# Math, diagrams, code and calculations

LaTeX formulas, Mermaid diagrams and code blocks with highlighting, calculating right in the text and figures from databases.

## Formulas, diagrams and code

- **Formulas** in LaTeX: as a block with `/math`, inside the text with `/inlinemath`. The preview appears while you type. Building blocks such as fraction, root, superscript, subscript, vector, cross product, ±, π and sum sit above the input.
- **Mermaid diagrams**: a click or <kbd>Enter</kbd> opens the source and preview. Up to 20,000 characters and 500 edges. In dark mode Mermaid diagrams are drawn dark, and redrawn when you switch; downloads (SVG/PNG) and printouts stay light.
- **draw.io diagrams** (`/drawio`): open the draw.io editor in a large window; **Save** applies the diagram as one step you can undo. A double-click, <kbd>Enter</kbd> or the pencil on the block opens it again. Flowplan stores the drawing and a picture of it: when viewing – on shared pages, in presentations and offline too – it doesn't load draw.io at all and only shows the picture (cleaned, without scripts and without content from elsewhere). Drawing and picture may each be up to 800 kB.
  - **Maximize:** the arrows button at the top right of the window (next to the close button) enlarges draw.io to the whole browser window; the same button (**Restore size**) brings the window back. It works from the keyboard too. The diagram stays open and unsaved changes are not lost; <kbd>Esc</kbd> and **Close** ask before discarding changes as before. The device remembers the choice: the next diagram opens the way you left the last one. On a phone draw.io fills the screen anyway (keeping clear of the notch and the home indicator), so there is no button there.
  - **A page for one diagram:** the **Diagram page** template (under [Templates](/templates#starter-templates), category *Knowledge & documentation*) creates a full-width page with one empty draw.io diagram and opens draw.io right away. On a full-width page the saved picture uses the whole width, and an empty diagram is a large area rather than a thin strip. There is no separate page type for this as there is for whiteboards – the diagram page is a document, so you can add text, more diagrams or other blocks.
  - **Where draw.io runs:** by default Flowplan uses `embed.diagrams.net`. While you draw, the diagram's content goes to that service; the window says so. With `DRAWIO_URL` the instance points to its own draw.io (for example the `jgraph/drawio` container), and everything stays with you (see [Configuration](/configuration-storage#legal-and-interface)).
  - **Look:** under **Settings → Appearance → Editor**: **draw.io theme** *Automatic* (follows Flowplan), *Light* or *Dark*, and **draw.io interface** *Default*, *Minimal* or *Sketch*. The choice applies to this device.
  - **Export:** in the ZIP export every diagram becomes a `.drawio.svg` file that draw.io can open again; in a single Markdown file and in the Git export it is a ` ```drawio ` block with the drawing, which the import turns back into a diagram (the picture is made the next time it is saved). PDF and EPUB show the picture.
- **Code blocks**: the language is shown in the block's header with its full name ("JavaScript", "C++", "Angular TypeScript", "Plain text"). A click opens a list with a search – it finds names, aliases and file extensions (`ts`, `py`, `yml`, `tf`, `.rs` …). The languages you chose last come first (remembered in this browser). There are more than 240 languages with the same grammars as in VS Code – among them Svelte, Vue, Astro, JSX/TSX, Terraform, TOML, Typst, Zig, Prisma, GDScript, Nushell, systemd units, SSH config, Git commit messages, log files, CSV/TSV and .env files. **Line wrap** and **Copy** are at hand. <kbd>Tab</kbd> indents by two spaces.
- **Language detection**: when you paste code into a block without a language (plain text), Flowplan suggests a language if it is clearly recognisable – "Looks like Python – set?". One click sets it, the × dismisses the suggestion. Flowplan never changes the language by itself.
- **Preview**: code blocks in HTML, SVG (language XML with `<svg>`), Markdown, Mermaid, LaTeX and Typst show the switch **Code / Preview / Split** in their header. *Split* puts code and preview side by side, on a phone one below the other. The view is stored in the block; people who only read a page (read access, published pages, presentations) see the preview unless the block says otherwise, and can switch for themselves without changing anything. Errors (such as a typo in the diagram or in Typst, with the line number) show in place of the preview.
  - **HTML** runs in a sealed frame: no scripts, no forms, no access to Flowplan or the network. Pictures from the web stay blank; embedded pictures (`data:`) and styles work. The height follows the content.
  - **SVG**, **Mermaid** and **Typst** show as a picture – without scripts or links.
  - **Markdown** is converted as on import, **LaTeX** shows formulas with KaTeX (separated by blank lines, with or without `$$ … $$`; not whole LaTeX documents with `\documentclass`).
  - **Typst** loads the first time it is used (a few MB, from your own server, not from the web); Typst packages (`@preview/…`) and files are not available.
  - New Mermaid code blocks (` ```mermaid ` or the language *Mermaid* chosen) show the diagram right away, empty ones code and diagram side by side. The separate Mermaid block (`/mermaid`) stays.
- **Line numbers**: the **…** menu in a code block's header turns **Line numbers** on or off for that block, sets the **First line number** (say 10 for an excerpt) and **highlights lines** – e.g. `3-5, 8`, counted as shown. The numbers cannot be selected and are not copied; with line wrap they stand at the first row of a wrapped line. Blocks without a setting of their own follow **Settings → Appearance & language → Editor → Show line numbers by default** (on this device).
- **Collapse**: code blocks with more than 25 lines appear collapsed – 10 lines high, scrolling inside, faded at the bottom. **Show all N lines** expands them, **Collapse** folds them again (both reachable by keyboard). People who may edit store the state in the block; readers only expand for themselves. The **…** menu sets **Collapsed** and the **Collapsed height** (5, 10, 15, 20 or 30 lines). Printing and every export always show the whole code.
- A language's highlighting loads with the first code block of that language; until then the code shows briefly without colours. Very long code blocks (more than 50,000 characters) stay without highlighting.
- **Fractions**: `/Fraction` (or `/Bruch`) inserts a formula inside the sentence.

![A Markdown code block in the split view: the code with line numbers and a highlighted line on the left, the rendered release notes on the right](/screenshots/code-preview.webp "A code block in Markdown, with line numbers, a highlighted line and the preview beside it.")

## Calculating in text

Flowplan only calculates when you want it to – exactly, with fractions, in German or English notation (`2,5` or `2.5`, `×`, `²`, `√`, `€`):

- **Hint after "="**: type a calculation followed by `=`, such as `12 × 2,400 € =` or `3/4 + 1/6 =`, and the result appears greyed out behind it. <kbd>Tab</kbd> accepts it, <kbd>Esc</kbd> or typing on dismisses it.
- **Selected text**: select a calculation, a term or an equation; the text menu (also on right-click) shows what is possible under **Calculate** and inserts the result after it with one click:
  - **Result** and **Reduce** as an exact fraction, plus **As a decimal** – `12/18 = 2/3`
  - **Expand**, including the binomial formulas – `(a + b)² = a² + 2ab + b²`
  - **Factor** – `x² − 9 = (x − 3)(x + 3)`, `4x² − 12x + 9 = (2x − 3)²`, `6x² + 9x = 3x(2x + 3)`, also with several variables: `a³ − b³ = (a − b)(a² + ab + b²)`, `x² + 2xy + y² − 1 = (x + y − 1)(x + y + 1)`, by grouping `ax + ay + bx + by = (x + y)(a + b)`; **Factor with roots** splits further into real factors: `x² − 2 = (x − √2)(x + √2)`
  - **Simplify** algebraic fractions – `(x² − 1)/(x − 1) = x + 1`, `1/x + 1/(x + 1) = (2x + 1)/(x(x + 1))`
  - **Solve for x** – linear and quadratic equations exactly (`x² + 2x − 4 = 0 ⇒ x = −1 ± √5`), higher degrees exactly where possible (`x³ = 2 ⇒ x = ∛2`, `x⁴ − 5x² + 6 = 0 ⇒ x = ±√2, ±√3`), otherwise as rounded decimals (`x³ + x − 1 = 0 ⇒ x ≈ 0.682328`); with several variables, for each one that appears linearly. Equations with x in a denominator are solved with the common denominator; values that would make a denominator 0 are excluded and named (`x/(x − 1) = 1/(x − 1) ⇒ no solution (x = 1 excluded)`).
  - **Copy result**: the button at the end of each result row copies the result as shown (such as `y² − 16y + 64`) to the clipboard as plain text – for pasting into other apps. Clicking the row itself still inserts it after the selection.
- **Function graph**: select a term in x, such as `x² − 2` or `f(x) = 2x + 1`, and choose **Draw graph** in the text menu – a graph with axes, grid and marked zeros appears below. `/Function graph` inserts one too. The functions are edited below the graph: it changes while you type, **+ Function** adds up to six functions in their own colours (`sin(x)`, `cos`, `tan`, `exp`, `ln`, `abs`, `√` and `π` work). Dragging moves the view, **+**/**−** or <kbd>⌘</kbd>/<kbd>Ctrl</kbd> + scrolling zoom, **⟲** resets the view. On published pages the graph can be moved and zoomed but not changed.
- **Vectors**: write vectors as `(1 | 2 | 3)`, `(1; 2; 3)` or `(1, 2, 3)`. Flowplan calculates sums and multiples (`2 · (1; −2) − (3; 1) = (−1; −5)`), the **dot product** with `·` including the **angle** (`(1, 0) · (0, 1) = 0 ⇒ ∠ = 90°`), the **cross product** with `×` (`(1|0|0) × (0|1|0) = (0 | 0 | 1)`) and the **magnitude** with `|…|` (`|(1, 1)| = √2`). A vector selected on its own shows its magnitude and **unit vector** (`(3, 4) ⇒ v⁰ = (3/5, 4/5)`). **Draw vectors** in the text menu shows vectors in the plane as arrows in a coordinate system – for `(1, 2) + (3, 1)` both vectors and their sum. More vectors such as `(3, 2)` can be entered in the graph next to functions. **Vectors in space** such as `(1, 2, 3)` – cross products too – are drawn in a 3D coordinate system with x, y and z axes, a floor grid and dashed guides to the floor; **dragging turns the view**, and the view is saved with the page. The formula editor has the building blocks **Vector** (column vector), **Vector arrow** and **Cross product**; column vectors in formulas are calculated the same way.
- **In formulas**: the formula editor shows the same options under **Calculate** and appends the result in LaTeX, such as `\frac{3}{4} + \frac{1}{6} = \frac{11}{12}`.

## Dashboards and metrics

**/Metric** inserts a card with a number from a database, **/Dashboard** three side by side. With the gear you choose:

- the **database** (every database in the workspace you can read),
- optionally a **view** – then only the records its filters show count, such as “Open tickets”,
- the **calculation**: number of records, sum, average, minimum or maximum of a number, formula or rollup property,
- a **label**.

The server calculates the number for the person looking at the page and refreshes it every minute; private records only count for people allowed to see them. On published pages, visitors without access see a dash. Add charts by inserting a **linked database** below the metrics and choosing a chart view there – that makes a dashboard from several databases.