1426572 - PDF viewer display character not clear at 100%

Status: NEW

(Firefox :: PDF Viewer, defect, P3)

Description

[Qiao Yongchang]

Attachment: 100p-FF58b12-win7_64bit.jpg

User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:58.0) Gecko/20100101 Firefox/58.0
Build ID: 20171218174357

Steps to reproduce:

Open a PDF file in Firefox58b12 on Windows7 64bit. And zoom 100%.
The PDF file is not scanning file. 


Actual results:

PDF viewer shows the file not clear at 100% zoom, looks like two or more character adhesion with other. I think maybe display algorithm have some problem.
Over 150% look good. 100-150% look not clear.


Expected results:

Shouldn't  appear at any zoom balance.

Comment 1

[Gingerbread Man]

Does this happen with any PDF?

Can you reproduce the problem with the latest Nightly in a brand new profile?
https://nightly.mozilla.org
https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles

Comment 2

[Qiao Yongchang]

Attachment: beta-and-nightly-screenshot.zip

attach the new screenshot.Include Firefox beta, Nightly and Chrome screenshot.

Comment 3

[Qiao Yongchang]

(In reply to Gingerbread Man from comment #1)
> Does this happen with any PDF?
> 
> Can you reproduce the problem with the latest Nightly in a brand new profile?
> https://nightly.mozilla.org
> https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-
> profiles


HI, Gingerbread :
1. I try to view another file, have this problem too, but not so obvious.

2. I had to install the Nightly version set to the safe mode and restart Nightly view same file, not clear too.

And I upload the screenshot zip to the attachment.

Thanks.

Comment 4

[Gingerbread Man]

Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:59.0) Gecko/20100101 Firefox/59.0
20171220220602

Thank you.

Please right-click the PDF page and choose Inspect Element (Q). Click the Fonts tab in the top right of the developer tools pane that opened. Click "Show all fonts used". What are all the fonts listed? For me, it's Times New Roman or Arial, Courier New, and Segoe UI.

Also, can you post a link to the file in the screenshot? I found two copies of it and they both look OK on my system.
http://poincare.matf.bg.ac.rs/~ivana//courses/ps/sistemi_knjige/pomocno/apue.pdf
https://bluetechs.files.wordpress.com/2014/03/advanced-programming-in-the-unix-environment-by-w-richard-stevens-stephen-a-rago-ii-edition.pdf

Comment 5

[Qiao Yongchang]

(In reply to Gingerbread Man from comment #4)
> Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:59.0) Gecko/20100101
> Firefox/59.0
> 20171220220602
> 
> Thank you.
> 
> Please right-click the PDF page and choose Inspect Element (Q). Click the
> Fonts tab in the top right of the developer tools pane that opened. Click
> "Show all fonts used". What are all the fonts listed? For me, it's Times New
> Roman or Arial, Courier New, and Segoe UI.
> 
> Also, can you post a link to the file in the screenshot? I found two copies
> of it and they both look OK on my system.
> http://poincare.matf.bg.ac.rs/~ivana//courses/ps/sistemi_knjige/pomocno/apue.
> pdf
> https://bluetechs.files.wordpress.com/2014/03/advanced-programming-in-the-
> unix-environment-by-w-richard-stevens-stephen-a-rago-ii-edition.pdf

My PC is Simple Chinese environment, so the default setting is Microsoft YaHei.
But I change the Firefox setting to another language, use the default setting.Open the PDF and 'Inspect Element' show all the font list :

Microsoft YaHei 系统

使用名称： "Microsoft YaHei"
Times New Roman 系统

使用名称： "Times New Roman"  

Maybe is the error Microsoft YaHei?

My download link for you to reference:
http://www.codeman.net/wp-content/uploads/2014/04/APUE-3rd.pdf

Thanks a lot.

Comment 6

[Gingerbread Man]

Attachment: Firefox59_hwaon_hwaoff.png

Thank you. Unfortunately, the Inspector doesn't provide accurate font information for PDFs. The font used is actually Palatino Linotype.

I'm seeing something similar (left), though not as severe. It actually looks nicer with hardware acceleration disabled (right).

Jonathan, does this look like an already reported bug to you? It seems not unlike bug 436954.

Comment 7

[Jonathan Kew [:jfkthame]]

It looks very similar to bug 436954, in that I think we're seeing an unhinted font, or a font whose hinting assumes one particular rasterizer's behavior and doesn't work well under an alternative rasterizer.

FWIW, it looks like the Palatino font resource embedded in that PDF was an older PostScript font, not TrueType; it's possible that the Windows/DW rasterizer doesn't always handle PS hinting well, or the hinting was stripped during font embedding, or something... (I haven't attempted to actually extract the font resources for examination).

Comment 8

[Brendan Dahl [:bdahl]]

I haven't looked to deeply at this specific PDF/font, but PDF.js does remove some hinting so that I likely the cause.