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popup.txt  For Vim version 8.1.  Last change: 2019 May 21


                  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 changing the command line
- prompt the user with a dialog
- display 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.

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.
It 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


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.

Positioning relative to the popup-menu to avoid overlapping with it; add a
function to get the position and size of the popup-menu.


IMPLEMENTATION:
- Put code in popupwin.c
- Use win_update() for displaying
- At first redraw all windows NOT_VALID when the popup moves or hides.
- At first always display the popup windows at the end of update_screen(),
  lowest zindex first.
- Later make it more efficient and avoid flicker
- Use a separate list of windows, one for each tab and one global.  Also put
  "aucmd_win" in there.
- add optional {buf} command to execute().  Only works for a buffer that is
  visible in a window in the current tab or in a popup window.
  E.g. for execute('syntax enable', 'silent', bufnr)


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

THIS IS UNDER DESIGN - ANYTHING MAY STILL CHANGE  

Proposal and discussion on issue #4063: https://github.com/vim/vim/issues/4063

[functions to be moved to eval.txt later, keep list 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
                {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')


popup_dialog({text}, {options})                         popup_dialog()
                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()
                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()
                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()
                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_show({id})                                                popup_show()
                If {id} is a hidden popup, show it now.

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.

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".


popup_filter_menu({id}, {key})                          popup_filter_menu()
                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()
                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()
                Override options in popup {id} with entries in {options}.


popup_getoptions({id})                                  popup_getoptions()
                Return the {options} for popup {id}.


popup_close({id})                                       popup_close()
                Close popup {id}.

                                                        :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
TODO: more

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

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".
        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"
        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 somewhere
                        near the cursor.
        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"
        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.
        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
        title           text to be displayed above the first item in the
                        popup, on top of any border
        wrap            TRUE to make the lines wrap (default TRUE)
        highlight       highlight group name to use for the text, defines the
                        background and foreground color
        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
        borderhighlight highlight group name to use for the border
        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
        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
        filter          a callback that can filter typed characters, see 
                        popup-filter
        callback        a callback to be used when the popup closes, e.g. when
                        using popup_filter_menu(), see popup-callback.

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(), but not exactly the
same, since they only apply to one line.
        col             starting column, counted in bytes, use one for the
                        first column.
        length          length of text in bytes; can be zero
        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


POPUP FILTER                                            popup-filter

A callback that gets any typed keys while a popup is displayed.  The filter is
not invoked for as long as 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.

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

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',
                \ })


 vim:tw=78:ts=8:noet:ft=help:norl:

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