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Column annotated

1979
1980
1981
1982
1983
0
5
10
15
Example text...

Since we want an ordinal x-axis and Layer Cake defaults to a linear scale, pass in a custom scale to xScale with a few formatting options. Set the y-scale to always start at 0 so you don't show misleading differences between groups.

Since it's tricky to server-side render circles in SVG, this example uses a second <LayerCake> component for the arrow, which renders client-side and uses the position='absolute' prop to make sure the two cakes are super-imposed on one another.

For the annotation arrowhead, note that you may need to provide an explicit link to your SVG marker id, such as in ./_components/Arrows.svelte using window.location.href.

  • +page.svelte
  • ./_components/Column.svelte
  • ./_components/AxisX.percent-range.html.svelte
  • ./_components/AxisY.percent-range.html.svelte
  • ./_components/AnnotationsData.html.svelte
  • ./_components/Arrows.svelte
  • ./_components/ArrowheadMarker.svelte
  • ./_modules/arrowUtils.js
  • ./_data/groups.csv
<script>
  import { LayerCake, Svg, ScaledSvg, Html } from 'layercake';
  import { scaleBand } from 'd3-scale';

  import Column from './_components/Column.svelte';
  import AxisX from './_components/AxisX.percent-range.html.svelte';
  import AxisY from './_components/AxisY.percent-range.html.svelte';
  import Annotations from './_components/AnnotationsData.html.svelte';
  import Arrows from './_components/Arrows.svelte';
  import ArrowheadMarker from './_components/ArrowheadMarker.svelte';

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

  const xKey = 'year';
  const yKey = 'value';

  const annotations = [
    {
      text: 'Example text...',
      [xKey]: '1980',
      [yKey]: 14,
      dx: 15, // Optional pixel values
      dy: -5,
      arrows: [
        {
          clockwise: false, // true or false, defaults to true
          source: {
            anchor: 'left-bottom', // can be `{left, middle, right},{top-middle-bottom}`
            dx: -2,
            dy: -7
          },
          target: {
            // These can be expressed in our data units if passed under the data keys
            [xKey]: '1980',
            [yKey]: 4.5,
            // Optional adjustments
            dx: 2,
            dy: 5
          }
        },
        {
          source: {
            anchor: 'right-bottom',
            dy: -7,
            dx: 5
          },
          target: {
            // Or if they are percentage strings they can be passed directly
            x: '68%',
            y: '48%'
          }
        }
      ]
    }
  ];

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

<div class="chart-container">
  <LayerCake
    ssr
    percentRange
    position="absolute"
    padding={{ top: 0, right: 0, bottom: 20, left: 20 }}
    x={xKey}
    y={yKey}
    xScale={scaleBand().paddingInner(0.028).round(true)}
    xDomain={['1979', '1980', '1981', '1982', '1983']}
    yDomain={[0, null]}
    {data}
  >
    <ScaledSvg>
      <Column />
    </ScaledSvg>

    <Html>
      <AxisX gridlines={false} />
      <AxisY gridlines={false} snapBaselineLabel />
      <Annotations {annotations} />
    </Html>
  </LayerCake>

  <!--
    Add a second cake for the arrows that is rendered once the page is loaded
    since the arrows are hard to draw within the viewbox
  -->
  <LayerCake
    position="absolute"
    padding={{ top: 0, right: 0, bottom: 20, left: 20 }}
    x={xKey}
    y={yKey}
    xScale={scaleBand().paddingInner(0.028).round(true)}
    xDomain={['1979', '1980', '1981', '1982', '1983']}
    yDomain={[0, null]}
    {data}
  >
    <Svg>
      {#snippet defs()}
        <ArrowheadMarker />
      {/snippet}
      <Arrows {annotations} />
    </Svg>
  </LayerCake>
</div>

<style>
  .chart-container {
    width: 100%;
    height: 400px;
    position: relative;
  }
</style>