Calibre can't link to images or pdfs?

bdoors · 11-20-2023, 01:51 AM

This valid code is in my HTML file that I submit as input to Calibre --

<a href="test.pdf">Test PDF</a>
<a href="test.jpg">Test JPG</a>

After I convert my input to EPUB and edit it, I see that Calibre has translated my input lines into this-

<a href="test.pdf" class="pcalibre calibre5 pcalibre1">Test PDF</a>
<a href="test.jpg" class="pcalibre calibre5 pcalibre1">Test JPG</a>

When I'm in the Calibre Reader and try to click on my links, Calibre brings up the browser and gives me these error messages --

https://calibre-internal.invalid/test.pdf
https://calibre-internal.invalid/test.jpg

Is Calibre not capable of displaying a linked image or PDF file?

Or am I doing something wrong?

Thank you.

BetterRed · 11-20-2023, 03:52 AM

AFAIK those aref clauses are not valid because "test.pdf" is not a well-formed URL.

See [W3School] HTML a href Attribute

BR

bdoors · 11-20-2023, 11:05 AM

Thank you, BR, for your help.

I see what you're saying -- in the phrase

<a href="subject">link_name</a>

the "subject" must be an html file, not a jpg or pdf file.

I was coding with jpg and pdf as "subjects" because it passes html validation just fine. And works in the two browsers I test with.

But it doesn't work when I generate an EPUB through Calibre.

Through research I found that now html officially does allow jpg and pdf files to act as subjects, just by adding the download keyword --

<a href="test.jpg" download>link_name</a>

But his didn't work in Calibre either.

For now, it looks like my solution for Calibre should be to embed those jpg and pdf files within an html file. Then refer to the html file as the subject in my link.

(PS-- this is no knock on Calibre, it is a fantastic tool I am very grateful for.)

Quoth · 11-20-2023, 02:54 PM

Ebooks use HTML and CSS, but they don't support all the stuff that websites do.
Putting an HTML "wrapper" is best, but a PDF is a terrible thing to put in an ebook.

bdoors · 11-21-2023, 11:48 AM

Thanks for the tip, Quoth. I looked at a few PDFs on my mobile and, like you said, they looked pretty bad. I tried on a bigger phone and got a decent result when turning the phone sideways, but you're right, PDFs seem to range from "a little awkward" to hardly readable.

So I converted my PDFs to html. Looks way better and fits Calibre, too.

I only had a few files, so I converted manually. (If I had more files, I might have tried out the free tool pdf2htmlEX at Github.)

Cheers.

11-20-2023, 01:51 AM	#1
bdoors Junior Member Posts: 5 Karma: 10 Join Date: Nov 2023 Device: none	Calibre can't link to images or pdfs? This valid code is in my HTML file that I submit as input to Calibre -- <a href="test.pdf">Test PDF</a> <a href="test.jpg">Test JPG</a> After I convert my input to EPUB and edit it, I see that Calibre has translated my input lines into this- <a href="test.pdf" class="pcalibre calibre5 pcalibre1">Test PDF</a> <a href="test.jpg" class="pcalibre calibre5 pcalibre1">Test JPG</a> When I'm in the Calibre Reader and try to click on my links, Calibre brings up the browser and gives me these error messages -- https://calibre-internal.invalid/test.pdf https://calibre-internal.invalid/test.jpg Is Calibre not capable of displaying a linked image or PDF file? Or am I doing something wrong? Thank you.

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11-20-2023, 03:52 AM	#2
BetterRed null operator (he/him) Posts: 20,628 Karma: 26960534 Join Date: Mar 2012 Location: Sydney Australia Device: none	AFAIK those aref clauses are not valid because "test.pdf" is not a well-formed URL. See [W3School] HTML a href Attribute BR

11-20-2023, 11:05 AM	#3
bdoors Junior Member Posts: 5 Karma: 10 Join Date: Nov 2023 Device: none	Thank you, BR, for your help. I see what you're saying -- in the phrase <a href="subject">link_name</a> the "subject" must be an html file, not a jpg or pdf file. I was coding with jpg and pdf as "subjects" because it passes html validation just fine. And works in the two browsers I test with. But it doesn't work when I generate an EPUB through Calibre. Through research I found that now html officially does allow jpg and pdf files to act as subjects, just by adding the download keyword -- <a href="test.jpg" download>link_name</a> But his didn't work in Calibre either. For now, it looks like my solution for Calibre should be to embed those jpg and pdf files within an html file. Then refer to the html file as the subject in my link. (PS-- this is no knock on Calibre, it is a fantastic tool I am very grateful for.)

11-20-2023, 02:54 PM	#4
Quoth the rook, bossing Never. Posts: 11,343 Karma: 85874895 Join Date: Jun 2017 Location: Ireland Device: All 4 Kinds: epub eink, Kindle, android eink, NxtPaper11	Ebooks use HTML and CSS, but they don't support all the stuff that websites do. Putting an HTML "wrapper" is best, but a PDF is a terrible thing to put in an ebook.

11-21-2023, 11:48 AM	#5
bdoors Junior Member Posts: 5 Karma: 10 Join Date: Nov 2023 Device: none	Thanks for the tip, Quoth. I looked at a few PDFs on my mobile and, like you said, they looked pretty bad. I tried on a bigger phone and got a decent result when turning the phone sideways, but you're right, PDFs seem to range from "a little awkward" to hardly readable. So I converted my PDFs to html. Looks way better and fits Calibre, too. I only had a few files, so I converted manually. (If I had more files, I might have tried out the free tool pdf2htmlEX at Github.) Cheers.