Hi Nicolas,

I tried out the patch, and my comments are in the MWE below.

On Mon, Jul 10, 2017 at 9:59 AM Brett Viren <bv@bnl.gov> wrote:

> Is this saying "subtract the value of 'html_link_root' from the Org link
> to make its URL"?
>
> If so, I think this would not be general enough to help some cases.  For
> example, with Nikola+orgmode and with Nikola's "pretty URLs" option the
> relative location between either the Org source or its generated HTML
> and an image that they both link will differ.
>

Good point. I overlooked that.

I have this MWE that explains the "would like to have" vs "what this patch
gives us":

=====
#+TITLE: ox-html root dir
#+OPTIONS: toc:nil
#+STARTUP: inlineimages
#+HTML_LINK_ROOT: /tmp/site/static/

An =image.png= exists as =/tmp/site/static/images/image.png=.

* This is how the image links should have worked with the link root already
specified
[[/images/image.png]]
- The =HTML_LINK_ROOT= should to appended to the front of the above link if
that
  concatenated path is a valid one.
- Would also like =C-x C-o=, inline image display, etc. to work.
- So a thought.. should the link root specification be made exporter
agnostic?
* This works after adding support for =HTML_LINK_ROOT= ..
.. but
- The link path becomes too long.
- Need to hard-code the full path to the site/blog root directory before
each of
  such links.
[[file:/tmp/site/static/images/image.png]]
=====



> Some details:
>
> Nikola source wants this layout:
>
>   /path/to/my/nikola/posts/my-blog-post.org
>   /path/to/my/nikola/images/unicorn.jpg
>
> The Org source generates to HTML which will be found at this URL path:
>
>   /mysiteroot/posts/my-blog-post/index.html
>

The organization for Hugo posts is something similar. So hopefully we can
have a solution that works for such blogging platforms in general.

In comparsion, the hugo paths would be:

  /path/to/my/hugo/content/posts/my-blog-post.org
  /path/to/my/hugo/static/images/unicorn.jpg

So, right now, either the Org link to the image must be written to be
> invalid (for Org):
>
>   [[../../images/unicorn.jpg]]
>

 Yeah, this is a problem and can probably be fixed if a support for
something like "#+LINK_ROOT" can be made in Org and not specific to an
exporter backend.

Or, some mechanism needs to turn the valid Org link:
>
>   [[../images/unicorn.jpg]]
>
> into either:
>
>   <img src="/mysiteroot/images/unicorn.jpg" ...>
>
> or:
>
>   <img src="../../images/unicorn.jpg" ...>
>
> I guess I could use html_link_root set to "/path/to/my/nikola" but then
> my Org source loses portability.
>
> I think better would be able to explicitly state the desired URL path
> for the HTML <img> like:
>
>   #+html_url_path: /mysiteroot/images/unicorn.jpg
>   [[../images/unicorn.jpg]]
>

As I mention in my MWE, I am actually looking for a solution so that we do
not need to specify the "mysiteroot" for each link.. may be just one as a
"#+LINK_ROOT".
-- 

Kaushal Modi