Weblog entry #422 for simonw
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#422
Printing to PDF - a minor kerning issue?
Posted by simonw on Tue 14 Jun 2011 at 18:37
It started as looking at an issue with running wkhtmltopdf on Squeeze and poor quality text.
Noted that if I print a PDF from a web page using the "Print to File" option on my KDE desktop using Debian Squeeze I get the same issue (or visually similar issue suggesting the issue is lower in the stack than wkhtmltopdf) in the PDF.
Convinced myself it isn't entirely a kerning issue in Evince (which seems to be the best PDF viewer available in Squeeze) by printing the PDF and still showing the same issue in the printed copy (so after pdftops presumably).
This bug seemed relevant but the problem isn't THAT bad, and affects content more than titles. But it could be another manifestation of the same bug.
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=556867
"Kate" seems to print boring old text to PDF just fine on the few cases I've tested but some pages from Firefox and Chrome seem to just space the letters in an ugly fashion - the ugliness is similar in both browsers although it isn't always the same place on the web page in each browser that go ugly, but then there are slight difference in the rendering and printing so not surprising spacing isn't identical (although it is pretty close between the browsers).
Anyone any ideas on this before I raise a bug, or comment on the existing one? I could do with a refresher of "Print to File". I presume this uses the cups-pdf driver which use to require you to install a specific PPD. But presumably the issue lies either in a lower layer yet (Cairo) or in how that lower level in invoked. Can I inspect fonts to get an overview of hinting information, as I understand the behviour can change with resolution (does this apply to creating PDFs?).
Hard to give specific examples as I think somethings are rendering issues.
This URL works fine:
https://developer.mozilla.org/samples/cssref/font-family.html
This one the text in the Google Ad I got mangled (Words "Document Management" the "g" and "e" are too close together when viewed in evince at 200%, but viewed at other zoom levels the text is fine. So is that the same issue, or is that an evince rendering issue? There are so many layer affecting all this that it is hard to rip them away with confidence (unless I guess you are use to working in this field).
http://www.loadpdf.com/ebook/debian-guide.html
Noted that if I print a PDF from a web page using the "Print to File" option on my KDE desktop using Debian Squeeze I get the same issue (or visually similar issue suggesting the issue is lower in the stack than wkhtmltopdf) in the PDF.
Convinced myself it isn't entirely a kerning issue in Evince (which seems to be the best PDF viewer available in Squeeze) by printing the PDF and still showing the same issue in the printed copy (so after pdftops presumably).
This bug seemed relevant but the problem isn't THAT bad, and affects content more than titles. But it could be another manifestation of the same bug.
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=556867
"Kate" seems to print boring old text to PDF just fine on the few cases I've tested but some pages from Firefox and Chrome seem to just space the letters in an ugly fashion - the ugliness is similar in both browsers although it isn't always the same place on the web page in each browser that go ugly, but then there are slight difference in the rendering and printing so not surprising spacing isn't identical (although it is pretty close between the browsers).
Anyone any ideas on this before I raise a bug, or comment on the existing one? I could do with a refresher of "Print to File". I presume this uses the cups-pdf driver which use to require you to install a specific PPD. But presumably the issue lies either in a lower layer yet (Cairo) or in how that lower level in invoked. Can I inspect fonts to get an overview of hinting information, as I understand the behviour can change with resolution (does this apply to creating PDFs?).
Hard to give specific examples as I think somethings are rendering issues.
This URL works fine:
https://developer.mozilla.org/samples/cssref/font-family.html
This one the text in the Google Ad I got mangled (Words "Document Management" the "g" and "e" are too close together when viewed in evince at 200%, but viewed at other zoom levels the text is fine. So is that the same issue, or is that an evince rendering issue? There are so many layer affecting all this that it is hard to rip them away with confidence (unless I guess you are use to working in this field).
http://www.loadpdf.com/ebook/debian-guide.html
Comments on this Entry
Safari has same bug
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See the same issue in Windows XP with Chrome.
Some reports from wkhtmltopdf list that Mac's are better.
Perhaps I'll try Safari on Windows to see if WebKit is the likely culprit.
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