The COSMIC Desktop GUI

improv-cosmic is a second desktop front end, built on libcosmic, the toolkit the COSMIC desktop (System76, Pop!_OS) is made of. It is a native COSMIC application: it takes the desktop's theme, light or dark, and its accent color, and it opens, saves and prints through the XDG desktop portals. It works on the same models as improv-gui, the NeXTSTEP-style workspace, and both stay: pick the one that fits your desktop.

The demo model's Price measure in COSMIC's dark theme: the header bar, the Rows, Columns and Pages strips of category tiles, the grid (the cursor in the accent color), and the formula list.

It is a preview. It covers the everyday work on a model (see What it does), not yet all of improv-gui; see Not yet.

Running it

improv-cosmic is its own Cargo workspace, crates/gui_cosmic (libcosmic pins its own toolkit stack, apart from the egui GUI's). From a checkout:

cd crates/gui_cosmic
cargo run --locked --release -- ../../sample.db
cargo run --locked --release -- 'postgres://me@127.0.0.1/sales?model=plan'

On Linux the build needs libxkbcommon-dev and libwayland-dev (Debian names). It runs on Wayland (COSMIC's own compositor, or any other) and on X11. ICED_BACKEND=tiny-skia selects the software renderer, for a machine with no GPU backend. Without an argument the model is in memory only.

What it does

• The grid. The shown measure (pick it in the header bar's list) as a grid that draws only the cells in view, so a measure of a million cells scrolls as fast as a small one. Arrows, Tab, Page Up and Down, Home and End move; Ctrl+Home and Ctrl+End go to the first and last cell; Shift extends a range.
• Editing. Type on a cell, or press Enter or F2, or double-click it, to edit it; Enter commits and moves down, Escape cancels, Delete clears. The text is read by the measure's value type, as everywhere in Improv: 42 in a Text measure is text, and text that is not a number in a Number measure is refused with the reason. Derived cells are computed, not entered.
• Formulas. Under the grid, every formula in Improv's numbered list, 1. Revenue = Price * Quantity. Click one to edit it. A formula that does not parse stays open with the error located: the text with carets under the wrong part, the message, and a hint (did you mean Quantity?). While a name is typed, the names and functions that complete it appear; Tab or Enter takes the first.
• Pivoting. Above the grid, the measure's categories as tiles in three strips: Rows, Columns and Pages. Drag a tile to another strip to pivot; several on one strip stack. A page tile has a list of its items. Swap exchanges rows and columns. No formula changes, only the layout.
• Views. Save view stores the layout under a name; the Views list opens one. Views are the model's, shared with improv-gui, the TUI and improv save-view.
• Charts. Chart shows the measure as grouped bars in its current layout, in the theme's accent and palette colors.

• Copy and paste. Ctrl+C copies the range as tab-separated values and, where the clipboard takes several formats (Wayland), as an HTML table with its headers too, so spreadsheets and editors paste it as a table. Ctrl+V pastes a range from either at the cursor, as one change.
• Open, Save As and Print. Through the desktop's file chooser and print dialog (the XDG portals); on Windows, the native file dialogs, and Print opens the PDF in the default viewer. A model file dropped on the window opens. Every change is saved as it is made, as in the other front ends.
• Undo. Ctrl+Z undoes a cell edit, a paste, a formula or a saved view; Ctrl+Shift+Z or Ctrl+Y redoes.

The model loads, recalculates and saves on a thread of its own: the window keeps drawing while a large model opens or a formula rebuilds the engine.

Platforms

Not yet

What improv-gui has and improv-cosmic does not, yet: several matrices on one canvas, filters, the CSV import wizard, number formats, scenarios, named LAMBDAs, adding and deleting categories, items and measures, the function browser, and live refresh of a Postgres model another writer changes. The grid is drawn on a canvas, so a screen reader sees the header bar and the formula list but not the cells yet.

See also

improv-cosmic(1), and the design note docs/reviews/2026-11-02-cosmic-gui.md (the stack, the pins, the platform matrix and the plan).