rust-office-charts

Render native Office Open XML chart parts to SVG in Rust. The crate also reads cached chart values into a serializable model that preserves series order, sparse point indices and category hierarchy.

use extend_office_charts::{render_chart, RenderOptions};

fn render_slide_chart(xml: &str, width: f64, height: f64) -> Option<String> {
    let chart = render_chart(xml, &RenderOptions {
        width: Some(width),
        height: Some(height),
        ..Default::default()
    })?;
    Some(chart.svg)
}

The host opens the Office package and supplies the chart XML, size in CSS pixels, resolved theme colors, font and related chart style parts. The default uses the chart's cached values. A spreadsheet can supply current workbook values through RenderOptions::data in source series order, and set spreadsheet_defaults for omitted spreadsheet properties. Unsupported layouts return None so the host can use its own fallback.

Chart artwork reuses rust-office-art. Embedded picture fills support tiling at each element's dimensions and supported image adjustments; picture markers retain series and point selection. Supported effect lists add inner shadows, reflections, soft edges and blur while retaining existing chart shadows, gradients and bevel rendering. Supported effect trees reuse the shared bounded graph renderer. Raster inputs are embedded data URLs; BMP and TIFF are normalized for browser display.

For chart-attached artwork, supply RenderOptions::drawings (drawings in the browser API), keyed by each chart userShapes relationship ID. Each ChartDrawing contains the saved drawing XML and its own relationship-ID-to-image map. Relative and absolute anchors compose preset/custom shapes, connectors, pictures and nested groups, including supported pattern fills, gradients and closed compound outlines. Text supports runs, basic wrapping, alignment and rotation; this is not full native text-layout or WordArt parity. Missing or unsupported artwork is reported with SVG descriptions. The host retains original parts for export and resolves only authorized embedded resources. General effect graphs, 3D artwork and full SmartArt layout generation remain outside this integration.

Supported font stacks include Carlito for Calibri, Arimo for Arial, Tinos for Times New Roman and Cousine for Courier New. Aptos and Aptos Narrow use host-provided fonts or generic sans-serif fallbacks, with estimated text widths. The shared @extend-ai/office-fonts package in this repository supplies browser loading, portable SVG embedding and native font assets. The host must load fonts before measuring or displaying text; generating an SVG does not install fonts. Selected Cartesian title, axis and legend layouts and ChartEx text use advance widths from the same four bundled font families, with existing estimates retained for other families or missing glyphs. These advances do not perform kerning, ligature substitution or complex-script shaping, and other chart layout paths still use estimates. Each metric table retains its font license alongside it.

Set interactive to emit hit targets across the classic and supported ChartEx families. Targets carry a data-chart-kind and a zero-based source series ordinal in data-chart-series. Point targets carry the source cache index in data-chart-point. Markers and point anchors can also carry data-chart-x and data-chart-y in SVG user coordinates. Legend entries use legendEntry. Hosts handle pointer events and selection state by finding the closest target ancestor.

Aggregate geometry, including histogram bins, box summaries, merged hierarchy branches and the combined split-pie slice, selects its source series. A surface facet selects the nearest projected source vertex. Surface color-band legends represent value ranges spanning series and have no source-series target. Interactive mode preserves visible rendering, and the default output omits these targets.

Default builds include the classic chart families, 3D and surface plots, and supported ChartEx types. Consumers that use only two-dimensional bar, line, area and scatter charts can disable default features to omit the additional renderers and map cache decoder.

Maps use the saved Office boundary cache, including its hierarchy, projection and attribution. The optional map-fallback feature adds offline country and US-state boundaries for spreadsheet charts without a usable cache. This fallback does not run for DOCX. An uncached location outside the atlas renders the chart frame and legend with an SVG description explaining that boundaries are unavailable. The browser /full entry includes this feature; the compact entry does not load its data.

Extracted from extend-hq/react-docx. Licensed under the MIT License.