Menu

Brush

1980
1990
2000
2010
0
2
4
6
  • +page.svelte
  • ./_components/Line.svelte
  • ./_components/Area.svelte
  • ./_components/AxisX.percent-range.html.svelte
  • ./_components/AxisY.percent-range.html.svelte
  • ./_components/Brush.html.svelte
  • ./_data/points.csv
<script>
  import { LayerCake, ScaledSvg, Html } from 'layercake';

  import Line from './_components/Line.svelte';
  import Area from './_components/Area.svelte';
  import AxisX from './_components/AxisX.percent-range.html.svelte';
  import AxisY from './_components/AxisY.percent-range.html.svelte';
  import Brush from './_components/Brush.html.svelte';

  // This example loads csv data as json and converts numeric columns to numbers using @rollup/plugin-dsv. See vite.config.js for details
  import data from './_data/points.csv';

  let brushExtents = $state([null, null]);

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

  let brushedData = $derived.by(() => {
    const slicedData = data.slice(
      (brushExtents[0] || 0) * data.length,
      (brushExtents[1] || 1) * data.length
    );
    if (slicedData.length < 2 && brushExtents[0] !== null) {
      return data.slice(brushExtents[0] * data.length, brushExtents[0] * data.length + 2);
    }
    return slicedData;
  });
</script>

<div class="brushed-chart-container">
  <LayerCake
    ssr
    percentRange
    padding={{ bottom: 20, left: 25 }}
    x={xKey}
    y={yKey}
    yDomain={[0, null]}
    data={brushedData}
  >
    <Html>
      <AxisX
        ticks={ticks => {
          const filtered = ticks.filter(t => t % 1 === 0);
          if (filtered.length > 7) {
            return filtered.filter((t, i) => i % 2 === 0);
          }
          return filtered;
        }}
      />
      <AxisY ticks={4} />
    </Html>
    <ScaledSvg>
      <Line stroke="#00e047" />
      <Area fill="#00e04710" />
    </ScaledSvg>
  </LayerCake>
</div>

<div class="brush-container">
  <LayerCake ssr percentRange padding={{ top: 5 }} x={xKey} y={yKey} yDomain={[0, null]} {data}>
    <ScaledSvg>
      <Line stroke="#00e047" />
      <Area fill="#00e04710" />
    </ScaledSvg>
    <Html>
      <Brush bind:min={brushExtents[0]} bind:max={brushExtents[1]} />
    </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.
  */
  .brushed-chart-container {
    width: 100%;
    height: 80%;
  }
  .brush-container {
    width: 100%;
    height: 20%;
  }
</style>