neovim/runtime/doc/ui.txt

*ui.txt*	Nvim


		 NVIM REFERENCE MANUAL    by Thiago de Arruda


UI protocol					     *ui*

				      Type <M-]> to see the table of contents.

==============================================================================
Introduction							     *ui-intro*

GUIs can be implemented as external processes communicating with Nvim over the
RPC API. The UI model consists of a terminal-like grid with a single,
monospace font size. Some elements (UI "widgets") can be drawn separately from
the grid ("externalized").

								    *ui-options*
After connecting to Nvim (usually a spawned, embedded instance) use the
|nvim_ui_attach| API method to tell Nvim that your program wants to draw the
Nvim screen grid with a size of width × height cells. `options` must be
a dictionary with these (optional) keys:
	`rgb`			Controls what color format to use.
				Set to true (default) to use 24-bit rgb
				colors.
				Set to false to use terminal color codes (at
				most 256 different colors).
	`ext_popupmenu`		Externalize the popupmenu. |ui-popupmenu|
	`ext_tabline`		Externalize the tabline. |ui-tabline|
	`ext_cmdline`		Externalize the cmdline. |ui-cmdline|

Nvim will then send msgpack-rpc notifications, with the method name "redraw"
and a single argument, an array of screen update events.
Update events are tuples whose first element is the string name of the update
kind. The rest are parameters for each update, described in the sections below.
These should be processed in order. Preferably the user should only be able to
see the screen state after all update events in the same "redraw" event are
processed (not any intermediate state after processing only a part of the
array).

Section 2 and 3 describes grid and mode events that are send unconditionally,
and suffice to implement a terminal-like interface. Nvim also allows a number
of screen elements to be sent as descriptive events for the GUI to draw
itself, rather than Nvim drawing itself on the grid. This is controlled by the
`ext_` options.

Future versions of Nvim may add new update kinds and may append new parameters
to existing update kinds. Clients must be prepared to ignore such extensions
to be forward-compatible. |api-contract|

==============================================================================
Global Events							    *ui-global*

["set_title", title]
["set_icon", icon]
	Set the window title, and icon (minimized) window title, respectively.
	In windowing systems not distinguishing between the two, "set_icon"
	can be ignored.

["mode_info_set", cursor_style_enabled, mode_info]
	`cursor_style_enabled` is a boolean indicating if the UI should set
	the cursor style. `mode_info` is a list of mode property maps. The
	current mode is given by the `mode_idx` field of the `mode_change`
	event.

Each mode property map may contain these keys:
	KEY		DESCRIPTION ~
	`cursor_shape`:	"block", "horizontal", "vertical"
	`cell_percentage`: Cell % occupied by the cursor.
	`blinkwait`, `blinkon`, `blinkoff`: See |cursor-blinking|.
	`hl_id`:	Cursor highlight group.
	`hl_lm`:	Cursor highlight group if 'langmap' is active.
	`short_name`:	Mode code name, see 'guicursor'.
	`name`:		Mode descriptive name.
	`mouse_shape`:	(To be implemented.)

Some keys are missing in some modes.

["mode_change", mode, mode_idx]
	The mode changed.  The first parameter `mode` is a string representing
	the current mode. `mode_idx` is an index into the array received in
	the `mode_info_set` event. UIs should change the cursor style
	according to the properties specified in the corresponding item. The
	set of modes reported will change in new versions of Nvim, for
	instance more submodes and temporary states might be represented as
	separate modes.


["mouse_on"]
["mouse_off"]
	Tells the client whether mouse support, as determined by |'mouse'|
	option, is considered to be active in the current mode. This is mostly
	useful for a terminal frontend, or other situations where nvim mouse
	would conflict with other usages of the mouse. It is safe for a client
	to ignore this and always send mouse events.

["busy_on"]
["busy_off"]
	Nvim started or stopped being busy, and possibly not responsible to user
	input. This could be indicated to the user by hiding the cursor.

["suspend"]
	|:suspend| command or |Ctrl-Z| mapping is used. A terminal client (or other
	client where it makes sense) could suspend itself.  Other clients can
	safely ignore it.

["update_menu"]
	The menu mappings changed.

["bell"]
["visual_bell"]
	Notify the user with an audible or visual bell, respectively.

==============================================================================
Grid Events							      *ui-grid*

["resize", width, height]
	The grid is resized to `width` and `height` cells.

["clear"]
	Clear the grid.

["eol_clear"]
	Clear from the cursor position to the end of the current line.

["cursor_goto", row, col]
	Move the cursor to position (row, col). Currently, the same cursor is
	used to define the position for text insertion and the visible cursor.
	However, only the last cursor position, after processing the entire
	array in the "redraw" event, is intended to be a visible cursor
	position.

["update_fg", color]
["update_bg", color]
["update_sp", color]
	Set the default foreground, background and special colors
	respectively.

							*ui-event-highlight_set*
["highlight_set", attrs]
	Set the attributes that the next text put on the grid will have.
	`attrs` is a dict with the keys below. Any absent key is reset
	to its default value. Color defaults are set by the `update_fg` etc
	updates. All boolean keys default to false.

	`foreground`:	foreground color.
	`background`:	backround color.
	`special`:	color to use for underline and undercurl, when present.
	`reverse`:	reverse video. Foreground and background colors are
			switched.
	`italic`:	italic text.
	`bold`:		bold text.
	`underline`:	underlined text. The line has `special` color.
	`undercurl`:	undercurled text. The curl has `special` color.

["put", text]
	The (utf-8 encoded) string `text` is put at the cursor position
	(and the cursor is advanced), with the highlights as set by the
	last `highlight_set` update.

["set_scroll_region", top, bot, left, right]
	Define the scroll region used by `scroll` below.

["scroll", count]
	Scroll the text in the scroll region. The diagrams below illustrate
	what will happen, depending on the scroll direction. "=" is used to
	represent the SR(scroll region) boundaries and "-" the moved rectangles.
	Note that dst and src share a common region.

	If count is bigger than 0, move a rectangle in the SR up, this can
	happen while scrolling down.
>
		+-------------------------+
		| (clipped above SR)      |            ^
		|=========================| dst_top    |
		| dst (still in SR)       |            |
		+-------------------------+ src_top    |
		| src (moved up) and dst  |            |
		|-------------------------| dst_bot    |
		| src (cleared)           |            |
		+=========================+ src_bot
<
	If count is less than zero, move a rectangle in the SR down, this can
	happen while scrolling up.
>
		+=========================+ src_top
		| src (cleared)           |            |
		|------------------------ | dst_top    |
		| src (moved down) and dst|            |
		+-------------------------+ src_bot    |
		| dst (still in SR)       |            |
		|=========================| dst_bot    |
		| (clipped below SR)      |            v
		+-------------------------+
<
==============================================================================
Popupmenu Events						 *ui-popupmenu*

Only sent if `ext_popupmenu` option is set in |ui-options|

["popupmenu_show", items, selected, row, col]
	`items` is an array of the items to show, the
	items are themselves arrays of the form [word, kind, menu, info]
	as defined at |complete-items|, except that `word` is replaced by
	`abbr` if present.  `selected` is the initially selected item, either a
	zero-based index into the array of items, or -1 if no item is
	selected. `row` and `col` is the anchor position, where the first
	character of the completed word will be.

["popupmenu_select", selected]
	An item in the currently displayed popupmenu is selected. `selected`
	is either a zero-based index into the array of items from the last
	`popupmenu_show` event, or -1 if no item is selected.

["popupmenu_hide"]
	The popupmenu is hidden.

==============================================================================
Tabline Events							   *ui-tabline*

Only sent if `ext_tabline` option is set in |ui-options|

["tabline_update", curtab, tabs]
	Tabline was updated. UIs should present this data in a custom tabline
	widget.
	curtab:	  Current Tabpage
	tabs:	  List of Dicts [{ "tab": Tabpage, "name": String }, ...]

==============================================================================
Cmdline Events							   *ui-cmdline*

Only sent if `ext_cmdline` option is set in |ui-options|

["cmdline_show", content, pos, firstc, prompt, indent, level]
        content: List of [attrs, string]
	         [[{}, "t"], [attrs, "est"], ...]
	The `content` is the full content that should be displayed in the
	cmdline, and the `pos` is the position of the cursor that in the
	cmdline. This event will be triggered when you type in the cmdline.
	The content is divided into chunks with different highlight attributes
	represented as a dict, see |ui-event-highlight_set|.

	`firstc` and `prompt` are text, that if non-empty should be
	displayed in front of the command line. `firstc` always indicates
	built in command lines such as `:` (ex command) and `/` `?` (search),
	while `prompt` is an |input()| prompt. `indent` tells how many spaces
	the content should be indented

	The command line in nvim can be invoked recursively, for instance by
	typing `<c-r>=` at the command line prompt. The `level` field is used
	to distinguish different command lines active at the same time. The
	first invoked command line will always have level 1, and the next
	recursively invoked prompt will have level 2. Also, a command line
	invoked while in command line window will have a higher level than
	than the edited command line.

["cmdline_pos", pos, level]
	Change the cursor position in the cmdline.

["cmdline_special_char", c, shift, level]
	Display a special char in the cmdline at the cursor position. This is
	typically used to indicate a pending state, like right after Ctrl-V.
	if shift is true the text after the cursor should be shifted,
	otherwise it should overshadow the char at the cursor.
	Should be hidden at next cmdline_char

["cmdline_hide"]
	Hide the cmdline.

["cmdline_block_show", lines]
	Show a block of context to the current command line. This occurs for
	instance if a function is interactively defined at the command line.
	`lines` is a list of lines where each line is represented as a list of
	highlighted chunks, just like `contents` of |ui-event-cmdline_show|.

["cmdline_block_append", line]
	Append a line at the end of the currently shown block.

["cmdline_block_hide"]
	Hide the block.

==============================================================================
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