Document info.json files

6 years ago · 432674781a
--- a/docs/hardware_keyboard_guidelines.md
+++ b/docs/hardware_keyboard_guidelines.md
@ -16,6 +16,94 @@ In an effort to keep the repo size down, we're no longer accepting images of any

 Any sort of hardware file (plate, case, pcb) can't be stored in qmk_firmware, but we have the [qmk.fm repo](https://github.com/qmk/qmk.fm) where such files (as well as in-depth info) can be stored and viewed on [qmk.fm](http://qmk.fm). Downloadable files are stored in `/<keyboard>/` (name follows the same format as above) which are served at `http://qmk.fm/<keyboard>/`, and pages are generated from `/_pages/<keyboard>/` which are served at the same location (.md files are generated into .html files through Jekyll). Check out the `lets_split` directory for an example.

 ## Keyboard Metadata

 As QMK grows so does the ecosystem surrounding QMK. To make it easier for projects in that ecosystem to tie into QMK as we make changes we are developing a metadata system to expose information about keyboards in QMK.

 You can create `info.json` files at every level under `qmk_firmware/keyboards/&lt;name&gt;` to specify this metadata. These files are combined, with more specific files overriding keys in less specific files. This means you do not need to duplicate your metadata information. For example, `qmk_firmware/keyboards/clueboard/info.json` specifies `manufacturer` and `maintainer`, while `qmk_firmware/keyboards/clueboard/66/info.json` specifies more specific information about Clueboard 66%.

 ### `info.json` Format

 The `info.json` file is a JSON formatted dictionary with the following keys available to be set. You do not have to set all of them, merely the keys that apply to your keyboard.

 * `keyboard_name`
  * A free-form text string describing the keyboard.
  * Example: `Clueboard 66%`
 * `manufacturer`
  * A free-form text string naming the manufacturer.
  * Example: `Clueboard`
 * `identifier`
  * The Vendor, Product, and Revision ID's joined by a :
  * Example: `c1ed:2370:0001`
 * `url`
  * A URL to the keyboard's product page, [QMK.fm/keyboards](https://qmk.fm/keyboards) page, or other page describing information about the keyboard.
 * `processor`
  * The MCU or CPU this keyboard uses.
  * Example: `atmega32u4` or `stm32f303`
 * `bootloader`
  * What bootloader this keyboard uses. Available options:
    * `atmel-dfu`
    * `kiibohd-dfu-util`
    * `lufa-dfu`
    * `qmk-dfu`
    * `stm32-dfu-util`
    * (FIXME: This list is incomplete.)
 * `maintainer`
  * GitHub username of the maintainer, or `qmk` for community maintained boards
 * `width`
  * Width of the board in Key Units
 * `height`
  * Height of the board in Key Units
 * `layouts`
  * Physical Layout representations. See the next section for more detail.

 #### Layout Format

 Within our `info.json` file the `layouts` portion of the dictionary contains several nested dictionaries. The outer layer consists of QMK layout macros, for example `LAYOUT_ansi` or `LAYOUT_iso`. Within each layout macro are keys for `width`, `height`, and `key_count`, each of which should be self-explanatory.

 * `width`
  * Optional: The width of the layout in Key Units
 * `height`
  * Optional: The height of the layout in Key Units
 * `key_count`
  * **Required**: The number of keys in this layout
 * `layout`
  * A list of Key Dictionaries describing the physical layout. See the next section for more details.

 #### Key Dictionary Format

 Each Key Dictionary in a layout describes the physical properties of a key. If you are familiar with the Raw Code for <http://keyboard-layout-editor.com> you will find many of the concepts the same. We re-use the same key names and layout choices wherever possible, but unlike keyboard-layout-editor each key is stateless, inheriting no properties from the keys that came before it.

 All key positions and rotations are specified in relation to the top-left corner of the keyboard, and the top-left corner of each key.

 * `X`
  * **Required**: The absolute position of the key in the horizontal axis, in Key Units.
 * `Y`
  * **Required**: The absolute position of the key in the vertical axis, in Key Units.
 * `W`
  * The width of the key, in Key Units. Ignored if `ks` is provided. Default: `1`
 * `H`
  * The height of the key, in Key Units. Ignored if `ks` is provided. Default: `1`
 * `R`
  * How many degrees clockwise to rotate the key.
 * `RX`
  * The absolute position of the point to rotate the key around in the horizontal axis. Default: `x`
 * `RY`
  * The absolute position of the point to rotate the key around in the vertical axis. Default: `y`
 * `KS`
  * Key Shape: define a polygon by providing a list of points, in Key Units. 
  * **Important**: These are relative to the top-left of the key, not absolute.
  * Example ISO Enter: `[ [0,0], [1.5,0], [1.5,2], [0.25,2], [0.25,1], [0,1], [0,0] ]`

 ### How Is The Metadata Exposed?

 This metadata is primarily used in two ways:

 * To allow web-based configurators to dynamically generate UI
 * To support the new `make keyboard:keymap:qmk` target, which bundles this metadata up with the firmware to allow QMK Toolbox to be smarter.

 Configurator authors can see the [QMK Compiler](https://docs.compile.qmk.fm/api_docs.html) docs for more information on using the JSON API.

 ## Non-production/handwired projects

 We're happy to accept any project that uses QMK, including prototypes and handwired ones, but we have a separate `/keyboards/handwired/` folder for them, so the main `/keyboards/` folder doesn't get overcrowded. If a prototype project becomes a production project at some point in the future, we'd be happy to move it to the main `/keyboards/` folder!