Model: Series.trendlines (Vec<Trendline>, serde default) with kind
(linear, exponential, logarithmic, polynomial 2..6, power, moving
average 2..255), name, forward/backward forecast, set intercept,
equation / R² display and line colour, width and dash.
XLSX: read and write <c:trendline> in CT_Trendline child order, placed
after dLbls and before the data references in line, bar, area, scatter,
bubble and stock series; unknown types are skipped.
Chart: least-squares fits (transformed for exp/log/power, skipping
non-positive values; polynomials via normal equations on centred,
scaled x with partial pivoting), moving averages, forecasts that widen
the category or x axis, clipping to the plot, equation and R² labels and
legend entries ("Linear (Sales)"). Degenerate data draws nothing.
Engine: chart.addElement element="trendline" adds (type, series, order,
period, forward, backward, displayEquation, displayRSquared) or removes
trendlines; document.inspect lists each chart's trendlines.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
cell_param returned None for any cell argument it could not parse, so every
command that falls back to the selection (cell.set, view.freezePanes,
formulas.trace*, insert.* and others) silently used the active cell instead:
set_cell with cell "ZZZZ0" wrote A1 and reported success. It also dropped a
sheet prefix, so "Other!B2" was applied to the active sheet.
cell_param now returns Result<Option<CellRef>>. An absent or null value is still
None, so the selection fallback is unchanged; an unparsable or non-string value
is an error; a sheet prefix naming a sheet other than the one the command works
on is an error.
cell_param_on is for the commands that resolve their own sheet (cell.get, links,
comments, notes, checkboxes, chart placement, paste): they accept a prefix naming
that sheet. cell.set resolves its own target sheet and still writes to another
existing sheet.
- ui-egui: title bar with QAT, full ribbon (Home/Insert/Draw/Page Layout/Formulas/Data/
Review/View/Automate + Table/Chart Design), formula bar with Name Box, virtualised grid
(frozen panes, overflow, borders, CF data bars/scales/icons, tables, sparklines, filter
buttons, charts/pictures/shapes), in-cell editor with point mode, reference colouring,
autocomplete and argument hints, sheet tabs, status bar, dialogs, control channel
- apps/sheetcraft: desktop app (control server, file dialogs, prefs, drag & drop)
- chart: toolkit-free chart layout/rendering for 25 chart kinds + sparklines + rasteriser
- mcp + sheetcraft-cli: MCP server (headless or bridged) and CLI (info/convert/eval/cat/run/mcp)
- xtask (ci/layers/assets/wasm/version/parity), release workflows, packaging, placeholder icon
- automatic row heights
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Pranav Chandra