Subsetting fonts problem when using pseudo-classes

jackie_w · 09-24-2022, 12:28 PM

I was hoping to use existing code from calibre.ebooks.oeb.polish.subset, specifically subset_all_fonts, to build some extra functionality into one of my personal plugins.

The problem I'm seeing is that text which will be displayed by a CSS rule such as:

Code:

.tx1::first-line {font-family: MySmallcapsFont;}

doesn't seem to be taken into account when the existing subsetting code is deciding which characters need to be retained in the MySmallcapsFont font. In the worst-case scenario, if the above CSS rule was the only one referencing MySmallcapsFont then currently this font would be completely removed from the container.

I do understand that calibre has no idea which/how many characters will appear on the first-line but I wonder if it's possible to have some sort of compromise, i.e. keep all characters used by class="tx1", i.e. the main part of the selector. Just a personal opinion but I'd rather keep too many than too few.

If this is a non-starter then I'll just have to live with it, but if it's something you'd consider fixing/improving I'm happy to open a bug report with a sample epub.

kovidgoyal · 09-24-2022, 11:21 PM

Sure, sounds reasonable. Go ahead and open the bug report.

jackie_w · 09-25-2022, 08:33 AM

Quote:

Originally Posted by kovidgoyal

Sure, sounds reasonable. Go ahead and open the bug report.

Thanks. Opened here.

jackie_w · 09-28-2022, 06:41 PM

Many thanks for fixing this.

kovidgoyal · 09-28-2022, 11:36 PM

You are welcome

09-24-2022, 12:28 PM	#1
jackie_w Grand Sorcerer Posts: 6,212 Karma: 16534894 Join Date: Sep 2009 Location: UK Device: Kobo: KA1, ClaraHD, Forma, Libra2, Clara2E. PocketBook: TouchHD3	Subsetting fonts problem when using pseudo-classes I was hoping to use existing code from calibre.ebooks.oeb.polish.subset, specifically subset_all_fonts, to build some extra functionality into one of my personal plugins. The problem I'm seeing is that text which will be displayed by a CSS rule such as: Code: .tx1::first-line {font-family: MySmallcapsFont;} doesn't seem to be taken into account when the existing subsetting code is deciding which characters need to be retained in the MySmallcapsFont font. In the worst-case scenario, if the above CSS rule was the only one referencing MySmallcapsFont then currently this font would be completely removed from the container. I do understand that calibre has no idea which/how many characters will appear on the first-line but I wonder if it's possible to have some sort of compromise, i.e. keep all characters used by class="tx1", i.e. the main part of the selector. Just a personal opinion but I'd rather keep too many than too few. If this is a non-starter then I'll just have to live with it, but if it's something you'd consider fixing/improving I'm happy to open a bug report with a sample epub.

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09-24-2022, 11:21 PM	#2
kovidgoyal creator of calibre Posts: 44,017 Karma: 22669822 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Sure, sounds reasonable. Go ahead and open the bug report.

09-28-2022, 06:41 PM	#4
jackie_w Grand Sorcerer Posts: 6,212 Karma: 16534894 Join Date: Sep 2009 Location: UK Device: Kobo: KA1, ClaraHD, Forma, Libra2, Clara2E. PocketBook: TouchHD3	Many thanks for fixing this.

09-28-2022, 11:36 PM	#5
kovidgoyal creator of calibre Posts: 44,017 Karma: 22669822 Join Date: Oct 2006 Location: Mumbai, India Device: Various	You are welcome