[Docs] Improve Unicode documentation (#8676)

1 files changed, 91 insertions, 68 deletions

diff --git a/docs/feature_unicode.md b/docs/feature_unicode.md
index aedffe4ea..02a7bea5d 100644
--- a/docs/feature_unicode.md
+++ b/docs/feature_unicode.md
@@ -2,11 +2,25 @@
 
 Unicode characters can be input straight from your keyboard! There are some limitations, however.
 
-QMK has three different methods for enabling Unicode input and defining keycodes:
+In order to enable Unicode support on your keyboard, you will need to do the following:
 
-## Basic Unicode
+1. Choose one of three supported Unicode implementations: [Basic Unicode](#basic-unicode), [Unicode Map](#unicode-map), [UCIS](#ucis).
+2. Find which [input mode](#input-modes) is the best match for your operating system and setup.
+3. [Set](#setting-the-input-mode) the appropriate input mode (or modes) in your configuration.
+4. Add Unicode keycodes to your keymap.
 
-This method supports Unicode code points up to `0x7FFF`. This covers characters for most modern languages, as well as symbols, but it doesn't cover emoji.
+
+## 1. Methods :id=methods
+
+QMK supports three different methods for enabling Unicode input and adding Unicode characters to your keymap. Each has its pros and cons in terms of flexibility and ease of use. Choose the one that best fits your use case.
+
+The Basic method should be enough for most users. However, if you need a wider range of supported characters (including emoji, rare symbols etc.), you should use Unicode Map.
+
+<br>
+
+### 1.1. Basic Unicode :id=basic-unicode
+
+The easiest to use method, albeit somewhat limited. It stores Unicode characters as keycodes in the keymap itself, so it only supports code points up to `0x7FFF`. This covers characters for most modern languages (including East Asian), as well as symbols, but it doesn't cover emoji.
 
 Add the following to your `rules.mk`:
 
@@ -14,11 +28,13 @@ Add the following to your `rules.mk`:
 UNICODE_ENABLE = yes
 ```
 
-Then add `UC(c)` keycodes to your keymap, where _c_ is the code point (preferably in hexadecimal, up to 4 digits long). For example: `UC(0x45B)`, `UC(0x30C4)`.
+Then add `UC(c)` keycodes to your keymap, where _c_ is the code point of the desired character (preferably in hexadecimal, up to 4 digits long). For example, `UC(0x40B)` will output [Ћ](https://unicode-table.com/en/040B/), and `UC(0x30C4)` will output [ツ](https://unicode-table.com/en/30C4).
 
-## Unicode Map
+<br>
 
-This method supports all possible code points (up to `0x10FFFF`); however, you need to maintain a separate mapping table in your keymap file, which may contain at most 16384 entries.
+### 1.2. Unicode Map :id=unicode-map
+
+In addition to standard character ranges, this method also covers emoji, ancient scripts, rare symbols etc. In fact, all possible code points (up to `0x10FFFF`) are supported. Here, Unicode characters are stored in a separate mapping table. You need to maintain a `unicode_map` array in your keymap file, which may contain at most 16384 entries.
 
 Add the following to your `rules.mk`:
 
@@ -26,7 +42,7 @@ Add the following to your `rules.mk`:
 UNICODEMAP_ENABLE = yes
 ```
 
-Then add `X(i)` keycodes to your keymap, where _i_ is an array index into the mapping table:
+Then add `X(i)` keycodes to your keymap, where _i_ is the desired character's index in the mapping table. This can be a numeric value, but it's recommended to keep the indices in an enum and access them by name.
 
 ```c
 enum unicode_names {
@@ -44,15 +60,17 @@ const uint32_t PROGMEM unicode_map[] = {
 
 Then you can use `X(BANG)`, `X(SNEK)` etc. in your keymap.
 
-### Lower and Upper Case
+#### Lower and Upper Case
 
 Characters often come in lower and upper case pairs, such as å and Å. To make inputting these characters easier, you can use `XP(i, j)` in your keymap, where _i_ and _j_ are the mapping table indices of the lower and upper case character, respectively. If you're holding down Shift or have Caps Lock turned on when you press the key, the second (upper case) character will be inserted; otherwise, the first (lower case) version will appear.
 
 This is most useful when creating a keymap for an international layout with special characters. Instead of having to put the lower and upper case versions of a character on separate keys, you can have them both on the same key by using `XP()`. This helps blend Unicode keys in with regular alphas.
 
-Due to keycode size constraints, _i_ and _j_ can each only refer to one of the first 128 characters in your `unicode_map`. In other words, 0 ≤ _i_ ≤ 127 and 0 ≤ _j_ ≤ 127. This is enough for most use cases, but if you'd like to customize the index calculation, you can override the [`unicodemap_index()`](https://github.com/qmk/qmk_firmware/blob/71f640d47ee12c862c798e1f56392853c7b1c1a8/quantum/process_keycode/process_unicodemap.c#L40) function. This also allows you to, say, check Ctrl instead of Shift/Caps.
+Due to keycode size constraints, _i_ and _j_ can each only refer to one of the first 128 characters in your `unicode_map`. In other words, 0 ≤ _i_ ≤ 127 and 0 ≤ _j_ ≤ 127. This is enough for most use cases, but if you'd like to customize the index calculation, you can override the [`unicodemap_index()`](https://github.com/qmk/qmk_firmware/blob/71f640d47ee12c862c798e1f56392853c7b1c1a8/quantum/process_keycode/process_unicodemap.c#L36) function. This also allows you to, say, check Ctrl instead of Shift/Caps.
+
+<br>
 
-## UCIS
+### 1.3. UCIS :id=ucis
 
 This method also supports all possible code points. As with the Unicode Map method, you need to maintain a mapping table in your keymap file. However, there are no built-in keycodes for this feature — you have to create a custom keycode or function that invokes this functionality.
 
@@ -77,7 +95,7 @@ By default, each table entry may be up to 3 code points long. This number can be
 
 To use UCIS input, call `qk_ucis_start()`. Then, type the mnemonic for the character (such as "rofl") and hit Space, Enter or Esc. QMK should erase the "rofl" text and insert the laughing emoji.
 
-### Customization
+#### Customization
 
 There are several functions that you can define in your keymap to customize the functionality of this feature.
 
@@ -87,7 +105,8 @@ There are several functions that you can define in your keymap to customize the
 
 You can find the default implementations of these functions in [`process_ucis.c`](https://github.com/qmk/qmk_firmware/blob/master/quantum/process_keycode/process_ucis.c).
 
-## Input Modes
+
+## 2. Input Modes :id=input-modes
 
 Unicode input in QMK works by inputting a sequence of characters to the OS, sort of like a macro. Unfortunately, the way this is done differs for each platform. Specifically, each platform requires a different combination of keys to trigger Unicode input. Therefore, a corresponding input mode has to be set in QMK.
 
@@ -96,54 +115,67 @@ The following input modes are available:
 * **`UC_MAC`**: macOS built-in Unicode hex input. Supports code points up to `0x10FFFF` (all possible code points).
 
   To enable, go to _System Preferences > Keyboard > Input Sources_, add _Unicode Hex Input_ to the list (it's under _Other_), then activate it from the input dropdown in the Menu Bar.
-  By default, this mode uses the left Option key (`KC_LALT`) for Unicode input, but this can be changed by defining [`UNICODE_KEY_MAC`](#input-key-configuration) with another keycode.
+  By default, this mode uses the left Option key (`KC_LALT`) for Unicode input, but this can be changed by defining [`UNICODE_KEY_MAC`](#input-key-configuration) with a different keycode.
 
-  !> Using the _Unicode Hex Input_ input source may disable some Option based shortcuts, such as Option + Left Arrow and Option + Right Arrow.
+  !> Using the _Unicode Hex Input_ input source may disable some Option-based shortcuts, such as Option+Left and Option+Right.
 
-  !> `UC_OSX` is a deprecated alias of `UC_MAC` that will be removed in a future version of QMK.
+  !> `UC_OSX` is a deprecated alias of `UC_MAC` that will be removed in future versions of QMK. All new keymaps should use `UC_MAC`.
 
 * **`UC_LNX`**: Linux built-in IBus Unicode input. Supports code points up to `0x10FFFF` (all possible code points).
 
   Enabled by default and works almost anywhere on IBus-enabled distros. Without IBus, this mode works under GTK apps, but rarely anywhere else.
-  By default, this mode uses Ctrl+Shift+U (`LCTL(LSFT(KC_U))`) to start Unicode input, but this can be changed by defining [`UNICODE_KEY_LNX`](#input-key-configuration) with another keycode. This might be required for IBus versions ≥1.5.15, where Ctrl+Shift+U behavior is consolidated into Ctrl+Shift+E.
+  By default, this mode uses Ctrl+Shift+U (`LCTL(LSFT(KC_U))`) to start Unicode input, but this can be changed by defining [`UNICODE_KEY_LNX`](#input-key-configuration) with a different keycode. This might be required for IBus versions ≥1.5.15, where Ctrl+Shift+U behavior is consolidated into Ctrl+Shift+E.
 
 * **`UC_WIN`**: _(not recommended)_ Windows built-in hex numpad Unicode input. Supports code points up to `0xFFFF`.
 
-  To enable, create a registry key under `HKEY_CURRENT_USER\Control Panel\Input Method\EnableHexNumpad` of type `REG_SZ` called `EnableHexNumpad` and set its value to `1`. This can be done from the Command Prompt by running `reg add "HKCU\Control Panel\Input Method" -v EnableHexNumpad -t REG_SZ -d 1` with administrator privileges. Reboot afterwards.
+  To enable, create a registry key under `HKEY_CURRENT_USER\Control Panel\Input Method` of type `REG_SZ` called `EnableHexNumpad` and set its value to `1`. This can be done from the Command Prompt by running `reg add "HKCU\Control Panel\Input Method" -v EnableHexNumpad -t REG_SZ -d 1` with administrator privileges. Reboot afterwards.
   This mode is not recommended because of reliability and compatibility issues; use the `UC_WINC` mode instead.
 
 * **`UC_BSD`**: _(non implemented)_ Unicode input under BSD. Not implemented at this time. If you're a BSD user and want to help add support for it, please [open an issue on GitHub](https://github.com/qmk/qmk_firmware/issues).
 
 * **`UC_WINC`**: Windows Unicode input using [WinCompose](https://github.com/samhocevar/wincompose). As of v0.9.0, supports code points up to `0x10FFFF` (all possible code points).
 
-  To enable, install the [latest release](https://github.com/samhocevar/wincompose/releases/latest). Once installed, WinCompose will automatically run on startup. Works reliably under all version of Windows supported by the app.
-  By default, this mode uses right Alt (`KC_RALT`) as the Compose key, but this can be changed in the WinCompose settings and by defining [`UNICODE_KEY_WINC`](#input-key-configuration) with another keycode.
+  To enable, install the [latest release](https://github.com/samhocevar/wincompose/releases/latest). Once installed, WinCompose will automatically run on startup. This mode works reliably under all version of Windows supported by the app.
+  By default, this mode uses right Alt (`KC_RALT`) as the Compose key, but this can be changed in the WinCompose settings and by defining [`UNICODE_KEY_WINC`](#input-key-configuration) with a different keycode.
+
 
-### Switching Input Modes
+## 3. Setting the Input Mode :id=setting-the-input-mode
 
-There are two ways to set the input mode for Unicode: by keycode or by function. Keep in mind that both methods write to persistent storage (EEPROM), and are loaded each time the keyboard starts. So once you've set it the first time, you don't need to set it again unless you want to change it, or you've reset the EEPROM settings.
+To set your desired input mode, add the following define to your `config.h`:
 
-You can switch the input mode at any time by using one of the following keycodes. The easiest way is to add the ones you use to your keymap.
+```c
+#define UNICODE_SELECTED_MODES UC_LNX
+```
 
-|Keycode               |Alias    |Input Mode  |Description                                                   |
-|----------------------|---------|------------|--------------------------------------------------------------|
-|`UNICODE_MODE_FORWARD`|`UC_MOD` |Next in list|[Cycle](#input-mode-cycling) through selected modes           |
-|`UNICODE_MODE_REVERSE`|`UC_RMOD`|Prev in list|[Cycle](#input-mode-cycling) through selected modes in reverse|
-|`UNICODE_MODE_MAC`    |`UC_M_MA`|`UC_MAC`    |Switch to macOS input                                         |
-|`UNICODE_MODE_LNX`    |`UC_M_LN`|`UC_LNX`    |Switch to Linux input                                         |
-|`UNICODE_MODE_WIN`    |`UC_M_WI`|`UC_WIN`    |Switch to Windows input                                       |
-|`UNICODE_MODE_BSD`    |`UC_M_BS`|`UC_BSD`    |Switch to BSD input (not implemented)                         |
-|`UNICODE_MODE_WINC`   |`UC_M_WC`|`UC_WINC`   |Switch to Windows input using WinCompose                      |
+This example sets the board's default input mode to `UC_LNX`. You can replace this with `UC_MAC`, `UC_WINC`, or any of the other modes listed [above](#input-modes). The board will automatically use the selected mode on startup, unless you manually switch to another mode (see [below](#keycodes)).
 
-You can also switch the input mode by calling `set_unicode_input_mode(x)` in your code, where _x_ is one of the above input mode constants (e.g. `UC_LNX`). Since the function only needs to be called once, it's recommended that you do it in `eeconfig_init_user()` (or a similar function). For example:
+You can also select multiple input modes, which allows you to easily cycle through them using the `UC_MOD`/`UC_RMOD` keycodes.
 
 ```c
-void eeconfig_init_user(void) {
-    set_unicode_input_mode(UC_LNX);
-}
+#define UNICODE_SELECTED_MODES UC_MAC, UC_LNX, UC_WINC
 ```
 
-### Audio Feedback
+Note that the values are separated by commas. The board will remember the last used input mode and will continue using it on next power-up. You can disable this and force it to always start with the first mode in the list by adding `#define UNICODE_CYCLE_PERSIST false` to your `config.h`.
+
+#### Keycodes
+
+You can switch the input mode at any time by using the following keycodes. Adding these to your keymap allows you to quickly switch to a specific input mode, including modes not listed in `UNICODE_SELECTED_MODES`.
+
+|Keycode               |Alias    |Input Mode  |Description                                                                  |
+|----------------------|---------|------------|-----------------------------------------------------------------------------|
+|`UNICODE_MODE_FORWARD`|`UC_MOD` |Next in list|Cycle through selected modes, reverse direction when Shift is held           |
+|`UNICODE_MODE_REVERSE`|`UC_RMOD`|Prev in list|Cycle through selected modes in reverse, forward direction when Shift is held|
+|`UNICODE_MODE_MAC`    |`UC_M_MA`|`UC_MAC`    |Switch to macOS input                                                        |
+|`UNICODE_MODE_LNX`    |`UC_M_LN`|`UC_LNX`    |Switch to Linux input                                                        |
+|`UNICODE_MODE_WIN`    |`UC_M_WI`|`UC_WIN`    |Switch to Windows input                                                      |
+|`UNICODE_MODE_BSD`    |`UC_M_BS`|`UC_BSD`    |Switch to BSD input _(not implemented)_                                      |
+|`UNICODE_MODE_WINC`   |`UC_M_WC`|`UC_WINC`   |Switch to Windows input using WinCompose                                     |
+
+You can also switch the input mode by calling `set_unicode_input_mode(x)` in your code, where _x_ is one of the above input mode constants (e.g. `UC_LNX`).
+
+?> Using `UNICODE_SELECTED_MODES` is preferable to calling `set_unicode_input_mode()` in `matrix_init_user()` or similar functions, since it's better integrated into the Unicode system and has the added benefit of avoiding unnecessary writes to EEPROM.
+
+#### Audio Feedback
 
 If you have the [Audio feature](feature_audio.md) enabled on the board, you can set melodies to be played when you press the above keys. That way you can have some audio feedback when switching input modes.
 
@@ -157,20 +189,21 @@ For instance, you can add these definitions to your `config.h` file:
 #define UNICODE_SONG_WINC UNICODE_WINDOWS
 ```
 
-### Additional Customization
+
+## Additional Customization
 
 Because Unicode is a large and versatile feature, there are a number of options you can customize to make it work better on your system.
 
-#### Start and Finish Input Functions
+### Start and Finish Input Functions
 
 The functions for starting and finishing Unicode input on your platform can be overridden locally. Possible uses include customizing input mode behavior if you don't use the default keys, or adding extra visual/audio feedback to Unicode input.
 
-* `void unicode_input_start(void)` – This sends the initial sequence that tells your platform to enter Unicode input mode. For example, it presses Ctrl+Shift+U on Linux and holds the Option key on macOS.
-* `void unicode_input_finish(void)` – This is called to exit Unicode input mode, for example by pressing Space or releasing the Option key.
+* `void unicode_input_start(void)` – This sends the initial sequence that tells your platform to enter Unicode input mode. For example, it holds the left Alt key followed by Num+ on Windows, and presses the `UNICODE_KEY_LNX` combination (default: Ctrl+Shift+U) on Linux.
+* `void unicode_input_finish(void)` – This is called to exit Unicode input mode, for example by pressing Space or releasing the Alt key.
 
 You can find the default implementations of these functions in [`process_unicode_common.c`](https://github.com/qmk/qmk_firmware/blob/master/quantum/process_keycode/process_unicode_common.c).
 
-#### Input Key Configuration
+### Input Key Configuration
 
 You can customize the keys used to trigger Unicode input for macOS, Linux and WinCompose by adding corresponding defines to your `config.h`. The default values match the platforms' default settings, so you shouldn't need to change this unless Unicode input isn't working, or you want to use a different key (e.g. in order to free up left or right Alt).
 
@@ -180,54 +213,47 @@ You can customize the keys used to trigger Unicode input for macOS, Linux and Wi
 |`UNICODE_KEY_LNX` |`uint16_t`|`LCTL(LSFT(KC_U))`|`#define UNICODE_KEY_LNX  LCTL(LSFT(KC_E))`|
 |`UNICODE_KEY_WINC`|`uint8_t` |`KC_RALT`         |`#define UNICODE_KEY_WINC KC_RGUI`         |
 
-#### Input Mode Cycling
 
-You can choose which input modes are available for cycling through. By default, this is disabled. If you want to enable it, limiting it to just the modes you use makes sense. Note that the values in the list are comma-delimited.
+## Sending Unicode Strings
 
-```c
-#define UNICODE_SELECTED_MODES UC_MAC, UC_LNX, UC_WIN, UC_WINC
-```
+QMK provides several functions that allow you to send Unicode input to the host programmatically:
 
-You can cycle through the selected modes by using the `UC_MOD`/`UC_RMOD` keycodes, or by calling `cycle_unicode_input_mode(offset)` in your code (`offset` is how many modes to move forward by, so +1 corresponds to `UC_MOD`).
+### `send_unicode_string()`
 
-By default, when the keyboard boots, it will initialize the input mode to the last one you used. You can disable this and make it start with the first mode in the list every time by adding the following to your `config.h`:
+This function is much like `send_string()`, but it allows you to input UTF-8 characters directly. It supports all code points, provided the selected input mode also supports it. Make sure your `keymap.c` file is formatted using UTF-8 encoding.
 
 ```c
-#define UNICODE_CYCLE_PERSIST false
+send_unicode_string("(ノಠ痊ಠ)ノ彡┻━┻");
 ```
 
-!> Using `UNICODE_SELECTED_MODES` means you don't have to initially set the input mode in `matrix_init_user()` (or a similar function); the Unicode system will do that for you on startup. This has the added benefit of avoiding unnecessary writes to EEPROM.
+Example uses include sending Unicode strings when a key is pressed, as described in [Macros](feature_macros.md).
 
-## `send_unicode_string()`
+### `send_unicode_hex_string()`
 
-This function is much like `send_string()` but allows you to input UTF-8 characters directly, and supports all code points (provided the selected input method also supports it). Make sure your `keymap.c` is formatted in UTF-8 encoding.
+Similar to `send_unicode_string()`, but the characters are represented by their Unicode code points, written in hexadecimal and separated by spaces. For example, the table flip above would be achieved with:
 
 ```c
-send_unicode_string("(ノಠ痊ಠ)ノ彡┻━┻");
+send_unicode_hex_string("0028 30CE 0CA0 75CA 0CA0 0029 30CE 5F61 253B 2501 253B");
 ```
 
-## `send_unicode_hex_string()`
+An easy way to convert your Unicode string to this format is to use [this site](https://r12a.github.io/app-conversion/) and take the result in the "Hex/UTF-32" section.
 
-Similar to `send_unicode_string()`, but the characters are represented by their code point values in ASCII, separated by spaces. For example, the table flip above would be achieved with:
 
-```c
-send_unicode_hex_string("0028 30CE 0CA0 75CA 0CA0 0029 30CE 5F61 253B 2501 253B");
-```
+## Additional Language Support
 
-An easy way to convert your Unicode string to this format is by using [this site](https://r12a.github.io/app-conversion/), and taking the result in the "Hex/UTF-32" section.
+In `quantum/keymap_extras`, you'll see various language files — these work the same way as the ones for alternative layouts such as Colemak or BÉPO. When you include one of these language headers, you gain access to keycodes specific to that language / national layout. Such keycodes are defined by a 2-letter country/language code, followed by an underscore and a 4-letter abbreviation of the character to which the key corresponds. For example, including `keymap_french.h` and using `FR_UGRV` in your keymap will output `ù` when typed on a system with a native French AZERTY layout.
 
-## Additional Language Support
+If the primary system layout you use on your machine is different from US ANSI, using these language-specific keycodes can help your QMK keymaps better match what will actually be output on the screen. However, keep in mind that these keycodes are just aliases for the corresponding default US keycodes under the hood, and that the HID protocol used by keyboards is itself inherently based on US ANSI.
 
-In `quantum/keymap_extras/`, you'll see various language files - these work the same way as the alternative layout ones do. Most are defined by their two letter country/language code followed by an underscore and a 4-letter abbreviation of its name. `FR_UGRV` which will result in a `ù` when using a software-implemented AZERTY layout. It's currently difficult to send such characters in just the firmware.
 
 ## International Characters on Windows
 
-### AutoHotkey allows Windows users to create custom hotkeys among others.
+### AutoHotkey
 
-The method does not require Unicode support in the keyboard itself but depends instead of [AutoHotkey](https://autohotkey.com) running in the background.
+The method does not require Unicode support in the keyboard itself but instead depends on [AutoHotkey](https://autohotkey.com) running in the background.
 
 First you need to select a modifier combination that is not in use by any of your programs.
-CtrlAltWin is not used very widely and should therefore be perfect for this.
+Ctrl+Alt+Win is not used very widely and should therefore be perfect for this.
 There is a macro defined for a mod-tab combo `LCAG_T`.
 Add this mod-tab combo to a key on your keyboard, e.g.: `LCAG_T(KC_TAB)`.
 This makes the key behave like a tab key if pressed and released immediately but changes it to the modifier if used with another key.
@@ -242,8 +268,5 @@ AutoHotkey inserts the Text right of `Send, ` when this combination is pressed.
 
 ### US International
 
-If you enable the US International layout on the system, it will use punctuation to accent the characters.
-
-For instance, typing "\`a" will result in à.
-
+If you enable the US International layout on the system, it will use punctuation to accent the characters. For instance, typing "\`a" will result in à.
 You can find details on how to enable this [here](https://support.microsoft.com/en-us/help/17424/windows-change-keyboard-layout).