birdie-github commented 5 years ago

Attach (recommended) or Link to PDF file here: http://us.download.nvidia.com/Windows/361.43/361.43-win10-win8-win7-winvista-desktop-release-notes.pdf

Configuration:

Web browser and its version: Firefox 68 beta 6
Operating system and its version: Fedora 30 fully updated + proprietary NVIDIA drivers
PDF.js version: no idea
Is a browser extension: no

Steps to reproduce the problem:

Open this PDF

What is the expected behavior? (add screenshot) (Google Chrome on the same PC) chrome

What went wrong? (add screenshot)

Wrong (varying) spacing between letters
Wrong strokes width
Bad kerning

notfixed

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

Snuffleupagus commented 5 years ago

Duplicate of #2739.

birdie-github commented 5 years ago

2739 was closed and never fully fixed.

birdie-github commented 5 years ago

And this is how it should look like (Adobe Reader under Windows):

adobe_reader

At 100% and without local fonts for true comparison:

adobe_reader_100p

Snuffleupagus commented 5 years ago

2739 was closed and never fully fixed.

Please see https://github.com/mozilla/pdf.js/issues/2739#issuecomment-450633930:

This PDF file looks good now on Arch Linux, i.e., it renders exactly the same in PDF.js for me as it does in Okular. Since the file does not embed its fonts, there is not much more we can do here.

birdie-github commented 5 years ago

Arch Linux is not the Linux. Fedora is also very popular. There are literally hundreds of thousands of people who use NVIDIA proprietary drivers under Linux. It's not the reason to say "there is not much more we can do here".

You're pretty much saying, "We couldn't care less about a large number of Linux users because in our very particular distro under very particular graphics drivers it just works". No, it doesn't.

If you need any data from me, like drivers versions, libraries version, etc. I can readily provide it.

Also, where's your screenshot? It's not like I don't believe you - more like there are three different issues listed under this bug report and it doesn't seem likely that you're not affected by any of them.

automatedbugreportingfacility commented 5 years ago

This also seems to affect Windows 10 (1809) + nVidia drivers:

Sorry for the noob question, but if the font isn't embedded, where does PDFium fetch it from in Chromium?

Snuffleupagus commented 5 years ago

Since the file does not embed its fonts, there is not much more we can do here.

The PDF file itself does not embed all of its fonts, which is a deprecated practice in the specification (because of font substitution issues similar to this one), and the PDF.js library is thus at the mercy of the platform/operating system to provide some reasonable default standard font.

automatedbugreportingfacility commented 5 years ago

Yes, I know the font should be included in the PDF file, but the underlying OS providing the default standard font (Windows 10 1809) is the same for Chromium and Firefox Nightly, hence the question. Does PDFium come with some predefined set of fonts potentially unavailable in operating systems? Also, spacing seems to look better when PDF.js is running in Chromium (the screenshot I posted in the previous comment is from Nightly):

timvandermeij commented 5 years ago

I'm not really sure how to proceed here. For me it looks exactly like the second screenshot in https://github.com/mozilla/pdf.js/issues/10878#issuecomment-498026964. Yes, it's a substituted font, but if the PDF file doesn't embed the fonts, we can only fall back to a close substitute as explained in https://github.com/mozilla/pdf.js/issues/10878#issuecomment-498048215. We could try to look into why it's not the same substitute as in Chrome, but it will always be a substitute and is likely to differ between operating systems and platforms.

You're pretty much saying, "We couldn't care less [...]"

@birdie-github That's not true. If there is in fact something that can still be done about this or if there was an oversight, we're always willing to reopen issues (which we do now because I think the question is https://github.com/mozilla/pdf.js/issues/10878#issuecomment-498177749 is a good question), but only if the discussion is constructive. Remember that most people here help out in their spare time.

automatedbugreportingfacility commented 5 years ago

FWIW, PDFium matches what Adobe Acrobat Reader DC displays on the same system (fresh VBox VM for Windows 10):

timvandermeij commented 5 years ago

Thank you for making the comparison. Here I also see some differences between Adobe Acrobat Reader DC and PDFium, in particular the "December 21, 2015" text where the "5" character looks thicker (more bold) than in PDFium, but you're right that especially the large white text looks better in those two applications than in PDF.js.

birdie-github commented 5 years ago

Another PDF with a completely broken kerning:

http://pascal.hansotten.com/uploads/docs/euler%20stanford%20CS-TR-65-20.pdf

Firefox 68 beta 13 vs Google Chrome:

firefox68_vs_chrome