Wrong kerning between letters in pdf export

diolu · 06-07-2016, 04:46 AM

I try to convert an epub ebook to a printable pdf. The problem is that the kerning (spaces between letters) is bad. Some letters are too close to each other and the overall look is really uneven. This happen with many ebooks and fonts, for example the introduction ebook (that come with Calibre) to pdf with default values. Note that I have seen this problem with many word processors as well (but not with Libreoffice that do it right).

I am using Calibre in Archlinux. Both the official binary version and the version distributed by Archlinux are affected.

kovidgoyal · 06-07-2016, 05:02 AM

Turn off font hinting in your fontconfig preferences.

diolu · 06-07-2016, 05:20 AM

Quote:

Originally Posted by kovidgoyal

Turn off font hinting in your fontconfig preferences.

The kerning are wrong in the pdf, as seen on the screen (with very large magnification to examine the problem) as well as printed. Font hinting is only a technology to display character on the screen. It does not change what come out of the printer nor the spacing between letters when using a large magnification.

kovidgoyal · 06-07-2016, 05:34 AM

Sigh, the font hinting in question affects the generation of the PDF, not its display.

https://bugreports.qt.io/browse/QTBUG-44488

diolu · 06-08-2016, 04:37 AM

You are right. Disabling font hinting solves the problem. Not very handy because I have to disable it global wide each time I would like to make a pdf conversion, but it works

dimsumthinking · 05-17-2021, 10:19 AM

Hi,

I'm still seeing kerning issues in PDFs produced on a Mac only in the titles. Is there a suggested fix? This seems to be a Calibre issue as when I use another app to convert ePub to PDF I do not see this issue. I prefer to use Calibre.

Thank you,

Daniel

06-07-2016, 04:46 AM	#1
diolu Junior Member Posts: 4 Karma: 10 Join Date: Oct 2012 Device: calibre	Wrong kerning between letters in pdf export I try to convert an epub ebook to a printable pdf. The problem is that the kerning (spaces between letters) is bad. Some letters are too close to each other and the overall look is really uneven. This happen with many ebooks and fonts, for example the introduction ebook (that come with Calibre) to pdf with default values. Note that I have seen this problem with many word processors as well (but not with Libreoffice that do it right). I am using Calibre in Archlinux. Both the official binary version and the version distributed by Archlinux are affected.

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06-07-2016, 05:02 AM	#2
kovidgoyal creator of calibre Posts: 45,345 Karma: 27182818 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Turn off font hinting in your fontconfig preferences.

06-07-2016, 05:34 AM	#4
kovidgoyal creator of calibre Posts: 45,345 Karma: 27182818 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Sigh, the font hinting in question affects the generation of the PDF, not its display. https://bugreports.qt.io/browse/QTBUG-44488

06-08-2016, 04:37 AM	#5
diolu Junior Member Posts: 4 Karma: 10 Join Date: Oct 2012 Device: calibre	You are right. Disabling font hinting solves the problem. Not very handy because I have to disable it global wide each time I would like to make a pdf conversion, but it works

05-17-2021, 10:19 AM	#6
dimsumthinking Junior Member Posts: 6 Karma: 10 Join Date: Feb 2019 Device: ipad	Hi, I'm still seeing kerning issues in PDFs produced on a Mac only in the titles. Is there a suggested fix? This seems to be a Calibre issue as when I use another app to convert ePub to PDF I do not see this issue. I prefer to use Calibre. Thank you, Daniel

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