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WebGL Scatter (svg axes, quadtree hover)

  • +page.svelte
  • ./_components/Scatter.webgl.svelte
  • ./_components/AxisX.svelte
  • ./_components/AxisY.svelte
  • ./_components/QuadTree.html.svelte
  • ./_data/points.csv
<script>
  import { LayerCake, Svg, WebGL, Html } from 'layercake';

  import ScatterWebGL from './_components/Scatter.webgl.svelte';
  import AxisX from './_components/AxisX.svelte';
  import AxisY from './_components/AxisY.svelte';
  import QuadTree from './_components/QuadTree.html.svelte';

  // This example loads csv data as json using @rollup/plugin-dsv
  import data from './_data/points.csv';

  const xKey = 'myX';
  const yKey = 'myY';

  const r = 3;
  const xyPadding = 6;

  data.forEach(d => {
    d[yKey] = +d[yKey];
  });
</script>

<div class="chart-container">
  <LayerCake
    padding={{ top: 5, right: 5, bottom: 20, left: 25 }}
    x={xKey}
    y={yKey}
    xPadding={[xyPadding, xyPadding]}
    yPadding={[xyPadding, xyPadding]}
    {data}
  >
    <Svg>
      <AxisX />
      <AxisY tickMarks={false} ticks={5} />
    </Svg>

    <WebGL>
      <ScatterWebGL {r} />
    </WebGL>

    <Html>
      <QuadTree>
        {#snippet children({ x, y, visible })}
          <div
            class="circle"
            style="top:{y}px;left:{x}px;display: {visible ? 'block' : 'none'};"
          ></div>
        {/snippet}
      </QuadTree>
    </Html>
  </LayerCake>
</div>

<style>
  /*
    The wrapper div needs to have an explicit width and height in CSS.
    It can also be a flexbox child or CSS grid element.
    The point being it needs dimensions since the <LayerCake> element will
    expand to fill it.
  */
  .chart-container {
    width: 100%;
    height: 250px;
  }
  .circle {
    position: absolute;
    border-radius: 50%;
    background-color: rgba(171, 0, 214);
    transform: translate(-50%, -50%);
    pointer-events: none;
    width: 10px;
    height: 10px;
  }
</style>