External link to display image in writer exported to pdf

anotherbrian · June 28, 2020, 1:26pm

In writer, it is possible to use insert image to embed a link in the odt file. When displaying the context of the odt file via writer, writer automatically fetches the image and renders to the viewer. Of course, if internet access is down, writer cannot render the image. But the main point here is that the image was never copied - only a link to the image is stored in the odt file.

Now to pdf. Writer can be used to export to a pdf. It appears that the resultant pdf file has a copy of the image and not a link to the image. Is is possible to instead have the pdf file just store the link and then the pdf reader would render the image.

ajlittoz · June 28, 2020, 2:40pm

Answer to question 1: image link in Writer

When you insert an image with Insert>Image, enter the URL as the filename and check the box named Insert as link.

As the dump shows, a URL like http://localhost/images/image.png is stored in the document file (the same as shown in the image properties).

But I found no option tweaking in File>Export As>Export as PDF which keeps the URL. Apparently, Writer resolves the URL, retrieves the image and inserts the image into the PDF. Playing with the bookmark or link settings (to make sure it does not solve the question) has no effect.

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anotherbrian · June 28, 2020, 5:45pm

This answer is factually wrong: “I have dumped the resulting Writer document but it seems a link like http://localhost/images/image.png is not kept”.
See External link to display image in writer?
I have proved writer works as described there - the image is not stored, the image does not display if no internet, the image does display if internet is access is available.

Since the response assumes a false predicate, the second step, exporting to pdf, has not been addressed.

Please review and try again. Thx

ajlittoz · June 28, 2020, 6:01pm

@anotherbrian: OK, I made a mistake while testing. I modify my answer.

anotherbrian · June 28, 2020, 6:50pm

ok - so now we both agree that a url can be used in writer for an image and that image will render in writer when displaying to the user without the image being stored in writer odt file.

The issue is what happens when exporting to pdf? Can the URL be exported to pdf without the image being stored in pdf. There are two aspects to this question:

Does pdf standard support this - the ability to represent an image via the URL link thereby putting a burden on the pdf browser to render the image? I don’t know but I would think this would be highly desirable. So we assume it can.
Is writer able to export the URL into the pdf file without fetching the image and dumping it into pdf.

Perhaps related are export options:

General Tab: Use referenced XObjects?
Links Tab: Export URL Relative to File System set to OFF?
Other?

ajlittoz · June 28, 2020, 7:28pm

I played with all options in Links to no avail. Count them out.

mikekaganski · June 28, 2020, 8:14pm

LibreOffice does not provide this non-standardized functionality.

anotherbrian · June 30, 2020, 8:20am

Maybe it should be supported.

html supports using img-src links. this construct results in the image being rendered by the browser. at issue is when the image is copyrighted and used by a non copyright holder. one website claims “… a recent case from the Ninth Circuit Court of Appeals concluded that inline linking does not directly infringe copyright because no copy is made on the site providing the link; the link is just HTML code pointing to the image or other material.” Thus, it seems in html, it is possible to embed images of copyrighted images without infringing on the 3rd party’s copyright.

This embedding concept is supported by writer as described above. Thus, to the extent that html does not infringe upon copyright using inline links, it would appear writer does not infringe upon copyright using inline links. That this functionality is not supported by writer in the production of exporting pdf files seems like a great restriction on pdf document production using writer.

That html supports this function and writer supports this function but writer export to pdf does not, I respectfully disagree that this non standard usage.

ajlittoz · June 30, 2020, 8:47am

This is not a solution to the initial problem. It is a respectable and sound opinion, but it belongs to a comment.

Please move if after @mikekaganski’s own comment. This also will respect chronological order, which answers don’t.

Transform your disagreement into a feature request on the bugs site.

mikekaganski · June 30, 2020, 9:27am

… and in any case, PDF has its use cases, which are very different from producing something dynamically-changing. You also could argue that “not being able to link from websites seems like a great restriction on paper document production using writer”.