I'm the developer of Org mode package "org-link-beautify"
https://repo.or.cz/org-link-beautify.git . The package main theory
is to use org-link-parameters `:activate-func` to do link file preview
with generating thumbnail images or file content etc.

But I found it's slow one some big Org file and slow on small Org file
when previewing has a lot.

I locate and studied the source code of the `:activate-func`.

- [X] locate the core function source code
  + [X] org-link-set-parameters
    - [X] org-link-parameters
      + [X] :activate-func
  + [X] org-mode major mode definition
    + [X] org-set-font-lock-defaults - Set font lock defaults for the current buffer.
      - [X] variable: org-font-lock-extra-keywords - dynamically scoped
        + [X] org-activate-links
          - [X] org-activate-links--text-properties
            + [X] :activate-func
          - [X] org-activate-links--overlays
            + [X] :activate-func

I can see the `org-mode` invoked `org-set-font-lock-defaults` soon when
`org-mode` enabled. I hope the link `:activate-func` function can be
called only on link elements which is VISIBLE (means unfolded subtrees
or similar). So org-mode don't need to render all buffer links at
beginning soon. Instead render them as needed as unfolded. (Maybe I read
source code without fully understand the code. If so, correct me,
thanks.)

So, I hope Org mode maintainer can improve this mechanism. Thanks a lot.

Hope this can improve other Org mode extensions performance too.

-- 

[ stardiviner ]
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