Adding a lexicon

.gitignore

@@ -4,3 +4,4 @@
 docs/images/.DS_Store
 docs/images/.DS_Store
 docs/images/.DS_Store
+docs/images/.DS_Store

docs/Cockpit.md

@@ -109,7 +109,7 @@ Resources are fonts, icons, other images, wallpapers, documentation, and texts u
 | Folder | Content                                                                                                                                                                                                  |
 | ------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
 | icons  | Folder containing all icon images for that aircraft. Images should be in JPEG or PNG format. Typical icon size is 256 × 256 pixels, RGB(A). Icons are named after their file name without the extension. |
-| fonts  | Folder containing all icon images for that aircraft. Images should be in JPEG or PNG format. Typical icon size is 256 × 256 pixels, RGB(A). Icons are named after their file name without the extension. |
+| fonts  | Folder containing all fonts for that aircraft. Fonts can be Truetype or Opentype. Fonts are named after their file name with the extension.                                                              |
 | docs   | Docs folder may contain documentation files, like explanatory images, and descriptive texts. Simpler text or markdown files are preferred.                                                               |
 | decks  | Cockpitdecks allow experienced users to add their own [[Web Decks]] specific to an aircraft.                                                                                                             |
 

docs/Extending/Internals/Observables.md

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+Observables are data that is constantly monitored. When the data matches some criteria, a list of actions or commands is executed.
+
+For people familiar with the concept, it can be considered a *if-this-then-that* instruction. For example: If the weather data from the simulator indicates rain is falling on the aircraft, we can set the windshield wipers automatically.
+
+Observables are defined at the aircraft level.
+
+# Definition
+
+The file `observables.yaml` is located in the `deckconfig/resources` folder of an aircraft. It is loaded on startup.
+
+```
+observables:
+  - name: example
+    trigger: onchange
+    dataref: some/dataref/to/check
+    actions:
+      - command: do/some/action
+        delay: 5
+```
+
+## Attribute
+
+### Observables
+
+The `observables` attribute is a list of individual observables.
+
+# Observable
+
+## Attributes
+
+### Trigger
+
+#### True/False Evaluation
+
+The `trigger` attribute of an observable is a single dataref or a formula that is evaluated each time a dataref mentioned in the formula changes. The result of a the formula is compared to 0, i.e. True (different from zero) or False (equal to zero).
+
+If the result of the formula is True, commands listed into the `actions` attributes are executed.
+
+#### Value Changed
+
+Another method to trigger the flow of action(s) is to select the *value changed* mode. Actions get executed as the value of the dataref or of the computation has changed.
+
+### Observable
+
+The observable is the data that is monitored. It can either be a single dataref or a formula.
+
+### Actions
+
+The `actions` attribute is a list of individual actions that gets carried out in sequence if the trigger attribute is True.
+
+# Action
+
+## Attributes
+
+An action as the same attribute as a command carried out by a button:
+
+- instruction
+- delay
+- condition

docs/Extending/Reference/Lexicon.md

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+# Button
+
+A button is a piece of a deck a user can use to provide some interaction.
+
+It can be a simple button to press, a small LCD button, an encoder to turn, or a touch screen that can be swiped with multiple fingers.
+
+# Deck
+
+A Deck is a piece of hardware connected to a computer to provide some input by means of buttons, encoders, cursors... A Deck also provide some feedback to the user through colored LED lights, small LCD icon screens, or by emitting sound and vibration.
+
+# Layout
+
+In Cockpitdecks, a Layout is a collection of pages that can be displayed on a deck. ON startup, a deck must tell Cockpitdecks which Layout it is going to use.
+
+# Cockpitdecks
+
+Cockpitdecks is the name of the application used to control decks connected to a computer.
+
+# Activation
+
+# Representation
+
+# Simulator
+
+# Simulator Data
+# Simulator Instruction
+
+# Event
+
+## Simulator Event
+
+## Deck Event
+
+# Dataref
+
+A Dataref is a simulator data inside the X-Plane flight simulator.
+
+# SimVar
+
+A SimVar is a simulator data from Flight Simulator. There are several types of SimVar. Please refer to the [Flight Simulator SDK](https://docs.flightsimulator.com/html/Introduction/SDK_Overview.htm) for more information.