How to paste screenshot in vim buffer on Ubuntu

Goal

In markdown files, you can insert an image by writing ![alt text](/path/to/image), but doing this task manually is quite cumbersome. Let me state the manual steps first to make you understand why this is cumbersome.
1. Take screenshot
2. Save it at proper location
3. Mention the image in the markdown using the above mentioned syntax, i.e ![]()

Now, I wanted to complete the all the above steps in least number of keystrokes, in one step! Let me explain how I did it, then I’ll also explain what challenges I faced in the meanwhile. All the steps were performed on Ubuntu 20, hence it might differ from OS to OS. Also, this was a great learning experience for me, hence want to document it the best way possible.

Procedure

I thought of trying out this vim plugin but it was surprisingly not working. Then I read the documentation properly which led me to the genesis of this plugin which is this stack exchange answer. Then I started following this answer, understood the vimscript then added it to my vimrc but, it was still not working :(

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

Upon investigating it further I readlized that it was missing ! infront of []() while inserting the image in the script, but, even after updating the vimscript it was still not working!
Then I tried to figure out if my vim system register was working properly. It turns out my vim version does not support clipboard! (You can check this by running vim --version | grep clipboard, then see it is -clipboard or +clipboard). Hence I had to install vim-gtk to enable this feature. I’ve raised an issue in the project to specify this issue. Now I was able to paste the data stored in system clipboard to vim buffer and vice-versa.
But it turns out I was still not able to copy screenshot using the default tool, but able to paste in vim buffer yet. Now I need to solve the copy problem!
Ubuntu has gnome-screenshot which allows you to capture portion of the screen (IMHO most flexible way to take screenshot) and then paste it anywhere I want. But, after lots of frustration I understood that gnome-screenshot is taking the screenshot but it is not being copied to xclip clipboard manager which is what I am using to paste the screenshot in vim buffer. I order to get around this I had to assign a keyboard shortcut to the following command to take screenshot and place it in xclip

gnome-screenshot -acf /tmp/test && cat /tmp/test | xclip -i -selection clipboard -target image/png

Ultimately now it worked! Now I can take screenshot using the custom keyboard shortcut (which pops up a terminal too) and then paste it using <leader>p in vim since I have mapped it this way in my vimrc.

Conclusion

It was complicated and took me a lot of time to figure it out but it offered me chance to learn many things. If you know how to do it better please let me know, or, if you find similar issue, tweet to me or DM me on LinkedIn, I would be happy to help!