Screenshots: Fn+p on every screen (#83)

Fn+p saves the screen as it is to /screenshots, as the Shell's `screenshot`
does, from anywhere: text fields, dialogs and the help panel included. The
key never reaches an App.

It refuses on Settings > Debug Console, which shows the token: a picture of
that page is a copy of the token in a file (App::showsSecret). `key shot`
presses it over the consoles.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

site/content/dev/debug/commands.md

@@ -29,7 +29,7 @@ gnss quiet on|off   pause the GNSS receiver while the LoRa radio listens (it cos
 gnss status | gnss restart | gnss track start|stop | gnss nmea on|off | gnss send <sentence without $ and checksum>
 crash             the last crash: firmware, reason, task, backtrace
 coredump erase    forget the core dump in flash
-key <name|char>   press a key: up down left right select back home del tab space help, or one character; ctrl- alt- shift- before it (key ctrl-down)
+key <name|char>   press a key: up down left right select back home del tab space help shot, or one character; ctrl- alt- shift- before it (key ctrl-down)
 wifi status | wifi add <ssid><TAB><password>
 wifi ip <ssid> dhcp | wifi ip <ssid> <address>/<prefix> [gateway]   a Saved Network's IP setting
 wifi dns <a> [b] | wifi dns always on|off | wifi ntp <a> [b]   DNS and NTP servers
@@ -62,7 +62,7 @@ In **Safe Mode** (see [Crashes and Safe Mode](/dev/debug/crashes/)) only a few r
 | Command | Effect |
 |---|---|
 | `burst` | Publishes 5 Notifications at once |
-| `key up\|down\|left\|right\|select\|back\|home\|del\|tab\|space\|help`, or `key <char>` | Injects a key press (`help` is Fn+h: the keys of the screen that is showing). `ctrl-`, `alt-` and `shift-` before it hold that key: `key ctrl-down`, `key alt-up`, `key ctrl-b` |
+| `key up\|down\|left\|right\|select\|back\|home\|del\|tab\|space\|help\|shot`, or `key <char>` | Injects a key press (`help` is Fn+h: the keys of the screen that is showing; `shot` is Fn+p: a screenshot). `ctrl-`, `alt-` and `shift-` before it hold that key: `key ctrl-down`, `key alt-up`, `key ctrl-b` |
 | `sound on` / `sound off` | Toggles the Sound setting (beep + LED) |
 | `short` / `normal` | Screen timeouts 5 s / 10 s, or 30 s / 60 s |
 | `wifi add <ssid><TAB><password>` | Adds a Saved Network (so credentials stay out of the repo) |

site/content/dev/debug/drive-the-ui.md

@@ -11,7 +11,7 @@ Everything the keyboard can do, a command can do, and everything on the screen c
 ## Keys
 
 ```
-key up|down|left|right|select|back|home|del|tab|space|help
+key up|down|left|right|select|back|home|del|tab|space|help|shot
 key a        # any single character: it is typed
 ```
 

site/content/dev/milestones/u1.md

@@ -52,3 +52,18 @@ The lists first lived in each App's `help()`, as code. They are now **data, in o
 Three rows lost their second wording on the way, since a table is constant: GNSS's `Tab` and `r`, and the Scanner's `c`, now say both things they do ("record a Track, or stop it") instead of the one that applies. The guide pages keep their written tables too, where they say more than a key list can; those can still drift, and the generated ones under them are the reference.
 
 **Not checked:** the real Fn+h and `?` on the keyboard (the mapper is host-tested; the device was driven with `key help`); the Setup screens, which only a device that was never set up shows, so their new text has not been seen on a screen; and the states that need something to happen first (a dialog, a copy in progress, a Gemini prompt, a packet's details): their lists were read against the key handling, not looked at.
+
+## The screenshot key (issue #83)
+
+A screenshot could only be taken by typing `screenshot` in the Shell, where "now" is a picture of the Shell.
+
+- **Fn+p, on every screen**, text fields included, saves the screen as it is (a dialog, the help panel or a Toast if one is showing) as a PNG in `/screenshots`, the way the Shell's command does. A Toast says so once the file is written, so it is never in the picture.
+- **It never reaches an App.** `Key::Screenshot` comes out of the key mapper and is handled before the App manager, so the help panel stays open and a dialog keeps its selection.
+- **Not on Settings > Debug Console:** that page shows the token, and a picture of it is a copy of the token in a file. `App::showsSecret()` says so, and the key answers with a Toast instead.
+- **No card:** a Toast says so.
+- No setting to switch it off: Fn with a letter isn't pressed by accident.
+- It is in the "Everywhere" group of the help panel, and so in the website's key tables. `key shot` presses it over the consoles.
+
+**Checked on the device** (2026-10-07, with `key shot`): in the Launcher, a 33,383-byte PNG appears in `/screenshots` and is the Launcher; with the help panel open, the picture is of the panel (which now lists Fn p) and the panel stays open; on Settings > Debug Console, no file is written; back on the Settings list, one is. The test pictures were removed.
+
+**Not checked:** the real Fn+p on the keyboard (the mapper is host-tested); the two Toasts that refuse, which weren't looked at (one of them is on the page that mustn't be photographed); a device with no card.

site/content/guide/basics.md

@@ -26,6 +26,7 @@ The Cardputer's keyboard has no arrow keys and no Escape, so the firmware gives
 | <kbd>Fn</kbd> + <kbd>;</kbd> <kbd>.</kbd> <kbd>,</kbd> <kbd>/</kbd> | The arrows: up, down, left, right |
 | <kbd>;</kbd> <kbd>.</kbd> <kbd>,</kbd> <kbd>/</kbd> alone | The same arrows, as long as you are **not** typing text |
 | <kbd>Fn</kbd> + <kbd>h</kbd>, or <kbd>?</kbd> when not typing | **Help:** the keys of the screen you are on |
+| <kbd>Fn</kbd> + <kbd>p</kbd> | **A screenshot:** the screen as it is, saved as a picture in `/screenshots` on the SD card |
 | <kbd>Tab</kbd> | Switches view in an App that has more than one |
 | <kbd>Del</kbd> | Deletes backwards when you type |
 | <kbd>opt</kbd> then an accent, then a letter | Types an accented letter: <kbd>opt</kbd> <kbd>'</kbd> <kbd>e</kbd> gives é |

site/content/guide/shell.md

@@ -77,7 +77,7 @@ screenshot        the screen, now
 screenshot 5      the screen in 5 seconds: time to go to another App
 ```
 
-The picture is saved as a PNG in `/screenshots` on the SD card, named by date and time, and a Toast says so once it is written (so the Toast is never in the picture). From the Shell, "now" is always a picture of the Shell: use the pause to get to the screen you want. The [Storage App](/guide/storage/) shows the files; to look at them, take the card to a computer.
+The picture is saved as a PNG in `/screenshots` on the SD card, named by date and time, and a Toast says so once it is written (so the Toast is never in the picture). From the Shell, "now" is always a picture of the Shell: use the pause to get to the screen you want, or, simpler, press <kbd>Fn</kbd> + <kbd>p</kbd> on that screen: it takes the same picture from anywhere. The [Storage App](/guide/storage/) lists the files and [shows them](/guide/storage/#pictures).
 
 ## What it costs
 

site/data/keys.toml

@@ -9,6 +9,7 @@ rows = [
     ["Fn `", "home, the Launcher"],
     ["; . , /", "arrows (Fn+ while typing)"],
     ["Fn h  ?", "these keys (? not typing)"],
+    ["Fn p", "a screenshot, on the card"],
 ]
 
 [[scope]]