# Dashboards and panels

A dashboard is a grid of widgets bound to message names — the same names that
wire the graph. It is its own document rather than a set of nodes, so it reads
across flows without belonging to any of them, and a flow stays the logic it
was.

There is no second tool and no separate deployment. You build the panel next to
the thing feeding it.

## Building one

**Dashboards → New dashboard**, then drag widgets onto the grid from the widget
picker and bind each to a message.

Like flows, dashboards are drafts until you publish. A wall panel reads only
the published version, so a half-arranged page never reaches the wall.

On a phone the dashboard is read, not arranged: the grid stacks to one column
and dragging is off. Picking a widget and editing its settings still works.

## The widgets

### Display

| Widget | Binds to | Notes |
|---|---|---|
| **Value** | anything | a formatted reading with a unit and a precision |
| **Gauge** | `float`, `int` | min, max, unit |
| **Chart** | `float`, `int` | up to five series; see *Two kinds of chart* below |
| **Bar** | `float`, `int` | a reading, optionally nesting up to three inside it |
| **Icon** | numbers, booleans, weather strings | maps a value onto a glyph |
| **Text** | — | markdown you write; a label, a note, an instruction |
| **Agenda** | `list` | upcoming items, e.g. from a calendar connector |
| **Forecast** | `list` | a short outlook strip |
| **Notification** | `record` | title, body and severity — what an alert channel writes |
| **Clock** | — | the time, in a size a wall can read |

### Input

| Widget | Publishes | Notes |
|---|---|---|
| **Button** | a fixed value | one-shot: run it, open it, reset it |
| **Switch** | `bool` | on/off |
| **Slider** | `float`, `int` | min, max, step |
| **Input** | text or a number | free entry |
| **Dropdown** | one of a list | a mode, a scene, a preset |
| **Colour** | `[h, s, v]`, `[r, g, b]` or `"#rrggbb"` | a hue wheel with saturation and brightness, for an RGB fixture |

The colour wheel sends `[h, s, v]` by default — hue 0-360 degrees, saturation
and value 0-100 percent, which is what a DMX encoder expects — and its
**Sends** setting switches that to `[r, g, b]` (0-255 each) or to a
`"#rrggbb"` string, because fixtures differ. The first two bind a `list`
message, the third a `str`.

A control publishes the message it is bound to, exactly as a node would. On the
flow canvas it is drawn as a labelled endpoint feeding the nodes that read it,
so nobody has to guess where the value came from.

### Typed bindings

Widgets are type-checked against the message the same way ports are: a switch
takes a `bool`, a gauge takes a number, an agenda takes a `list`, a
notification takes a `record`. Bind one wrong and the editor says so rather
than drawing nothing. The same table is enforced on the server.

Charts are the exception worth knowing: because identity across five series is
carried by lightness alone, a chart with more than one series always draws a
legend.

## Two kinds of chart

**Live.** Bind up to five messages and the chart draws the engine's own ring
buffer of recent values, extended over the socket as new ones land. Nothing
else is involved. This is what you want for "the last few hours of the living
room".

**Querying.** The chart publishes a *request* — the window and resolution it
wants — exactly as a slider publishes a value, and draws the `series` some flow
answers with. What serves that request is the flow's business: typically a
small Python node that builds a Flux query, an InfluxDB node that runs it, and
another Python node that shapes the rows.

That indirection is the point. The widget never learns which database answered
it, so swapping the store is a change to one flow and nothing else. The answer
also states what it was computed for, so an answer to a different question is
ignored rather than two charts overwriting each other's picture.

## Showing one

- `/view/{name}` — a browser tab pointed at one dashboard. Needs an ordinary
  session.
- **Panels** — a named device that pairs instead of logging in. Below.

## Panels: hanging a screen on a wall

A wall tablet has no keyboard, so it pairs.

1. **Dashboards → Panels**, add a panel named after where it hangs, and tick
   the dashboards it shows. More than one and the screen draws a rail to switch
   between them.
2. Point the device's browser at the link the dialog shows. The device then
   displays a six-character code.
3. Type that code into the same panel's **Pair device** field. The line under
   it names what is holding the code — check it is the screen you just hung,
   because approving adopts whatever answered. The screen picks the credential
   up within a few seconds and never asks again.

What the screen holds is not a login. It reaches that panel's published
dashboards and the messages its own widgets read or publish, and nothing else —
a message no tile on it draws is refused in both directions.

It cannot be made strictly read-only, and that is honest rather than an
oversight: a querying chart publishes its request, and a control on a panel is
the reason you put one there.

Deleting the panel revokes the credential and the assignment together, which is
how you retire a device and what it showed. Unpairing revokes only the
credential: the panel, its dashboards and their arrangement stay exactly where
they are, and the screen falls back to asking for a new code — which is how you
swap the device out without rebuilding what hangs there.

!!! note "If the link is wrong"

    The pairing link is built from the installation's `FRONTEND_HOST`. If that
    is not the address devices on your network actually reach, fix the setting
    rather than the link: it is the same one password-reset mails and the OAuth
    metadata are built from.

### A screen somewhere you cannot reach

Another building, someone else's network, no route in. An installation
[enrolled with a portal](portal.md) shows a second link,
`https://hub.${DOMAIN}/i/{installation-id}/panel`, and the same three steps
work through it: the portal serves that one page without a session, forwards
the pairing calls down the tunnel, and mints the credential when you approve
the code. The pairing line then reads *via portal*.

The portal names the panel and nothing else. What the panel may read is decided
on the installation, on every call, by the same check a locally paired screen
passes. Two differences: it acts as the account the installation was enrolled
with rather than as whoever approved it, and deleting the panel stops it here
immediately while the portal's copy of the token expires on its own — which is
also why unpairing, which works on a credential this installation signed, does
not reach a remote screen. Revoke that one at the hub.

## See also

- [Payload types](../reference/payload-types.md) — what a widget can bind to
- [Flows, nodes and messages](../concepts/flows.md) — where the names come from
- [Accounts and the portal](portal.md) — reaching all of this from outside