Chart Export

Graphic Walker provides programmatic chart export through the IGWHandler ref. Export individual charts or iterate through all charts in a workbook.

Setup

Access the export API through a React ref:

import { useRef } from 'react';
import { GraphicWalker } from '@kanaries/graphic-walker';
import type { IGWHandler } from '@kanaries/graphic-walker';
 
function App() {
  const gwRef = useRef<IGWHandler>(null);
 
  return (
    <GraphicWalker
      ref={gwRef}
      data={data}
      fields={fields}
    />
  );
}

Export Current Chart

Use exportChart() to export the currently visible chart:

async function handleExport() {
  if (!gwRef.current) return;
 
  // Export as SVG (default)
  const svgResult = await gwRef.current.exportChart('svg');
 
  // Export as data URL (base64 PNG)
  const pngResult = await gwRef.current.exportChart('data-url');
}

Export Result Structure

The IChartExportResult contains:

Property	Type	Description
`mode`	`'svg' \| 'data-url'`	Export format
`title`	`string`	Chart name
`nCols`	`number`	Number of facet columns
`nRows`	`number`	Number of facet rows
`charts`	`Array`	Array of chart panels
`charts[].data`	`string`	SVG markup or data URL string
`charts[].width`	`number`	Chart width
`charts[].height`	`number`	Chart height
`charts[].canvas()`	`Function`	Returns the canvas/SVG DOM element
`container()`	`Function`	Returns the chart container element
`chartType`	`string`	The geometry type

Export All Charts

Use exportChartList() to iterate through all charts in the workbook. It returns an AsyncGenerator:

async function exportAll() {
  if (!gwRef.current) return;
 
  for await (const item of gwRef.current.exportChartList('svg')) {
    console.log(`Exporting chart ${item.index + 1} of ${item.total}`);
    console.log('Title:', item.data.title);
    console.log('SVG:', item.data.charts[0]?.data);
 
    // item.hasNext tells you if more charts follow
  }
}

Download as SVG File

async function downloadSVG() {
  if (!gwRef.current) return;
 
  const result = await gwRef.current.exportChart('svg');
  const svgData = result.charts[0]?.data;
  if (!svgData) return;
 
  const blob = new Blob([svgData], { type: 'image/svg+xml' });
  const url = URL.createObjectURL(blob);
 
  const link = document.createElement('a');
  link.href = url;
  link.download = `${result.title || 'chart'}.svg`;
  link.click();
 
  URL.revokeObjectURL(url);
}

Download as PNG File

async function downloadPNG() {
  if (!gwRef.current) return;
 
  const result = await gwRef.current.exportChart('data-url');
  const dataUrl = result.charts[0]?.data;
  if (!dataUrl) return;
 
  const link = document.createElement('a');
  link.href = dataUrl;
  link.download = `${result.title || 'chart'}.png`;
  link.click();
}

Checking Render Status

Before exporting, you can check if the chart is ready:

async function safeExport() {
  if (!gwRef.current) return;
 
  // Wait for idle status
  if (gwRef.current.renderStatus !== 'idle') {
    await new Promise<void>(resolve => {
      const dispose = gwRef.current!.onRenderStatusChange(status => {
        if (status === 'idle') {
          dispose();
          resolve();
        }
      });
    });
  }
 
  return gwRef.current.exportChart('svg');
}

Navigating Charts Before Export

Switch to a specific chart tab before exporting:

// Export the third chart
gwRef.current.openChart(2);  // 0-indexed
 
// Wait for render, then export
const result = await safeExport();