Add popup preview border

CHANGELOG.md

@@ -3,6 +3,10 @@ CHANGELOG
 
 ## [unreleased]
 
+### Added
+
+- Add `g:clap_popup_border` for adding the border for the preview popup. ([#349](https://github.com/liuchengxu/vim-clap/pull/349))
+
 ### Improved
 
 - Print a note about Rust nightly is requred for building the Python dynamic module.

autoload/clap.vim

@@ -88,6 +88,8 @@ let g:clap_enable_icon = get(g:, 'clap_enable_icon', exists('g:loaded_webdevicon
 let g:clap_insert_mode_only = get(g:, 'clap_insert_mode_only', v:false)
 let g:clap_providers_relaunch_code = get(g:, 'clap_providers_relaunch_code', '@@')
 
+let g:clap_popup_border = get(g:, 'clap_popup_border', 'rounded')
+
 function! s:inject_default_impl_is_ok(provider_info) abort
   let provider_info = a:provider_info
 

autoload/clap/popup.vim

@@ -102,16 +102,29 @@ function! s:create_preview() abort
   if !exists('s:preview_winid') || empty(popup_getpos(s:preview_winid))
     let pos = popup_getpos(s:display_winid)
     let line = pos.line + pos.height
-    let s:preview_winid = popup_create([], {
-          \ 'wrap': v:false,
+    let preview_opts = {
+          \ 'wrap': v:true,
           \ 'zindex': 100,
           \ 'scrollbar': 0,
           \ 'highlight': 'ClapPreview',
           \ 'col': pos.col,
           \ 'line': line,
           \ 'minwidth': pos.width,
           \ 'maxwidth': pos.width,
-          \ })
+          \ }
+    if g:clap_popup_border !=? 'nil'
+      let borderchars = ['─', '│', '─', '│']
+      if g:clap_popup_border ==? 'rounded'
+        let borderchars += ['╭', '╮', '╯', '╰']
+      else
+        let borderchars += ['┌', '┐', '┘', '└']
+      endif
+      let preview_opts.border = []
+      let preview_opts.borderchars = borderchars
+      let preview_opts.minwidth -= 2
+      let preview_opts.maxwidth -= 2
+    endif
+    let s:preview_winid = popup_create([], preview_opts)
     call popup_hide(s:preview_winid)
     call win_execute(s:preview_winid, 'setlocal nonumber')
     let g:clap#popup#preview.winid = s:preview_winid

doc/clap.txt

@@ -148,6 +148,20 @@ g:clap_popup_input_delay                              *g:clap_popup_input_delay*
   This option is only meaningful for Vim, NeoVim does not have this delay.
 
 
+g:clap_popup_border                                        *g:clap_popup_border*
+
+  Type: |String|
+  Default: `'rounded'`
+
+  This variable adds the border to the preview popup, avaliable border style:
+  `'rounded'`, `'sharp'`.
+
+  Set it to `'nil'` to disable the border.
+
+  NeoVim's floating_win is unsupported as it does not have a native
+  border option and the workaround is not good for clap's use case.
+
+
 g:clap_maple_delay                                          *g:clap_maple_delay*
 
   Type: |Number|