Paste link to image in clipboard when editing Markdown

Question

I have an image on the clipboard and I want to paste it into my document as the text [](img/image1.png).

Instead of first copying it to that directory, I want to do it with a single p key press in Vim. So it hooks p, checks if I am editing a Markdown file, saves the image from the clipboard to the location img/image1.png, and inserts [](img/image1.png) into the file.

Is this possible with Vim?

I use macOS and terminal Vim.

Answer 1

The usual terminal command for accessing the clipboard on Mac is pbpaste. However, this doesn't work for image data, so we have to resort to AppleScript:

nnoremap <silent> <buffer> p :call MarkdownClipboardImage()<cr>

function! MarkdownClipboardImage() abort
  " Create `img` directory if it doesn't exist
  let img_dir = getcwd() . '/img'
  if !isdirectory(img_dir)
    silent call mkdir(img_dir)
  endif

  " First find out what filename to use
  let index = 1
  let file_path = img_dir . "/image" . index . ".png"
  while filereadable(file_path)
    let index = index + 1
    let file_path = img_dir . "/image" . index . ".png"
  endwhile

  let clip_command = 'osascript'
  let clip_command .= ' -e "set png_data to the clipboard as «class PNGf»"'
  let clip_command .= ' -e "set referenceNumber to open for access POSIX path of'
  let clip_command .= ' (POSIX file \"' . file_path . '\") with write permission"'
  let clip_command .= ' -e "write png_data to referenceNumber"'

  silent call system(clip_command)
  if v:shell_error == 1
    normal! p
  else
    execute "normal! i[](" . file_path . ")"
  endif
endfunction

Add the code above to ~/.vim/after/ftplugin/markdown.vim.

This saves the clipboard data to the file "img/image1.png" if it contains PNG data. It then just uses the :normal! to insert the desired markdown link.

If the clipboard doesn't contain PNG data (or if we're not in a Markdown file), it performs a regular p command.

If I were using this, I'd tidy it up to support further image types and to leave the cursor in a more helpful position, but this works well as a proof of concept.

(I'd also use a <leader>p mapping as suggested by Karl Yngve Lervåg — this seems like functionality I'd prefer to invoke specifically — but that's not what you asked for).

Further reading

• :help :map-<buffer>
• :help system()
• :help v:shell_error
• :help :normal
• AppleScript documentation

Answer 2

The following solution should work on most Linux systems. It requires a relatively updated xclip tool. For a solution that works on MacOS/OSX, see @Rich's answer.

---

I've proposed a solution that maps <leader>p instead of remapping p, since I think this is a much saner approach. The function SaveFile will inspect the clipboard with xclip. If there is an image file, it will be saved to img/imageN.<ext>, unless the file already exists. It will also populate the * register with the [](img/...) text and then paste it.

nnoremap <silent> <leader>p :call SaveFile()<cr>

function! SaveFile() abort
  let targets = filter(
        \ systemlist('xclip -selection clipboard -t TARGETS -o'),
        \ 'v:val =~# ''image''')
  if empty(targets) | return | endif

  let outdir = expand('%:p:h') . '/img'
  if !isdirectory(outdir)
    call mkdir(outdir)
  endif

  let mimetype = targets[0]
  let extension = split(mimetype, '/')[-1]
  let tmpfile = outdir . '/savefile_tmp.' . extension
  call system(printf('xclip -selection clipboard -t %s -o > %s',
        \ mimetype, tmpfile))

  let cnt = 0
  let filename = outdir . '/image' . cnt . '.' . extension
  while filereadable(filename)
    call system('diff ' . tmpfile . ' ' . filename)
    if !v:shell_error
      call delete(tmpfile)
      break
    endif

    let cnt += 1
    let filename = outdir . '/image' . cnt . '.' . extension
  endwhile

  if filereadable(tmpfile)
    call rename(tmpfile, filename)
  endif

  let @* = '[](' . fnamemodify(filename, ':.') . ')'
  normal! "*p
endfunction

Answer 3

Based on answers above I've created a Plugin for vim solving my problem for macos and possibly for linux. Hope you'll find this plugin useful. I also appreciate any contributions and feature requests.