feat: add initial implementation for kitty unicode placeholders and d…

…ebugging

lua/image/backends/kitty/helpers.lua

@@ -2,6 +2,7 @@ local utils = require("image/utils")
 local codes = require("image/backends/kitty/codes")
 
 local stdout = vim.loop.new_tty(1, false)
+local is_tmux = vim.env.TMUX ~= nil
 
 -- https://github.com/edluffy/hologram.nvim/blob/main/lua/hologram/terminal.lua#L77
 local get_chunked = function(str)
@@ -13,10 +14,6 @@ local get_chunked = function(str)
   return chunks
 end
 
-local write = vim.schedule_wrap(function(data)
-  stdout:write(data)
-end)
-
 -- https://github.com/edluffy/hologram.nvim/blob/main/lua/hologram/state.lua#L15
 local get_term_size = function()
   local ffi = require("ffi")
@@ -52,6 +49,27 @@ local get_term_size = function()
   }
 end
 
+local encode = function(data)
+  if is_tmux then return "\x1bPtmux;" .. data:gsub("\x1b", "\x1b\x1b") .. "\x1b\\" end
+  return data
+end
+
+local write = vim.schedule_wrap(function(data)
+  if data == "" then return end
+  utils.debug("write:", vim.inspect(data))
+  stdout:write(data)
+  -- vim.fn.chansend(vim.v.stderr, data)
+end)
+
+local move_cursor = function(x, y, save)
+  if save then write("\x1b[s") end
+  write(("\x1b[" .. y .. ";" .. x .. "H"))
+end
+
+local restore_cursor = function()
+  write("\x1b[u")
+end
+
 ---@param config KittyControlConfig
 ---@param data? string
 -- https://github.com/edluffy/hologram.nvim/blob/main/lua/hologram/terminal.lua#L52
@@ -65,31 +83,39 @@ local write_graphics = function(config, data)
     end
   end
   control_payload = control_payload:sub(0, -2)
-  log(control_payload)
 
   if data then
     if config.transmit_medium ~= codes.control.transmit_medium.direct then data = utils.base64.encode(data) end
     local chunks = get_chunked(data)
     for i = 1, #chunks do
-      write("\x1b_G" .. control_payload .. ";" .. chunks[i] .. "\x1b\\")
+      write(encode("\x1b_G" .. control_payload .. ";" .. chunks[i] .. "\x1b\\"))
       if i == #chunks - 1 then
         control_payload = "m=0"
       else
         control_payload = "m=1"
       end
     end
   else
-    write("\x1b_G" .. control_payload .. "\x1b\\")
+    utils.debug("control:", control_payload)
+    write(encode("\x1b_G" .. control_payload .. "\x1b\\"))
   end
 end
 
-local move_cursor = function(x, y)
-  write("\x1b[s")
-  write("\x1b[" .. y .. ":" .. x .. "H")
-end
+-- local rshift = function(x, by)
+--   return math.floor(x / 2 ^ by)
+-- end
+local write_placeholder = function(image_id, x, y, rows, columns)
+  local foreground = "\x1b[38;5;" .. image_id .. "m"
+  local restore = "\x1b[39m"
 
-local restore_cursor = function()
-  write("\x1b[u")
+  write(foreground)
+  for i = 0, rows - 1 do
+    move_cursor(x, y + i + 1)
+    for j = 0, columns - 1 do
+      write(codes.placeholder .. codes.diacritics[i + 1] .. codes.diacritics[j + 1])
+    end
+  end
+  write(restore)
 end
 
 return {
@@ -98,4 +124,5 @@ return {
   restore_cursor = restore_cursor,
   write = write,
   write_graphics = write_graphics,
+  write_placeholder = write_placeholder,
 }

lua/image/backends/kitty/init.lua

@@ -4,18 +4,34 @@ local helpers = require("image/backends/kitty/helpers")
 
 local term_size = helpers.get_term_size()
 
+local images = {}
+local last_kitty_id = 0
+
+local is_tmux = vim.env.TMUX ~= nil
+local tmux_has_passthrough = false
+
+if is_tmux then
+  local ok, result = pcall(vim.fn.system, "tmux show -Apv allow-passthrough")
+  if ok and result == "on\n" then tmux_has_passthrough = true end
+end
+
 ---@type Backend
 local backend = {}
 
-backend.setup = function()
+-- TODO: check for kitty
+backend.setup = function(options)
+  backend.options = options
+
+  if is_tmux and not tmux_has_passthrough then
+    utils.throw("tmux does not have allow-passthrough enabled")
+    return
+  end
+
   vim.defer_fn(function()
     -- log(get_term_size())
   end, 1000)
 end
 
-local images = {}
-local last_kitty_id = 0
-
 -- extend from empty line strategy to use extmarks
 backend.render = function(image_id, url, x, y, max_cols, max_rows)
   if not images[image_id] then
@@ -24,25 +40,59 @@ backend.render = function(image_id, url, x, y, max_cols, max_rows)
   end
   local kitty_id = images[image_id]
 
+  local image_width, image_height = utils.png.get_dimensions(url)
+  local rows = math.floor(image_height / term_size.cell_height)
+  local columns = math.floor(image_width / term_size.cell_width)
+  -- local rows = max_rows
+  -- local pixel_height = math.floor(max_rows * term_size.cell_height)
+  -- local pixel_width = math.floor(image_width * pixel_height / image_height)
+  -- local columns = math.floor(pixel_width / term_size.cell_width)
+  -- log({
+  --   image_width = image_width,
+  --   image_height = image_height,
+  --   columns = columns,
+  --   rows = rows,
+  -- })
+
+  -- if true then
+  --   helpers.move_cursor(10, 10)
+  --   return
+  -- end
+
+  helpers.move_cursor(x, y, true)
+
+  -- transmit image
   helpers.write_graphics({
     action = codes.control.action.transmit,
+    image_id = kitty_id,
     transmit_format = codes.control.transmit_format.png,
     transmit_medium = codes.control.transmit_medium.file,
+    display_cursor_policy = codes.control.display_cursor_policy.do_not_move,
+    display_virtual_placeholder = is_tmux and 1 or 0,
     quiet = 2,
-    image_id = kitty_id,
-    placement_id = 1,
   }, url)
 
-  helpers.move_cursor(x + 1, y + 1)
-
-  local rows = max_rows
-  local image_width, image_height = utils.png.get_dimensions(url)
-  local pixel_height = math.floor(max_rows * term_size.cell_height)
-  local pixel_width = math.floor(image_width * pixel_height / image_height)
-  local columns = math.floor(pixel_width / term_size.cell_width)
+  -- unicode placeholders
+  if is_tmux then
+    -- create virtual image placement
+    helpers.write_graphics({
+      action = codes.control.action.display,
+      quiet = 2,
+      image_id = kitty_id,
+      display_rows = rows,
+      display_columns = columns,
+      display_cursor_policy = codes.control.display_cursor_policy.do_not_move,
+      display_virtual_placeholder = 1,
+    })
 
-  log({ image_width, image_height, rows, columns })
+    -- write placeholder
+    helpers.write_placeholder(kitty_id, x, y, rows, columns)
+    helpers.restore_cursor()
+    return
+  end
 
+  -- default display
+  helpers.move_cursor(x + 1, y + 1)
   helpers.write_graphics({
     action = codes.control.action.display,
     quiet = 2,
@@ -53,7 +103,6 @@ backend.render = function(image_id, url, x, y, max_cols, max_rows)
     display_zindex = -1,
     display_cursor_policy = codes.control.display_cursor_policy.do_not_move,
   })
-
   helpers.restore_cursor()
 end
 

lua/image/integrations/markdown.lua

@@ -101,7 +101,7 @@ end
 
 ---@type fun(ctx: IntegrationContext)
 local setup = function(ctx)
-  -- local options = ctx.options --[[@as MarkdownIntegrationOptions]]
+  local options = ctx.options --[[@as MarkdownIntegrationOptions]]
   setup_autocommands(ctx)
   render(ctx)
 end

lua/image/utils/init.lua

@@ -19,9 +19,17 @@ local throw = logger.create_logger({
   output_file = "/tmp/nvim-image.txt",
 })
 
+local debug = logger.create_logger({
+  prefix = "[image.nvim]",
+  formatter = logger.default_log_formatter,
+  handler = nil,
+  output_file = "/tmp/nvim-image.txt",
+})
+
 return {
   log = log,
   throw = throw,
+  debug = debug,
   base64 = base64,
   png = png,
   random = random,