OSC 9;4 support (progress report)

[sanpii]

[Edit: this description has been taken over by the maintainers to track the status]

https://conemu.github.io/en/AnsiEscapeCodes.html#ConEmu_specific_OSC

ESC ] 9 ; 4 ; st ; pr ST
Set progress state on Windows 7 taskbar and ConEmu title. When st is 0: remove progress. When st is 1: set progress value to pr (number, 0-100). When st is 2: set error state in progress on Windows 7 taskbar, pr is optional. When st is 3: set indeterminate state. When st is 4: set paused state, pr is optional.

It's being integrated into cargo: rust-lang/cargo#14615

Status of implementation within wezterm:

It basically works, and you can use the config fragment shown below to customize how it appears

• Escape sequences are processed and exposed via lua
• Multiplexer client synchronizes progress during (re)connect
• Show progress by default
  • Decide on how that appears in tab titles
  • Decide on how that appears in window titles
• Decide how to deal with indeterminate progress state.
  • Should we try to do something fancy for auto-animating a spinner of some kind?
• Windows: update the taskbar icon/state. (unsure if we'll bother with this)
  • Needs some design: what to do when multiple panes/tabs have progress to display? Show the active one only?
  • Needs API support in the Window crate.

local wezterm = require 'wezterm'

local function tab_title(tab_info)
  local title = tab_info.tab_title
  -- if the tab title is explicitly set, take that
  if title and #title > 0 then
    return title
  end
  -- Otherwise, use the title from the active pane
  -- in that tab
  return tab_info.active_pane.title
end

local PCT_GLYPHS = {
  wezterm.nerdfonts.md_circle_slice_1,
  wezterm.nerdfonts.md_circle_slice_2,
  wezterm.nerdfonts.md_circle_slice_3,
  wezterm.nerdfonts.md_circle_slice_4,
  wezterm.nerdfonts.md_circle_slice_5,
  wezterm.nerdfonts.md_circle_slice_6,
  wezterm.nerdfonts.md_circle_slice_7,
  wezterm.nerdfonts.md_circle_slice_8,
}
local function pct_glyph(pct)
  local slot = math.floor(pct / 12)
  return PCT_GLYPHS[slot+1]
end

wezterm.on(
  'format-tab-title',
  function(tab, tabs, panes, config, hover, max_width)
    local progress = tab.active_pane.progress or "None"
    local title = tab_title(tab)
    local elements = {
      { Text = string.format("%d: ", tab.tab_index+1) },
    }

    if progress ~= "None" then
      local color = 'green'
      local status
      if progress.Percentage ~= nil then
        -- status = string.format("%d%%", progress.Percentage)
        status = pct_glyph(progress.Percentage)
      elseif progress.Error ~= nil then
        -- status = string.format("%d%%", progress.Error)
        status = pct_glyph(progress.Error)
        color = 'red'
      elseif progress == "Indeterminate" then
        status = "~"
      else
        status = wezterm.serde.json_encode(progress)
      end

      table.insert(elements, { Foreground = { Color = color } })
      table.insert(elements, { Text = status })
      table.insert(elements, { Foreground = 'Default' })
    end

    table.insert(elements, { Text = ' ' .. title .. ' ' })

    return elements
  end
)

return wezterm.config_builder()

[wez]

I just pushed a first pass at supporting these. There's no automatic rendering of the state in the UI, but you can customize exactly how it will manifest in lua. Here's a basic example:

Edit: example moved to the issue description

[wez]

with the updated example above, the progress renders like this in the tab title, with that green circle filling in as the progress advances: