Smear when jumping to command

[sphamba]

No description provided.

[bew]

Is there a limitation for this to overcome? or is it just not implemented yet?

[sphamba]

In my understanding, Neovim blocks the execution of some API calls when entering the command prompt, such as updating the window and buffer options (which smear-cursor relies heavily on). So I am not sure that it would be technically possible. The (unsatisfactory) alternative would be to hide the smear instead of letting it frozen, see #15 ☹️

[ColinKennedy]

It doesn't look like Neovim allows people to draw virtual text (I assume that's what smear-cursor.nvim is using) during command mode.

A quick test

See test

-- List of random virtual text options
local random_texts = {
  "Hello, Neovim!",
  "Lua rocks!",
  "Virtual text demo",
}

-- Function to get a random number within a range
local function random_range(min, max)
  return math.random(min, max)
end

-- Function to display virtual text at a random position with random text
local function show_random_virtual_text()
  -- Get the current buffer
  local buf = vim.api.nvim_get_current_buf()

  -- Get random line and column within the buffer
  local num_lines = vim.api.nvim_buf_line_count(buf)
  local line = random_range(0, num_lines - 1)
  local col = random_range(0, 80)  -- You can adjust the column limit based on your terminal width

  -- Pick a random text from the list
  local text = random_texts[math.random(#random_texts)]

  -- Set the virtual text at the random position
  vim.api.nvim_buf_set_virtual_text(buf, 0, line, {{text, "Search"}}, {})
end

-- Create a timer to run the function every second (1000 ms)
local timer = vim.uv.new_timer()

-- Start the timer to call show_random_virtual_text every 1000ms
timer:start(0, 1000, vim.schedule_wrap(function()
  show_random_virtual_text()
end))

Run the file, then enter command mode. It should draw a virtual text every second but doesn't. Instead, the accumulated time is executed once command mode is exited. e.g. If you wait 5 seconds, you get ~5 messages when you exit.

I found that if you type a bunch of text in the command mode section it will update without leaving command mode. Sometimes. All of the same behavior applies to noice.nvim. noice uses vim.ui_attach(...) so I don't think anything can be done there.

[ColinKennedy]

If you go the "just hide it" route, I'd imagine you'd want to use ModeChanged. (Edit: Actually thinking about it if virtual text changes are not allowed then ModeChanged would probably be too late)

Other than rendering the smear what other things would smear-cursor.nvim need specifically to interact with Neovim?

I did a quick test and you can set buffer variables while in command mode.

See here

-- List of random virtual text options
local random_texts = {
  "Hello, Neovim!",
  "Lua rocks!",
  "Virtual text demo",
}

-- Function to get a random number within a range
local function random_range(min, max)
  return math.random(min, max)
end

-- Function to display virtual text at a random position with random text
local function show_random_virtual_text()
  -- Get the current buffer
  local buf = vim.api.nvim_get_current_buf()

  -- Get random line and column within the buffer
  local num_lines = vim.api.nvim_buf_line_count(buf)
  local line = random_range(0, num_lines - 1)
  local col = random_range(0, 80)  -- You can adjust the column limit based on your terminal width

  -- Pick a random text from the list
  local text = random_texts[math.random(#random_texts)]

  -- Set the virtual text at the random position
  vim.api.nvim_buf_set_virtual_text(buf, 0, line, {{text, "Search"}}, {})
end

-- Create a timer to run the function every second (1000 ms)
local timer = vim.uv.new_timer()

local buffer = vim.api.nvim_get_current_buf()

-- Start the timer to call show_random_virtual_text every 1000ms
timer:start(0, 1000, vim.schedule_wrap(function()
  show_random_virtual_text()

  if vim.b.test then
    local file = io.open("/tmp/foo", "a+")
    file:write(vim.b.test .. "\n")
    file:close()
  end

  local text = random_texts[math.random(#random_texts)]

  vim.b.test = text
end))

[sphamba]

To render the smear, there are:

• floating windows
• scratch buffers
• one extmark per buffer, with a given highlight group

So to make the smear disappear, I imagine we could:

• hide/move/destroy windows or buffers
• delete extmarks
• change the highlight groups to something invisible

I started doing some testing with timer and without schedule_wrap, that allows to run code even after a CmdLineEnter event. But we are limited to "fast API" calls, whatever that means

[ColinKennedy]

Update - You can actually force a redraw in command mode!

Details

-- List of random virtual text options
local random_texts = {
  "Hello, Neovim!",
  "Lua rocks!",
  "Virtual text demo",
}

-- Function to get a random number within a range
local function random_range(min, max)
  return math.random(min, max)
end

-- Function to display virtual text at a random position with random text
local function show_random_virtual_text()
  -- Get the current buffer
  local buf = vim.api.nvim_get_current_buf()

  -- Get random line and column within the buffer
  local num_lines = vim.api.nvim_buf_line_count(buf)
  local line = random_range(0, num_lines - 1)
  local col = random_range(0, 80)  -- You can adjust the column limit based on your terminal width

  -- Pick a random text from the list
  local text = random_texts[math.random(#random_texts)]

  -- Set the virtual text at the random position
  vim.api.nvim_buf_set_virtual_text(buf, 0, line, {{text, "Search"}}, {})
end

-- Create a timer to run the function every second (1000 ms)
local timer = vim.uv.new_timer()

-- Start the timer to call show_random_virtual_text every 1000ms
timer:start(0, 1000, vim.schedule_wrap(function()
  vim.cmd.redraw()
  show_random_virtual_text()
end))

Thank you to @echasnovski who pointed it out.

I'm not sure if that unblocks you but more options can't hurt, right?

[sphamba]

@ColinKennedy Thank you for the pointers! Apparently, using timer:start(timeout, 0, ... (equvalent to current implementation) is blocking, while using timer:start(0, interval, ...) is not. I implemented that in #71, and it works 🎉

There is still an issue with keybindings that use the command line (: ... <cr>), which also trigger a smear that I would not expect in this case.

[ColinKennedy]

In general the : ... <cr> case shouldn't come up that much. Most people should be using <cmd> ... <cr> anyway because it's more efficient. I only use :Foo in keybindings when the binding does not end in <cr>. Because in that case I'd be intentionally switching to command mode and would expect smear-cursor to activate.

[craftgear]

Hi, can we disable this feature on configuration?

[sphamba]

Hi, can we disable this feature on configuration?

@craftgear Just added the configuration parameter smear_to_cmd (true by default) #77

[craftgear]

@sphamba Wow, I didn't expect this! Thank you so much😊