grawity@ - Thanks for filing the issue...!!

Could you please provide a sample test document/url to test the issue from TE-end.
This will help us in triaging the issue further.

Thanks...!!

I can reproduce it with any document, even as simple as this:

<p style="font: 12pt Cambria">Hello world!</p>

...as long as the font is installed. (I copied C:\Windows\Fonts\Cambria* from Windows 10 to ~/.local/share/fonts/ on Linux.)

And, forgot to mention the library versions Arch uses:

extra/fontconfig 2.12.6+5+g665584a-1
extra/freetype2  2.8.1-1

(Not sure if the official Google binaries use system libraries or ship their own...)

Thank you for providing more feedback. Adding requester "krajshree@chromium.org" to the cc list and removing "Needs-Feedback" label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

grawity@ - Thanks for your help...!!

Tried testing the issue on Ubuntu 14.04 using chrome reported version #63.0.3239.108 by copying the fonts at C:\Windows\Fonts\Cambria* from Windows 10 to ~/.local/share/fonts/ on Linux, but permission was denied even after modifying the permission using chmod command.
Hence, tried method #2, from url: http://www.aboutlinux.info/2005/12/adding-windows-fonts-in-linux.html
Opened the document provided at comment #6 and observed that chrome used non-antialiased embedded bitmaps for the text as in "2017-12-12.191658.Chromium63.png". This behaviour is same in M-62 and in M-50 also.
Attached screen shots for reference.

Could you please let us know if it the the correct way to proceed with testing. Please guide us with your inputs.

Thanks...!!

Deleted: 797496_M63.png 160 KB

	797496_M63.png 160 KB View Download

Deleted: 797496@M62.png 154 KB

	797496@M62.png 154 KB View Download

Well, yeah, the embedded bitmap feature is enabled by default in Linux's fontconfig :(

But in this bug report, I am *disabling* this via ~/.config/fontconfig/fonts.conf (attached), and 62 honors this setting but 63 does not.

Deleted: fonts.conf 555 bytes

fonts.conf 555 bytes Download

Thank you for providing more feedback. Adding requester "krajshree@chromium.org" to the cc list and removing "Needs-Feedback" label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Able to reproduce the issue on Ubuntu 14.04 using chrome reported version #63.0.3239.108 and latest dev #65.0.3306.0.

Bisect Information:
=====================
Good build: 63.0.3234.0    Revision(506936)
Bad Build : 63.0.3235.0    Revision(507234)

Change Log URL: 
https://chromium.googlesource.com/chromium/src/+log/80f8312df3cc9c0f24600b0e7fe27bca1cd64785..a4eab4fa86aa0f2a0be6ef7234687b70c7a02f95

From the above change log suspecting below change
Change-Id: I3e11df05fab9b0fdc465c97c4b2f7579b5403723
Reviewed-on: https://chromium-review.googlesource.com/702422

drott@ - Could you please check whether this is caused with respect to your change, if not please help us in assigning it to the right owner.
Note: Adding stable blocker for M-63 as it seems to be a recent regression. Please feel free to remove the same if not appropriate.

Thanks...!!

This is a side effect of an important change to improve rendering of the Calibri font on Windows. The Calibri font has bitmap strikes for Latin text which collide with subpixel rendering and lead to uneven spacing. Compare https://chromium-review.googlesource.com/702422 and  issue 707713 .

I am not exactly sure how this CL causes this regression side effect - that needs more investigation and we should be able to fix it.

However, since this is a custom fontconfig configuration and custom installed font on Linux, it does not affect a large number of users and I would thus not consider it RB-Stable.

> The Calibri font has bitmap strikes for Latin text which collide with subpixel rendering and lead to uneven spacing

Right, and Cambria has bitmaps as well – we're both trying to disable the same thing. But Chrome's fix to disable bitmaps for Calibri accidentally ended up force-*enabling* those bitmaps for other fonts, with noticeably bad results.

Looking at it, the problem seems to be in FontPlatformData{Linux,Win}.cpp:

    paint->setEmbeddedBitmapText(!avoid_embedded_bitmaps_);

Instead, it should only disable the option, but never enable it:

    if (avoid_embedded_bitmaps_) {
        paint->setEmbeddedBitmapText(false);
    }

Thanks, now I see clearer, I did read your initial report the wrong way around. and had assumed you'd like to enable them. Your fix proposal seems reasonable, we can try with that, plus adding Cambria to the list of fonts not to use bitmaps from. 

...Not sure if that meant I should write the patch, but here you go anyway: https://crrev.com/c/861562

Thanks for the CL - I've started on it, the tricky part is developing a regression test by creating an open license font file which has both bitmap glyphs and TrueType outlines. We do have the beginnings of such a test in https://cs.chromium.org/chromium/src/third_party/WebKit/LayoutTests/fast/text/chromium-linux-fontconfig-renderstyle.html?q=fontconfig+LayoutTests&sq=package:chromium&dr=C&l=23 - unfortunately, this one did not cover the bitmap case so far.

drott@ Any chance you could fix the bug without needing the full regression testing? Perfect is the enemy of good, after all. 😉