array} [features] - A list of GeoJSON features to plot. If unset, the plotted features will defaults to those in `$data.features`, assuming this field a list of GeoJSON features. */
  export let features = undefined;

  $: projectionFn = projection()
    .fitSize([$width, $height], $data);
</script>

<div class="points">
<!-- To scale the circle by size, set width and height to `$rGet(d.properties)` -->
{#each (features || $data.features) as d}
  <div
    class="point"
    style="
      top: {projectionFn(d.geometry.coordinates)[1]}px;
      left: {projectionFn(d.geometry.coordinates)[0]}px;
      width: {r * 2}px;
      height: {r * 2}px;
      border-width: {strokeWidth}px;
      border-color: {stroke};
      background-color: {fill};
      opacity: {opacity};
    "
  >
  </div>
{/each}
</div>

<style>
  .point {
    position: absolute;
    border-radius: 50%;
    border-style: solid;
  }
</style>