Font subsetting problem

yktan · 09-18-2013, 11:26 PM

Hi, I am trying to convert a html file to epub/azw3 format. I can embed a font without any problems but when I try to subset the font, some of the characters are messed up.

It looks like calibre is choosing the wrong glyphs during the subsetting process. I exploded the epub with the subsetted font and perform the following troubleshooting:
(1) Removed the font-face css and viewed the page with Firefox and it displays correctly with system default font. That means the character encoding is still correct.
(2) Replaced the font file (tff) with the full font file, the page displays correctly as well.

Can you investigate if it is a bug in the font subsetting process?

kovidgoyal · 09-19-2013, 12:02 AM

I opened both the original and the subset font file in font forge and as far as I can see the glyphs are the same, I checked the glyphs for uni4E00, uni4EBA and a couple of other random ones.

Given that I dont have much experience with CJK fonts, it's possible I may be missing something else, but I cant see what.

yktan · 09-19-2013, 12:17 AM

Could you check for uni5E74, uni6C11 or uni6CB3? For some reason FontForge doesn't want to run on my laptop.

kovidgoyal · 09-19-2013, 12:35 AM

On second thoughts, I think I see where the problem might be, I will investigate further.

kovidgoyal · 09-19-2013, 03:11 AM

https://github.com/kovidgoyal/calibr...e801df36509802

yktan · 09-19-2013, 11:00 PM

Thanks very much for the quick fix!

09-18-2013, 11:26 PM	#1
yktan Junior Member Posts: 5 Karma: 10 Join Date: Sep 2011 Device: Android smartphones	Font subsetting problem Hi, I am trying to convert a html file to epub/azw3 format. I can embed a font without any problems but when I try to subset the font, some of the characters are messed up. It looks like calibre is choosing the wrong glyphs during the subsetting process. I exploded the epub with the subsetted font and perform the following troubleshooting: (1) Removed the font-face css and viewed the page with Firefox and it displays correctly with system default font. That means the character encoding is still correct. (2) Replaced the font file (tff) with the full font file, the page displays correctly as well. Can you investigate if it is a bug in the font subsetting process? Last edited by yktan; 09-19-2013 at 11:01 PM.

09-19-2013, 12:17 AM	#3
yktan Junior Member Posts: 5 Karma: 10 Join Date: Sep 2011 Device: Android smartphones	certain words Could you check for uni5E74, uni6C11 or uni6CB3? For some reason FontForge doesn't want to run on my laptop.

09-19-2013, 11:00 PM	#6
yktan Junior Member Posts: 5 Karma: 10 Join Date: Sep 2011 Device: Android smartphones	Thanks! Thanks very much for the quick fix!

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09-19-2013, 12:02 AM	#2
kovidgoyal creator of calibre Posts: 43,860 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	I opened both the original and the subset font file in font forge and as far as I can see the glyphs are the same, I checked the glyphs for uni4E00, uni4EBA and a couple of other random ones. Given that I dont have much experience with CJK fonts, it's possible I may be missing something else, but I cant see what.

09-19-2013, 12:35 AM	#4
kovidgoyal creator of calibre Posts: 43,860 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	On second thoughts, I think I see where the problem might be, I will investigate further.

09-19-2013, 03:11 AM	#5
kovidgoyal creator of calibre Posts: 43,860 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	https://github.com/kovidgoyal/calibr...e801df36509802

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