gridcraft/docs/chart-parity.md

Chart parity

Last reviewed: 2026-10-18 · Last updated: 2026-10-18 · Change: trivial (stale chart notes: stock/combo, treemap/sunburst, box and waterfall kinds survive XLSX round-trip; PRs #158 and #161 merged) · Target: Microsoft Excel (Microsoft 365), Excel for Mac 16.113.4

Excel's chart types and chart elements against GridCraft. Part of target-app-parity.md. Breadth ~50%, ready ~30%, 40–60 h (estimated).

Sources: crates/model/src/features.rs (ChartKind, Chart, Series), crates/chart/src (layout and rendering), crates/xlsx/src/chart.rs (DrawingML chart parts), merged PRs #62, #116, #158 and #161, and issue #190.

Chart types

Excel type	Excel subtypes	GridCraft	Notes
Column	clustered, stacked, 100% stacked, 3-D clustered/stacked/100%, 3-D column	3 of 7	no 3-D
Bar	clustered, stacked, 100%, 3-D ×3	3 of 6	no 3-D
Line	line, stacked, 100% stacked, with markers ×3, 3-D line	3 of 7 (line, with markers, stacked)	no 100% stacked; smoothed lines landed (#62)
Pie	pie, 3-D pie, pie of pie, bar of pie, doughnut	2 of 5 (pie, doughnut)	no exploded, pie of pie, bar of pie
Area	area, stacked, 100%, 3-D ×3	2 of 6	no 100%, no 3-D
X Y (scatter)	markers, smooth lines (±markers), straight lines (±markers)	2 of 5	no smooth lines
Bubble	bubble, 3-D bubble	1 of 2
Stock	high-low-close, open-high-low-close, volume-HLC, volume-OHLC	1 kind
Surface	3-D surface, wireframe, contour, wireframe contour	0 of 4
Radar	radar, with markers, filled	1 of 3
Treemap, Sunburst	1 each	2 of 2
Histogram, Pareto	2	1 of 2	no Pareto
Box & Whisker	1	1 of 1	exclusive (default) and inclusive quartiles per series; XLSX round-trip; chart.set {quartiles} changes all series
Waterfall, Funnel	2	2 of 2	lose their kind in XLSX (PR #161)
Box & Whisker	1	1 of 1
Waterfall, Funnel	2	2 of 2
Filled map	1	0	needs geographic boundary data (licensing decision)
Combo	custom combinations, secondary axis	yes (line on secondary axis)
Total	~60 subtypes	25 (~42%)	usage-weighted breadth higher (~65%): column, bar, line, pie and scatter dominate

Chart elements and formatting

Element	Excel	GridCraft
Move and resize the chart object	yes	yes (corner handle, Format Chart Area Size fields)
Chart title, axis titles	text, linked to cells, full formatting	text only
Legend	position, overlay, formatting, per-entry delete	position only
Data labels	value, category, series, percentage, from cells, callouts, position	one on/off flag
Gridlines	major/minor per axis, formatting	one on/off flag
Axis options	min/max/units, log scale, reverse order, crossing point, display units, date axis, number format	missing (auto only)
Multi-level category axis (a category range two or more columns wide beside the values: year beside month)	the outer levels grouped under the labels with separators	read (multiLvlStrRef), drawn (rows under the labels; columns beside them in bar charts; up to three outer levels), written back with Excel's level caches
Secondary axis	any series	line series in combo charts
Trendlines	linear, exponential, logarithmic, polynomial, power, moving average, equation and R²	all six types, several per series, name, forward/backward forecast, set intercept, equation and R² label, line colour/width/dash; read, written and drawn on 2-D column, bar, line, area, scatter and bubble series; chart.addElement trendline adds/removes them. No Format Trendline pane, label position/number format not kept
Error bars	fixed, %, standard deviation/error, custom	missing
Up/down bars, high-low lines, drop lines, series lines	yes	missing
Data table under the chart	yes	missing
Per-series / per-point fill, line, marker, effects	Format pane for every element	series colour only; Format Chart pane covers chart-level options
Chart styles and colour palettes	~16 styles × colour sets	style number stored, own palettes
Chart sheets	yes	kept, not editable: not shown, and written back unchanged in their place on save (#727); left out when a sheet they plot is deleted or renamed. No F11 / Move Chart > New sheet
Chart templates (.crtx)	yes	missing
Recommended Charts	yes	dialog with recommendations from the data's shape (own heuristic) and an All Charts list, live previews (#215)
Switch Row/Column, Select Data	yes	yes (Switch on charts read from files landed in #116)
Recommended Charts	yes	partial (Insert ▸ Recommended)
Switch Row/Column, Select Data	yes	yes (Switch on charts read from files landed in #116); Select Data dialog: data range, remove series, Horizontal (Category) Axis Labels (#287). No series add/edit or hidden/empty cell options
Sparklines (line, column, win/loss, markers, axis)	yes	line, column, win/loss
PivotCharts	yes	Insert ▸ PivotChart (insert.pivotChart): bound to a PivotTable's report, rebuilt on refresh and layout changes, c:pivotSource round trip; no field buttons, innermost category level only
Animation on data change	yes (Windows)	no

XLSX round-trip

Charts are read from and written to DrawingML chart parts, but only the fields the model holds survive: anything else (axis scaling, label options, error bars, per-point formats, chartex extensions) is lost when GridCraft saves a workbook it opened. That is the main reason charts are ~30% ready: a user who opens an Excel workbook with charts and saves it gets simpler charts back.

Series data, categories and names may refer to defined names, as dynamic (OFFSET) ranges do: Excel writes a workbook-scoped name as [0]!Name in <c:f>. GridCraft reads it as the bare name and writes it back with [0]!; a sheet-scoped name is written Sheet!Name. Excel needs the qualifier: with a bare name in <c:f> it draws the whole chart blank, without a repair prompt (observed in Excel for Windows, Microsoft 365). External books ([1]Sheet1!…) are kept as they are (#1686). Such series get no numCache/strCache on save (#1690).

Work (40–60 h)

1. Chart resizing (#190): 1–2 h.
2. Preserve unmodelled chart XML on round-trip (keep the original part, patch only edited fields): 6–10 h.
3. Axis options, label options, gridlines per axis, legend formatting: 10–15 h.
4. Error bars; Format Trendline pane (trendlines landed): 4–6 h.
5. Per-element Format pane parity, smoothed lines, exploded pie, pie/bar of pie, 100% variants: 8–12 h.
6. 3-D column/bar/pie/area, surface and contour, Pareto: 8–12 h.
7. Chart sheets, templates and PivotChart field buttons: 5–8 h. Filled map: owner decision on boundary data.

Revision history

Date	Change	Summary
2026-10-18	trivial	Stale notes: stock/combo, treemap/sunburst, box and waterfall kinds survive XLSX round-trip (PRs #158, #161)
2026-10-16	trivial	Series that refer to defined names ([0]!Name, Sheet!Name) resolve instead of showing #NAME?, and are saved qualified, as Excel needs (#1686)
2026-10-16	minor	Box & whisker quartiles default to exclusive, honor each series on draw and XLSX round-trip; chart.set {quartiles} changes the method (#1453)
2026-10-13	minor	Multi-level category axes: read, drawn (outer levels under or beside the labels), written back with level caches
2026-10-12	trivial	chart sheets are kept on save, still not editable (#727)
2026-10-11	minor	Trendlines: all six types modelled, round-tripped through c:trendline, drawn with forecast and equation/R² labels; chart.addElement trendline
2026-10-11	minor	PivotCharts (insert.pivotChart)
2026-10-11	minor	Recommended Charts dialog with previews (#215)
2026-10-11	minor	Select Data dialog with category axis labels; a blank top-left cell makes the first column the categories (#287)
2026-10-10	minor	Smooth lines (#62) and Switch Row/Column on file charts (#116) landed; chart resize bug (#190)
2026-10-10	major	Created from a source audit: 25 kinds (25 of ~60 subtypes), element gaps, round-trip loss