preview information shown in hover at the cursor

Author: jerdna-regeiz

autoload/lsp/ui/vim/output.vim

@@ -1,10 +1,83 @@
+let s:supports_floating = exists('*nvim_open_win')
+let s:win = v:false
+
+function! lsp#ui#vim#output#closepreview() abort
+  if win_getid() == s:win
+    " Don't close if window got focus
+    return
+  endif
+  pclose
+  let s:win = v:false
+  autocmd! lsp_float_preview_close CursorMoved,CursorMovedI,VimResized *
+endfunction
+
+function! s:get_float_positioning(height, width)
+    let l:height = a:height
+    let l:width = a:width
+    " For a start show it below/above the cursor
+    " TODO: add option to configure it 'docked' at the bottom/top/right
+    let l:y = winline()
+    if l:y + l:height >= &lines
+      " Float does not fit
+      if l:y - 2 > l:height
+        " Fits above
+        let l:y = winline() - l:height
+      elseif l:y - 2 > &lines - l:y
+        " Take space above cursor
+        let l:y = 1
+        let l:height = winline()-2
+      else
+        " Take space below cursor
+        let l:height = &lines -l:y
+      endif
+    endif
+    let l:col = col(".")
+    " Positioning is not window but screen relative
+    let l:opts = {
+          \ 'relative': 'win',
+          \ 'row': l:y,
+          \ 'col': l:col,
+          \ 'width': l:width,
+          \ 'height': l:height,
+          \ }
+    return l:opts
+endfunction
+
+function! lsp#ui#vim#output#floatingpreview(data) abort
+    let l:buf = nvim_create_buf(v:false, v:true)
+    call setbufvar(l:buf, '&signcolumn', 'no')
+
+    " Try to get as much pace right-bolow the cursor, but at least 10x10
+    let l:width = max([float2nr(&columns - col(".") - 10), 10])
+    let l:height = max([&lines - winline() + 1, 10])
+
+    let l:opts = s:get_float_positioning(l:height, l:width)
+
+    let s:win = nvim_open_win(buf, v:true, l:opts)
+    call nvim_win_set_option(s:win, 'winhl', "Normal:Pmenu,NormalNC:Pmenu")
+    call nvim_win_set_option(s:win, 'foldenable', v:false)
+    call nvim_win_set_option(s:win, 'wrap', v:true)
+    call nvim_win_set_option(s:win, 'statusline', '')
+    call nvim_win_set_option(s:win, 'number', v:false)
+    call nvim_win_set_option(s:win, 'relativenumber', v:false)
+    call nvim_win_set_option(s:win, 'cursorline', v:false)
+    " Enable closing the preview with esc, but map only in the scratch buffer
+    nmap <buffer><silent> <esc> :pclose<cr>
+    return s:win
+endfunction
+
 function! lsp#ui#vim#output#preview(data) abort
     " Close any previously opened preview window
     pclose
 
     let l:current_window_id = win_getid()
 
-    execute &previewheight.'new'
+    if s:supports_floating && g:lsp_preview_float
+      call lsp#ui#vim#output#floatingpreview(a:data)
+    else
+      execute &previewheight.'new'
+    endif
+    let s:win = win_getid()
 
     let l:ft = s:append(a:data)
     " Delete first empty line
@@ -13,6 +86,9 @@ function! lsp#ui#vim#output#preview(data) abort
     setlocal readonly nomodifiable
 
     let &l:filetype = l:ft . '.lsp-hover'
+    " Get size information while still having the buffer active
+    let l:bufferlines = line("$")
+    let l:maxwidth = max(map(getline(1, '$'), 'strdisplaywidth(v:val)'))
 
     if g:lsp_preview_keep_focus
       " restore focus to the previous window
@@ -21,6 +97,17 @@ function! lsp#ui#vim#output#preview(data) abort
 
     echo ''
 
+    if s:supports_floating && s:win && g:lsp_preview_float
+      let l:win_config = {}
+      let l:height = min([winheight(s:win), l:bufferlines])
+      let l:width = min([winwidth(s:win), l:maxwidth])
+      let l:win_config = s:get_float_positioning(l:height, l:width)
+      call nvim_win_set_config(s:win, l:win_config )
+      augroup lsp_float_preview_close
+        autocmd! lsp_float_preview_close CursorMoved,CursorMovedI,VimResized *
+        autocmd CursorMoved,CursorMovedI,VimResized * call lsp#ui#vim#output#closepreview()
+      augroup END
+    endif
     return ''
 endfunction
 

doc/vim-lsp.txt

@@ -13,6 +13,7 @@ CONTENTS                                                  *vim-lsp-contents*
       g:lsp_diagnostics_enabled             |g:lsp_diagnostics_enabled|
       g:lsp_auto_enable                     |g:lsp_auto_enable|
       g:lsp_preview_keep_focus              |g:lsp_preview_keep_focus|
+      g:lsp_preview_float		    |g:lsp_preview_float|
       g:lsp_insert_text_enabled             |g:lsp_insert_text_enabled|
       g:lsp_text_edit_enabled               |g:lsp_text_edit_enabled|
       g:lsp_diagnostics_echo_cursor         |g:lsp_diagnostics_echo_cursor|
@@ -149,6 +150,23 @@ g:lsp_preview_keep_focus                         *g:lsp_preview_keep_focus*
 
     * |preview-window| can be closed using the default vim mapping - `<c-w><c-z>`.
 
+g:lsp_preview_float                         *g:lsp_preview_float*
+    Type: |Number|
+    Default: `1`
+
+    If set and nvim_win_open() is available, hover information are shown in a
+    floating window as |preview-window| at the cursor position.
+    The |preview-window| is closed automatically on cursor moves, unless it is
+    focused. While focused it may be closed with <esc>.
+    This feature requires neovim 0.4.0 (current master).
+
+    Example:
+	" Opens preview windows as floating
+	let g:lsp_preview_float = 1
+
+	" Opens preview windows as normal windows
+	let g:lsp_preview_float = 0
+
 g:lsp_insert_text_enabled                       *g:lsp_insert_text_enabled*
     Type: |Number|
     Default: `1`
@@ -535,6 +553,9 @@ Gets the hover information and displays it in the |preview-window|.
  * |preview-window| can be closed using the default vim mapping - `<c-w><c-z>`.
  * To control the default focus of |preview-window| for |LspHover|
    configure |g:lsp_preview_keep_focus|.
+ * If using neovim with nvim_win_open() available, |g:lsp_preview_float| can be
+   set to enable a floating preview at the cursor which is closed automatically
+   on cursormove if not focused and can be closed with <esc> if focused.
 
 
 LspNextError						     *LspNextError*

plugin/lsp.vim

@@ -25,6 +25,7 @@ let g:lsp_use_event_queue = get(g:, 'lsp_use_event_queue', has('nvim') || has('p
 let g:lsp_insert_text_enabled= get(g:, 'lsp_insert_text_enabled', 1)
 let g:lsp_text_edit_enabled = get(g:, 'lsp_text_edit_enabled', has('patch-8.0.1493'))
 let g:lsp_highlight_references_enabled = get(g:, 'lsp_highlight_references_enabled', 1)
+let g:lsp_preview_float = get(g:, 'lsp_preview_float', 1)
 
 if g:lsp_auto_enable
     augroup lsp_auto_enable