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Issue 656794 link

Starred by 2 users
Status: WontFix
Owner:
fmalita@chromium.org
Closed: Nov 2016
Cc:
█ reed@chromium.org
fmalita@chromium.org
e...@chromium.org
█ sureshkumari@chromium.org
█ mbarowsky+blinkimage@chromium.org
Components:
EstimatedDays: ----
NextAction: ----
OS: Windows , Mac
Pri: 2
Type: Bug



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Suspiciously blurry hero image as the browser window is resized

Project Member Reported by dpranke@chromium.org, Oct 17 2016 
In the following web page:

http://77.104.139.216/~suscon21/homepages/photosize.html

The main hero image (of the two farmers) seems suspiciously more blurry at some screen sizes in Chrome than it does in Safari.

For example, if you use a window width of 1290px, the image to my eyes looks equally crisp in both browsers, but if you shrink the window down to of 1121px, the Chrome image looks blurrier than the Safari one.

Am I seeing things, or is this correct, and if so, is this WAI or is there something we could be doing to make things less blurry?

(This is similar to, but perhaps not the same as,  bug 656784 , which I also just filed).

Comment 1 by sureshkumari@chromium.org, Oct 18 2016

Cc: sureshkumari@chromium.org
Labels: Needs-Feedback OS-Windows
Tested on windows-10, Mac-10.12 using chrome stable version 54.0.2840.59 and canary 56.0.2894.0.Unable to reproduce the issue with below steps
1.0pened chrome browser
2.opened "http://77.104.139.216/~suscon21/homepages/photosize.html
3.observed clear image with width of 1290px 
4.shrink the window down to of 1121px-observed clear image
5.0pened Safari browser
6.Repeated steps from 2 to 4
7.Observed same image quality in both (chrome & safari) browsers.


Please find the attached screenshots for reference and let me know if i miss anything to reproduce the issue.
safari screenshot.png
3.5 MB View Download
chrome screenshot.png
4.1 MB View Download

Comment 2 by chrishtr@chromium.org, Oct 18 2016 

For me, Safari also looks blurry at some scales on OS X / Retina. I'm not at
all sure what can be done about this either, as any algorithm change probably
will have side-effects. Florin WDYT?

Comment 3 by fmalita@chromium.org, Oct 18 2016 

I can't really notice the blurriness on Linux, but I see the background image size is 1200x765, where the width is suspiciously close to the threshold mentioned.

So maybe the difference is due to the different scaling algorithms we use when upscaling vs. downscaling (bicubic + bilerp vs. mipmaps + bilerp).  I would speculate that upscaling is sharper because bilerp is only applied for residual/subpixel scale (stretched by < 1px), whereas for downscaling we bilerp to the nearest mip level.  It's also expected that when the dest rect happens to be perfectly pixel-aligned with the prescaled image/mip, the result should be much nicer (because we essentially skip the secondary bilerp).

I had an old CL which dropped quality to plain bilerp (no mip maps or bicubic filtering) if the dest rect was not pixel aligned with the prescaled image.  I suspect that would produce the most contrast, and this looks like the sort of image which benefits from contrast/sharpness.  But yeah, that would likely have lots of side effects.

Comment 4 by schenney@chromium.org, Nov 7 2016

Labels: -Needs-Feedback
Owner: fmalita@chromium.org
Status: Assigned (was: Unconfirmed)
chrishtr@, could you respond to fmalita@ about whether this is actionable? Otherwise we should close.

Comment 5 by chrishtr@chromium.org, Nov 7 2016

Status: WontFix (was: Assigned)
►

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