runtime/doc/popup.txt

*popup.txt*  For Vim version 8.1.  Last change: 2019 May 26


		  VIM REFERENCE MANUAL    by Bram Moolenaar


Displaying text in floating window.			*popup* *popup-window*

THIS IS UNDER DESIGN - ANYTHING MAY STILL CHANGE  

1. Introduction			|popup-intro|
2. Functions			|popup-functions|
3. Examples			|popup-examples|


{not available if the |+eval| feature was disabled at compile time}
{not able to use text properties if the |+textprop| feature was disabled at
compile time}

==============================================================================
1. Introduction						*popup-intro*

We are talking about popup windows here, text that goes on top of the regular
windows and is under control of a plugin.  You cannot edit the text in the
popup window like with regular windows.

A popup window can be used for such things as:
- briefly show a message without overwriting the command line
- prompt the user with a dialog
- display contextual information while typing
- give extra information for auto-completion

The text in the popup window can be colored with |text-properties|.  It is
also possible to use syntax highlighting.

The default color used is "Pmenu".  If you prefer something else use the
"highlight" argument or the 'wincolor' option, e.g.: >
	hi MyPopupColor ctermbg=lightblue guibg=lightblue
	call setwinvar(winid, '&wincolor', 'MyPopupColor')

'hlsearch' and match highlighting are not displayed in a popup window.

A popup window has a window-ID like other windows, but behaves differently.
The size can be up to the whole Vim window and it overlaps other windows.
Popup windows can also overlap each other.

The popup window contains a buffer, and that buffer is always associated with
the popup window.  The window cannot be used in Normal, Visual or Insert mode,
it does not get keyboard focus.  You can use functions like `setbufline()` to
change the text in the buffer.  There are more differences from how this
window and buffer behave compared to regular windows and buffers, see
|popup-buffer|.

If this is not what you are looking for, check out other popup functionality:
- popup menu, see |popup-menu|
- balloon, see |balloon-eval|


WINDOW POSITION AND SIZE			*popup-position*

The height of the window is normally equal to the number of, possibly
wrapping, lines in the buffer.  It can be limited with the "maxheight"
property.  You can use empty lines to increase the height.

The width of the window is normally equal to the longest line in the buffer.
It can be limited with the "maxwidth" property.  You can use spaces to
increase the width.

By default the 'wrap' option is set, so that no text disappears.  However, if
there is not enough space, some text may be invisible.



TODO:

Example how to use syntax highlighting of a code snippet.

Scrolling: When the screen scrolls up for output of an Ex command, what
happens with popups?
1. Stay where they are.  Problem: listed text may go behind and can't be read.
2. Scroll with the page.  What if they get updated?  Either postpone, or take
   the scroll offset into account.
Probably 2. is the best choice.


IMPLEMENTATION:
- Code is in popupwin.c
- when creating the window set options to Vim default? (verify with 'number')
- Do not show tilde below last line.
- Implement filter.
  Check that popup_close() works in the filter.
- Handle screen resize in screenalloc().
- Make redrawing more efficient and avoid flicker.
    Fix redrawing problem with completion.
    Fix redrawing problem when scrolling non-current window
    Fix redrawing the statusline on top of a popup
- Properly figure out the size and position.
- Can the buffer be re-used, to avoid using up lots of buffer numbers?
- Implement all the unimplemented options and features.


==============================================================================
2. Functions						*popup-functions*

THIS IS UNDER DESIGN - ANYTHING MAY STILL CHANGE  

[functions to be moved to eval.txt later, keep overview of functions here]

popup_create({text}, {options})				*popup_create()*
		Open a popup window showing {text}, which is either:
		- a string
		- a list of strings
		- a list of text lines with text properties
		  	{not implemented yet}
		{options} is a dictionary with many possible entries.
		See |popup_create-usage| for details.

		Returns a window-ID, which can be used with other popup
		functions.  Use `winbufnr()` to get the number of the buffer
		in the window: >
			let winid = popup_create('hello', {})
			let bufnr = winbufnr(winid)
			call setbufline(bufnr, 2, 'second line')
<		In case of failure zero is returned.


popup_close({id})					*popup_close()*
		Close popup {id}.  The window and the associated buffer will
		be deleted.


popup_dialog({text}, {options})				*popup_dialog()*
	  	{not implemented yet}
		Just like |popup_create()| but with these default options: >
			call popup_create({text}, {
				\ 'pos': 'center',
				\ 'zindex': 200,
				\ 'border': [],
				\})
<		Use {options} to change the properties.


popup_notification({text}, {options})			 *popup_notification()*
	  	{not implemented yet}
		Show the {text} for 3 seconds at the top of the Vim window.
		This works like: >
			call popup_create({text}, {
				\ 'line': 1,
				\ 'col': 10,
				\ 'time': 3000,
				\ 'tab': -1,
				\ 'zindex': 200,
				\ 'highlight': 'WarningMsg',
				\ 'border': [],
				\ })
<		Use {options} to change the properties.


popup_atcursor({text}, {options})			 *popup_atcursor()*
	  	{not implemented yet}
		Show the {text} above the cursor, and close it when the cursor
		moves.  This works like: >
			call popup_create({text}, {
				\ 'line': 'cursor-1',
				\ 'col': 'cursor',
				\ 'moved': 'WORD',
				\ })
<		Use {options} to change the properties.


popup_menu({text}, {options})				 *popup_menu()*
	  	{not implemented yet}
		Show the {text} near the cursor, handle selecting one of the
		items with cursorkeys, and close it an item is selected with
		Space or Enter. {text} should have multiple lines to make this
		useful.  This works like: >
			call popup_create({text}, {
				\ 'pos': 'center',
				\ 'zindex': 200,
				\ 'wrap': 0,
				\ 'border': [],
				\ 'filter': 'popup_filter_menu',
				\ })
<		Use {options} to change the properties.  Should at least set
		"callback" to a function that handles the selected item.


popup_hide({id})						*popup_hide()*
		If {id} is a displayed popup, hide it now. If the popup has a
		filter it will not be invoked for so long as the popup is
		hidden.
		If window {id} does not exist nothing happens.  If window {id}
		exists but is not a popup window an error is given. *E993*

popup_show({id})						*popup_show()*
		If {id} is a hidden popup, show it now.
		For {id} see `popup_hide()`.

popup_move({id}, {options})					*popup_move()*
		Move popup {id} to the position speficied with {options}.
		{options} may contain the items from |popup_create()| that
		specify the popup position: "line", "col", "pos", "maxheight",
		"minheight", "maxwidth" and "minwidth".
		For {id} see `popup_hide()`.


popup_filter_menu({id}, {key})				*popup_filter_menu()*
	  	{not implemented yet}
		Filter that can be used for a popup. It handles the cursor
		keys to move the selected index in the popup. Space and Enter
		can be used to select an item.  Invokes the "callback" of the
		popup menu with the index of the selected line as the second
		argument.


popup_filter_yesno({id}, {key})				*popup_filter_yesno()*
	  	{not implemented yet}
		Filter that can be used for a popup. It handles only the keys
		'y', 'Y' and 'n' or 'N'.  Invokes the "callback" of the
		popup menu with the 1 for 'y' or 'Y' and zero for 'n' or 'N'
		as the second argument.  Pressing Esc and CTRL-C works like
		pressing 'n'.


popup_setoptions({id}, {options})			*popup_setoptions()*
	  	{not implemented yet}
		Override options in popup {id} with entries in {options}.


popup_getoptions({id})					*popup_getoptions()*
	  	{not implemented yet}
		Return the {options} for popup {id}.

popup_getposition({id})					*popup_getposition()*
		Return the position and size of popup {id}.  Returns a Dict
		with these entries:
			col	screen column of the popup, one-based
			line	screen line of the popup, one-based
			width	width of the popup in screen cells
			height	height of the popup in screen cells
		Note that these are the actual screen positions.  They differ
		from the values in `popup_getoptions()` for the sizing and
		positioning mechanism applied.
		If popup window {id} is not found an empty Dict is returned.


							*:popupclear* *:popupc*
:popupc[lear]	Emergency solution to a misbehaving plugin: close all popup
		windows.


POPUP BUFFER AND WINDOW					*popup-buffer*

A new buffer is created to hold the text and text properties of the popup
window.  The buffer is always associated with the popup window and
manipulation is restricted:
- the buffer has no name
- 'buftype' is "popup" 
- 'swapfile' is off
- 'bufhidden' is "hide"
- 'buflisted' is off
- 'undolevels' is -1: no undo at all
TODO: more

It is possible to change these options, but anything might break then, so
better leave them alone.

The window does have a cursor position, but the cursor is not displayed.

To execute a command in the context of the popup window and buffer use
`win_execute()`.  Example: >
	call win_execute(winid, 'syntax enable')

Options can be set on the window with `setwinvar()`, e.g.: >
	call setwinvar(winid, '&wrap', 0)
And options can be set on the buffer with `setbufvar()`, e.g.: >
	call setbufvar(winbufnr(winid), '&filetype', 'java')


POPUP_CREATE() ARGUMENTS				*popup_create-usage*

The first argument of |popup_create()| specifies the text to be displayed, and
optionally text properties.  It is in one of three forms:
- a string
- a list of strings
- a list of dictionaries, where each dictionary has these entries:
	text		String with the text to display.
	props		A list of text properties.  Optional.
			Each entry is a dictionary, like the third argument of
			|prop_add()|, but specifying the column in the
			dictionary with a "col" entry, see below:
			|popup-props|.

The second argument of |popup_create()| is a dictionary with options:
	line		screen line where to position the popup; can use
			"cursor", "cursor+1" or "cursor-1" to use the line of
			the cursor and add or subtract a number of lines;
			default is "cursor-1".
			{only number is implemented}
	col		screen column where to position the popup; can use
			"cursor" to use the column of the cursor, "cursor+99"
			and "cursor-99" to add or subtract a number of
			columns; default is "cursor"
			{only number is implemented}
	pos		"topleft", "topright", "botleft" or "botright":
			defines what corner of the popup "line" and "col" are
			used for.  Default is "botleft".  Alternatively
			"center" can be used to position the popup in the
			center of the Vim window.
			{not implemented yet}
	flip		when TRUE (the default) and the position is relative
			to the cursor, flip to below or above the cursor to
			avoid overlap with the |popupmenu-completion| or
			another popup with a higher "zindex"
			{not implemented yet}
	maxheight	maximum height
	minheight	minimum height
	maxwidth	maximum width
	minwidth	minimum width
	hidden		when TRUE the popup exists but is not displayed; use
			`popup_show()` to unhide it.
			{not implemented yet}
	tab		when -1: display the popup on all tabs; when 0 (the
			default): display the popup on the current tab;
			otherwise the number of the tab page the popup is
			displayed on; when invalid the current tab is used
			{only -1 and 0 are implemented}
	title		text to be displayed above the first item in the
			popup, on top of any border
			{not implemented yet}
	wrap		TRUE to make the lines wrap (default TRUE)
			{not implemented yet}
	highlight	highlight group name to use for the text, stored in
			the 'wincolor' option
	border		list with numbers, defining the border thickness
			above/right/below/left of the popup; an empty list
			uses a border of 1 all around
			{not implemented yet}
	borderhighlight	highlight group name to use for the border
			{not implemented yet}
	borderchars	list with characters, defining the character to use
			for the top/right/bottom/left border; optionally
			followed by the character to use for the
			topright/botright/botleft/topleft corner; an empty
			list can be used to show a double line all around
			{not implemented yet}
	zindex		priority for the popup, default 50
	time		time in milliseconds after which the popup will close;
			when omitted |popup_close()| must be used.
	moved		"cell": close the popup if the cursor moved at least
			one screen cell; "word" allows for moving within
			|<cword>|, "WORD" allows for moving within |<cWORD>|,
			a list with two numbers specifies the start and end
			column
			{not implemented yet}
	filter		a callback that can filter typed characters, see 
			|popup-filter|
			{not implemented yet}
	callback	a callback to be used when the popup closes, e.g. when
			using |popup_filter_menu()|, see |popup-callback|.
			{not implemented yet}

Depending on the "zindex" the popup goes under or above other popups.  The
completion menu (|popup-menu|) has zindex 100.  For messages that occur for a
short time the suggestion is to use zindex 1000.

By default text wraps, which causes a line in {lines} to occupy more than one
screen line.  When "wrap" is FALSE then the text outside of the popup or
outside of the Vim window will not be displayed, thus truncated.


POPUP TEXT PROPERTIES					*popup-props*

These are similar to the third argument of |prop_add()| except:
- "lnum" is always the current line in the list
- "bufnr" is always the buffer of the popup
- "col" is in the Dict instead of a separate argument
- "transparent" is extra
So we get:
	col		starting column, counted in bytes, use one for the
			first column.
	length		length of text in bytes; can be zero
	end_lnum	line number for the end of the text
	end_col		column just after the text; not used when "length" is
			present; when {col} and "end_col" are equal, this is a
			zero-width text property
	id		user defined ID for the property; when omitted zero is
			used
	type		name of the text property type, as added with
			|prop_type_add()|
	transparent	do not show these characters, show the text under it;
			if there is an border character to the right or below
			it will be made transparent as well
			{not implemented yet}


POPUP FILTER						*popup-filter*

{not implemented yet}
A callback that gets any typed keys while a popup is displayed.  The filter is
not invoked when the popup is hidden.

The filter can return TRUE to indicate the key has been handled and is to be
discarded, or FALSE to let Vim handle the key as usual in the current state.
In case it returns FALSE and there is another popup window visible, that
filter is also called.  The filter of the popup window with the highest zindex
is called first.

The filter function is called with two arguments: the ID of the popup and the
key.

Some common key actions:
	Esc		close the popup
	cursor keys	select another entry
	Tab		accept current suggestion

A mouse click arrives as <LeftMouse>.  The coordinates are in
v:mouse_popup_col and v:mouse_popup_row.  The top-left screen cell of the
popup is col 1, row 1 (not counting the border).

Vim provides standard filters |popup_filter_menu()| and
|popup_filter_yesno()|.


POPUP CALLBACK						*popup-callback*

{not implemented yet}
A callback that is invoked when the popup closes.  Used by
|popup_filter_menu()|.  Invoked with two arguments: the ID of the popup and
the result, which would usually be an index in the popup lines, or whatever
the filter wants to pass.

==============================================================================
3. Examples						*popup-examples*

TODO

Prompt the user to press y/Y or n/N: >

	func MyDialogHandler(id, result)
	   if a:result
	      " ... 'y' or 'Y' was pressed
	   endif
	endfunc

	call popup_create(['Continue? y/n'], {
		\ 'filter': 'popup_filter_yesno',
		\ 'callback': 'MyDialogHandler',
		\ })
<

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