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Issue 633478 link

Starred by 2 users

Issue metadata

Status: Fixed
Owner:
Closed: Aug 2016
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Windows
Pri: 2
Type: Bug

Blocking:
issue 630917
issue 545643



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Text is rendered by doubling pixels on hi-dpi screen for some fonts

Project Member Reported by kojii@chromium.org, Aug 2 2016

Issue description

Text rendering is much worse in hi-dpi than in lo-dpi. It looks like they're rendered in lo-dpi then doubled pixels.

3 fonts are known to hit this condition:
- Yu Gothic
- Noto Sans CJK
- Myriad Set Pro

All these fonts render poorly in lo-dpi too, so we keep  issue 545643  and 630917 to track them, but the poorness in hi-dpi is very noticeable.

Screenshots are Chrome, Edge, Firefox from left.
Reproducing HTML
  http://output.jsbin.com/heneyo for Yu Gothic/Noto Sans CJK
  https://webkit.org/status for Myriad Set Pro

fmalita@, could you advice me where this belong to? Is this paint or Skia, or something else?

 

Comment 1 by kojii@chromium.org, Aug 2 2016

yu-gothic-hidpi-chrome-edge-firefox.png
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noto-hidpi-chrome-edge-firefox.png
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Myriad-Set-Pro-hidpi-chrome-edge-firefox.png
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Cc: osh...@chromium.org
Owner: kojii@chromium.org
+oshima.

Checking with a magnifier, I'm guessing that the rasterized content layer is post-filtered - either because of a fractional layer (http://crbug.com/521364) or general positioning/scaling funkiness for DSF != 1.  So it's probably CC/paint, not Skia (but bungeman should double-check).

Can you try launching with --enable-use-zoom-for-dsf?  There's a good chance that http://crbug.com/485650 will solve this.  It certainly makes things crisper in Linux, but I don't have a Win box handy to try.
Cc: fmalita@chromium.org
Cc: bsep@chromium.org
Which version is it? bsep@ enabled this mode on windows in 53.

Comment 5 by kojii@chromium.org, Aug 8 2016

#4: Which version is it? bsep@ enabled this mode on windows in 53.

Canary, can reproduce on 54.0.2802.0

Comment 6 by kojii@chromium.org, Aug 8 2016

#2: --enable-use-zoom-for-dsf doesn't seem to change the result.

Comment 7 by kojii@chromium.org, Aug 8 2016

Oh, wait, 54.0.2823.0 changed something dramatically. This issue is gone, now these fonts look as hi-res as Edge, though everything is lighter, including border and 'Courier New' (fonts in this page) only in Hi-DPI.
yu-gothic-hidpi-chrome-edge-54.0.2823.0.png
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Courier-New-hidpi-chrome-edge-54.0.2823.0.png
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Comment 8 by kojii@chromium.org, Aug 9 2016

Status: Fixed (was: Assigned)
Verified other cases too and hi-dpi double-pixel problem was resolved. Tried some but can't find which CL fixed this, mark as fixed anyway.

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