(page-break-x + feature queries + class selector) not working in CV

bookworm2000 · 07-31-2022, 09:18 AM

Hunting for what I assumed was a bug in one of my books I stumbled upon some strange behaviour in Calibre Viewer. It took me a while to identify the culprit(s) (or better, the combination thereof). I boiled it down to this test file:

Code:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops">
<head>
  <meta charset="utf-8"/>
  <title>Test</title>
  <style>
    p {
      color: red;
    }
    @supports(display: flex) {
      p {color: green;}
    }
    h1 {
      break-after: avoid;
      page-break-after: avoid;   /* delete here... */
      break-inside: avoid;
      page-break-inside: avoid;  /* ...and here... */
    }
    @supports(font-variant-numeric: oldstyle-nums) {
      p.test {color: blue;}  /* ...or remove class */
    }
  </style>
</head>
<body>
  <p class="test">Test</p>
</body>
</html>

Chrome, FF, Opera, and Edge work as expected and render blue text. Calibre Viewer only accepts the first feature query and produces the text in green.

There would be two ways two make CV understand the second query:

Delete page-break-after and page-break-inside from the completely unrelated h1 declaration (break-after and break-inside seem to be no problem).
Or, remove the class test from the p selector.

Sadly, none of these are acceptable workarounds in my case.

Tested with Calibre 6.2.1 (from PortableApps) and some old 5.x installed version on Windows 10.

kovidgoyal · 07-31-2022, 10:36 AM

That will take care of it: https://github.com/kovidgoyal/calibr...766da74f5457f4

Note that you will have to reload the book to see the fix.

bookworm2000 · 07-31-2022, 11:46 AM

Thank you!

But where should I put render_book.py? I think I tried every subdirectory of the Calibre folder.

kovidgoyal · 07-31-2022, 11:49 AM

Run calibre from source or wait for the next release.

bookworm2000 · 07-31-2022, 12:11 PM

Ah, I see. Thank you so much. I will happily wait for the next release.

07-31-2022, 09:18 AM	#1
bookworm2000 Member Posts: 14 Karma: 7220 Join Date: Dec 2012 Device: Kindle 4NT, Android	(page-break-x + feature queries + class selector) not working in CV Hunting for what I assumed was a bug in one of my books I stumbled upon some strange behaviour in Calibre Viewer. It took me a while to identify the culprit(s) (or better, the combination thereof). I boiled it down to this test file: Code: <?xml version="1.0" encoding="utf-8"?> <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops"> <head> <meta charset="utf-8"/> <title>Test</title> <style> p { color: red; } @supports(display: flex) { p {color: green;} } h1 { break-after: avoid; page-break-after: avoid; /* delete here... / break-inside: avoid; page-break-inside: avoid; / ...and here... / } @supports(font-variant-numeric: oldstyle-nums) { p.test {color: blue;} / ...or remove class / } </style> </head> <body> <p class="test">Test</p> </body> </html> Chrome, FF, Opera, and Edge work as expected and render blue text. Calibre Viewer only accepts the first feature query and produces the text in green. There would be two ways two make CV understand the second query: Delete page-break-after* and page-break-inside from the completely unrelated h1 declaration (break-after and break-inside seem to be no problem). Or, remove the class test from the p selector. Sadly, none of these are acceptable workarounds in my case. Tested with Calibre 6.2.1 (from PortableApps) and some old 5.x installed version on Windows 10. Last edited by bookworm2000; 07-31-2022 at 09:24 AM.

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07-31-2022, 10:36 AM	#2
kovidgoyal creator of calibre Posts: 43,871 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	That will take care of it: https://github.com/kovidgoyal/calibr...766da74f5457f4 Note that you will have to reload the book to see the fix.

07-31-2022, 11:46 AM	#3
bookworm2000 Member Posts: 14 Karma: 7220 Join Date: Dec 2012 Device: Kindle 4NT, Android	Thank you! But where should I put render_book.py? I think I tried every subdirectory of the Calibre folder.

07-31-2022, 11:49 AM	#4
kovidgoyal creator of calibre Posts: 43,871 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Run calibre from source or wait for the next release.

07-31-2022, 12:11 PM	#5
bookworm2000 Member Posts: 14 Karma: 7220 Join Date: Dec 2012 Device: Kindle 4NT, Android	Ah, I see. Thank you so much. I will happily wait for the next release.