[mini.pick]: How to Customize the Top Title and make separate preview window

[krovuxdev]

Contributing guidelines

• I have read CODE_OF_CONDUCT.md

Module(s)

mini.pick

Question

I want to know how to customize the title that appears at the top, both on the left and on the right. I already tried something like title_pos = "center" for Files (rg), but it doesn't work. I want it to look like in this picture."

[echasnovski]

Unfortunately, the answer is that there is no way, mostly because of two reasons:

• Allowing them to be properly configurable would require an extra configuration entry for the part which (deliberately) not exposed to the user, i.e. window title and footer content.
• In general I consider both of those parts useful and hiding them will severely affect usability. And adding an option to hide some/all of them is against this.

So I am afraid this part will remain as is.

[krovuxdev]

Sure! Here's my actual code :D

local M = {}
M.state = {
    preview = {
        buf = -1,
        win = -1,
    },
}
M.test_nvim = function(opts)
    opts = opts or {}
    local height = math.floor(0.3 * vim.o.lines)
    local width = math.floor(0.6 * vim.o.columns)
    local buf = vim.api.nvim_create_buf(false, true)
    local win_cfg = {
        title = "Grep Preview",
        title_pos = "center",
        width = width,
        height = height + 2,
        row = 11,
        col = math.floor((vim.o.columns - width) / 2),
        relative = "editor",
        style = "minimal",
        border = "rounded",
    }
    local win = vim.api.nvim_open_win(buf, false, win_cfg)
    vim.api.nvim_buf_set_option(buf, "bufhidden", "wipe")
    vim.api.nvim_buf_set_lines(buf, 0, -1, false, {

        MiniPick.default_preview(),
        -- MiniPick.config.source.preview(),
    })
    return { buf = buf, win = win }
end
vim.api.nvim_create_autocmd("User", {
    pattern = "MiniPickStart",
    callback = function()
        M.state.preview = M.test_nvim { buf = M.state.preview.buf }
    end,
})
vim.api.nvim_create_autocmd("User", {
    pattern = "MiniPickStop",
    callback = function()
        vim.api.nvim_win_close(M.state.preview.win, true)
    end,
})

[echasnovski]

The problem here is that there is no actual logic about how and when preview should be updated. Plus default_preview(buf, item) should be called directly.

Here is a crude prototype which will try preview item every 10 milliseconds:

local preview_win_id, preview_buf_id, preview_item = nil, nil, nil
local ensure_winbuf = function()
  if not (type(preview_buf_id) == 'number' and vim.api.nvim_buf_is_valid(preview_buf_id)) then
    preview_buf_id = vim.api.nvim_create_buf(false, true)
    vim.bo[preview_buf_id].bufhidden = 'wipe'
  end

  if not (type(preview_win_id) == 'number' and vim.api.nvim_win_is_valid(preview_win_id)) then
    local win_config = {
      relative = 'editor',
      anchor = 'NE',
      width = math.floor(0.3 * vim.o.columns),
      height = math.floor(0.3 * vim.o.lines),
      col = vim.o.columns,
      row = 1,
      style = 'minimal',
      title = 'Preview',
      title_pos = 'center',
      border = 'rounded',
    }
    preview_win_id = vim.api.nvim_open_win(preview_buf_id, false, win_config)
  end
end

local ensure_no_winbuf = function()
  pcall(vim.api.nvim_win_close, preview_win_id, true)
  pcall(vim.api.nvim_buf_delete, preview_win_id, { force = true })
end

local preview_timer = vim.loop.new_timer()

local n = 0
local preview_show = vim.schedule_wrap(function()
  local matches = MiniPick.get_picker_matches()
  if matches == nil then
    preview_timer:stop()
    ensure_no_winbuf()
    return
  end

  if vim.deep_equal(preview_item, matches.current) then return end
  preview_item = matches.current
  -- Workaround special preview in `builtin.help`
  if MiniPick.get_picker_opts().source.name == 'Help' then
    pcall(vim.api.nvim_buf_delete, preview_buf_id, { force = true })
  end
  ensure_winbuf()

  local preview = MiniPick.get_picker_opts().source.preview
  vim.schedule(function() preview(preview_buf_id, preview_item) end)
end)

vim.api.nvim_create_autocmd('User', {
  pattern = 'MiniPickStart',
  callback = function() preview_timer:start(10, 10, preview_show) end,
})

It works on most "normal" pickers (like builtin.files, builtin.grep, etc.), but there are some issues with builtin.grep_live (as it is inherently special). Edit: should now also work on latest main branch.

If making this preview work 100% of the time will be blocked by some 'mini.pick' implementation details, we can talk about updating those but only if there is a working patch which doesn't break existing tests. To be perfectly honest I am not really interested into tracking down source of issues which are only the result of custom "outside" preview.

[krovuxdev]

Wow! It worked, thank you so much! :D Now I can continue with MiniPick. Next, I just need to add something with VimResized or WinResized to scale or hide the preview. I suppose I can manage that.

Thanks for your help! :D

[krovuxdev]

@echasnovski

By the way, I was analyzing each command from MiniExtras for pick.
When using MiniPick with the preview option enabled, the behavior of the search prompt presents the following issue:

• If I type a valid term, such as hello or print, MiniPick works correctly and displays the expected results.
• If I type something that has no matches, such as xxxor xxxxxx, MiniPick closes automatically instead.
• Additionally, if I try to delete the invalid text using backspace, MiniPick also closes automatically, without giving me the opportunity to continue typing.
  

[echasnovski]

• If I type something that has no matches, such as xxxor xxxxxx, MiniPick closes automatically instead.

• Additionally, if I try to delete the invalid text using backspace, MiniPick also closes automatically, without giving me the opportunity to continue typing.

Picker automatically closing is the sign that there was an error. Unfortunately, it is an implementation issue with using vim.fn.getcharstr() that properly showing errors is a problem. Debugging this usually involves logging inside custom actions that might provide trouble.

In this particular case, there should be some guard against nil previewed item (which is the case when there are no matches).