Quick Look having zoom issues with PNG files. I swear this didn't happen with my High Sierra MBP, but I'm noticing it in my current Sonoma Mini M2

[saldin]

Zooming in on PNG images with Quick Look is broken for me. Is this happening to others? Thanks in advance!

I tested it by creating a 5000x5000 white canvas in GIMP, adding the test letters "X O" in the middle at 92 point size, and exporting it as PNG and JPG (100% quality). After that, I invoked Quick Look and zoomed in on the text.

This is the result:

Opening the file with Preview and zooming in looks correct, so the problem appears to be isolated to Quick Look's PNG plugin:

Before my current Mini M2, I had a MBP2011 on High Sierra and I clearly remember this was not a problem there. All zoom worked correctly for any file type. I haven't tested more file types, but I'm compelled to test a few more, like GIF, PSD, EPS, etc.

I cannot attach my test file because even though it's 120 KB, the canvas size is 5000x5000.

 

[saldin]

Tried a few more file types.

OK: BMP, TIF, PSD, and HEIC

Not OK: GIF, PDF, and WEBP. I expect the PDF example to look bad if the conversion reduced the image size and/or applied lossy compression, but I'm not a GIMP expert and cannot say this was the case.

And even though the image wasn't correctly rendered in these cases, it still wasn't as god-awfully bad as the PNG Quick Look example...

 

[saldin]

I'm feeling a bit let down, because even though the Apple Silicon hardware is great, the Mac OS evolution has not been all that great in my eyes, and I've been spotting things all around that have become less reliable, instead of more.

 

[gilby101]

I tested it by creating a 5000x5000 white canvas in GIMP

I suspect that GIMP is your problem, or your use of it. All looks good for a PNG exported from PS.

 

[Sciuriware]

I'm feeling a bit let down, because even though the Apple Silicon hardware is great, the Mac OS evolution has not been all that great in my eyes, and I've been spotting things all around that have become less reliable, instead of more.

GIMP is a huge program, very complicated and with enough settings to study a lifetime on it.
So, for many years I used IrfanView for MSWindows in emulation.
Since I am replacing my hardware by Silicon, I wrote my own stuff in JAVA.
For you: the APPSTORE is full of alternatives that are simple enough.
;JOOP!

 

[saldin]

I suspect that GIMP is your problem, or your use of it. All looks good for a PNG exported from PS.

I don't have PS. Can you share your test file with me here, please?

My test file was 5000x5000 because I noticed the problem appears when zooming past a certain point, like if the PNG Quick Look plugin puts a hard cap on the viewing resolution without any regard for the actual image resolution.

I did another test with only Mac OS system tools: I opened the MacRumors logo and zoomed in. Because it's SVG, it retained its clean lines, and then screenshotted it using Mac OS' own tool which saved it as PNG. Then I exported a copy as JPG with full quality in Preview.

The result is repeatable with Mac OS' own tools instead of GIMP, but I still have the nagging feeling the problem may be Quick Look on my Mini...

 

[saldin]

GIMP is a huge program, very complicated and with enough settings to study a lifetime on it.
So, for many years I used IrfanView for MSWindows in emulation.
Since I am replacing my hardware by Silicon, I wrote my own stuff in JAVA.
For you: the APPSTORE is full of alternatives that are simple enough.
;JOOP!

I'm not saying it just for this problem. I've had issues with my monitor, networking, Quick View, USB devices, application integrations, and many more things. Things I never had any issues with my older Macs with older Mac OS versions, and that's the impression that I get, that even though things work mostly right most of the time, that the little details are not being cared for to ensure a polished experience.

 

[Sciuriware]

I'm not saying it just for this problem. I've had issues with my monitor, networking, Quick View, USB devices, application integrations, and many more things. Things I never had any issues with my older Macs with older Mac OS versions, and that's the impression that I get, that even though things work mostly right most of the time, that the little details are not being cared for to ensure a polished experience.

Stupid question: do the pictures look right in GIMP?
;JOOP!

 

[saldin]

Stupid question: do the pictures look right in GIMP?
;JOOP!

Zooming performs correctly when the files are opened in GIMP and in Preview, but they're not the problem, it's Quick Look

 

[saldin]

Got help from a friend with a MacBook Pro M1 and the results were the same: some Quick Look plug-ins do not behave as expected and fail to deliver required quality. Screenshots attached.

 

[saldin]

Screenshots were taking with Sonoma 14.5, tested and confirmed the problem persisted in 14.6 and 14.6.1.

Upgraded to Sequoia 15.0 and the problem remains.

 

[zevrix]

Screenshots were taking with Sonoma 14.5, tested and confirmed the problem persisted in 14.6 and 14.6.1.

Upgraded to Sequoia 15.0 and the problem remains.

I'm sure I'm missing something, but what specifically is the problem?

All I see is two badly pixelated images: one png and another is jpeg.

Or the problem is that QuickLooks smoothes the pixelation in png?

I assume that this image is zoomed at a few hundred percent? Or is this the original size?

 

[saldin]

View attachment 2424975


I'm sure I'm missing something, but what specifically is the problem?

All I see is two badly pixelated images: one png and another is jpeg.

Or the problem is that QuickLooks smoothes the pixelation in png?

I assume that this image is zoomed at a few hundred percent? Or is this the original size?

The problem is that, for high resolution images that are several thousand pixels on each axis, it's not even possible to zoom to 100% when Quick Looking an image that's one of the affected file formats (PNG being one, and the worst example). Quick Look is THAT broken.

The example files are PNG and JPEG image of the MacRumors logo in high resolution (about 5000px) and are effectively similar, bar JPEG being a lossy format and PNG not.

What I think it's happening is that when Quick Looking high resolution images in certain file formats, there is a hard limit to the zoom factor that's set much below 100% (there's likely a hard limit resolution-wise), and continuing past that point (that, again, it's well below 100%) has Quick Look start to zoom with supersampling which causes the noticeable smoothing. Zooming several hundred percent would have to show the clearly defined individual pixels, which happens for the JPG example but not the PNG example which shows a very smoothed-out picture.

 

[zevrix]

I guess it's a bug in misinterpreting GIMP images then, as others already mentioned.

I can't reproduce the issue with 5000 px PNGs created in either Photoshop or Preview.

Still, I agree that it's a bug.

If you haven't done it yet, report it to Apple.

Also, if possible at all, you can contact GIMP developers and ask them to include their own QL plug-in (it can be embedded in the app itself). It might be a better chance than waiting for Apple to fix it.

 

[saldin]

I guess it's a bug in misinterpreting GIMP images then, as others already mentioned.

I can't reproduce the issue with 5000 px PNGs created in either Photoshop or Preview.

Still, I agree that it's a bug.

If you haven't done it yet, report it to Apple.

Also, if possible at all, you can contact GIMP developers and ask them to include their own QL plug-in (it can be embedded in the app itself). It might be a better chance than waiting for Apple to fix it.

I don't know why you can't reproduce the issue. I confirmed the issue with two different Macs with different configurations and installed software, and my friend's MacBook Pro M1 didn't even have GIMP (which rules out GIMP as a problem) and I could easily reproduce the problem on both. I even mentioned in comment #6 that for one test I skipped GIMP and used Preview to generate the images and got the same result.

I see this all the time because my Mac Mini is plugged in to a 1080p monitor, so I'm constantly searching image files and Quick Looking them, and text inside PNG high resolution screenshots is really blurry.

I've already reported this to Apple using their product feedback page (

Product Feedback

We would love to hear your comments about any of our hardware and software products. Send us your thoughts.

www.apple.com

) and their feedback assistant page (

Feedback Assistant

feedbackassistant.apple.com

) but it's been radio silence for months on end. If there are more ways to report this to Apple, let me know and I'll use them.

Here's another example that's more practical and probably easier to understand. This is a 6K image file (6144x3456) equivalent to a screenshot of a 6K screen, and how it looks when made to fit on my FHD monitor:

6K JPG image file, Quick Look and zoomed to approximately 100%. It's perfectly legible:

Same 6K image file, but PNG this time, Quick Look and zoomed to approximately 100%. It's blurry, and the higher resolution it is or the smaller the detail, the blurrier it is when zoomed:

 

[zevrix]

I don't know why it happens.

Here's a 5000x3000 PNG from Photoshop on my 4K 27" Dell monitor:

 

[zevrix]

...and at 100% (expected quality for an enlarged screenshot):

 

[saldin]

That dialog box alone seems to be 5000x3000. I don't think it would show the problem like that...

Can you try taking a screenshot of your desktop? It will generate a PNG file and export it to JPG (zero compression/highest quality). Quick Look both and zoom in to the Macintosh HD icon and name. Do both look the same quality? These examples come from the MacBook Pro M1 and the PNG screenshot is notably blurry:

 

[zevrix]

png:

jpg:

 

[saldin]

png:

View attachment 2433059

jpg:

View attachment 2433061

That's odd. They do look similar...

 

[saldin]

I was lucky to get ahold of a 13-inch MacBook Air M3 just now and did the same test. I could start noticing the blurring only after zooming in really really hard, and it's there alright:

JPG:

PNG:

I wonder if having a lower-DPI 1080p monitor makes this problem stand out more...

 

[zevrix]

I wonder if having a lower-DPI 1080p monitor makes this problem stand out more...

Yes, I do think you monitor is the most likely reason for this.

I don't see any "problem" in the hugely enlarged screenshots from your MacBook Air; JPG provides a slightly worse result, as would be expected in this case. But you can't expect any kind of acceptable quality after enlarging screenshots like this anyway.

 

[saldin]

Yes, I do think you monitor is the most likely reason for this.

I don't see any "problem" in the hugely enlarged screenshots from your MacBook Air; JPG provides a slightly worse result, as would be expected in this case. But you can't expect any kind of acceptable quality after enlarging screenshots like this anyway.

I agree that my 1080p monitor seems to aggravate the problem, but it is a problem when any bitmapped image is smoothed-out when zooming in to, and past, 100%. Sampling when less than 100% zoom is a necessity and it's not under discussion.

No matter what, there should be no sampling nor smoothing at all when zooming in to, and past, 100% on any bitmapped image.

 

[zevrix]

No matter what, there should be no sampling nor smoothing at all when zooming in on any bitmapped image.

When you zoom in on the same images in Preview, do you experience a different behavior?

 

[saldin]

When you zoom in on the same images in Preview, do you experience a different behavior?

I mentioned it in the first post. I've tested that Preview does not have any problems: the same image in different formats is displayed correctly when zoomed to and past 100%.

The only thing at fault is Quick Look, and there's really no substitute for it when I have to search in Spotlight and browse for a particular document.