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metallissimus
Experienced
Topic Author
Posts: 68
Joined: 17 Oct 2019, 06:54

Image quality after zoom in popup

07 Oct 2020, 07:48

Hey there,

I just uploaded some pictures (via FTP) for a client to select from and for the first time activated the zoom button in the popup.
The zoomed in image looks terrible, like heavily compressed or blown up from a smaller version. How can I prevent this?
Bildschirmfoto 2020-10-07 um 13.42.30.jpg
Original file vs. popup
Bildschirmfoto 2020-10-07 um 13.42.30.jpg (404.44 KiB) Viewed 75 times
 
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mjau-mjau
X3 Wizard
Posts: 12293
Joined: 30 Sep 2006, 03:37

Re: Image quality after zoom in popup

08 Oct 2020, 00:10

You mean the image looks terrible after you click the zoom button? When you click the zoom, it will load the ORIGINAL image (unaffected by X3), in which case you are seeing an image with a color profile that is not properly supported in your browser. In your screenshot, you have Mac preview app vs browser, in which case the Mac preview app supports your local color profile, whereas browsers need to support/adjust colors for a global audience.

This is the original image, unaffected by X3, which is displaying when you click zoom:
https://www.danielbollinger.de/content/ ... au-003.jpg

This is a downsized version by X3:
https://www.danielbollinger.de/render/w ... au-003.jpg

There is a slight difference in colors of the two, although in your case, it sounds like you don't like the ORIGINAL version (when displaying in browser). For your info, your original image is RGB IEC61966-2.1, which I believe is an Adobe-specific color profile variation. You should probably convert to sRGB before publishing photos to the web ... Optionally, you can enable "copy color profiles" for the X3 resizer, but that would only mean that resized images would look identical (in terms of colors) as the original ... It would not help browsers display colors "correctly" if the profile is not properly supported bro browser, and that's why you should probably convert to sRGB. See this post:
https://om4.com.au/client/preparing-ima ... adobe-rgb/
 
metallissimus
Experienced
Topic Author
Posts: 68
Joined: 17 Oct 2019, 06:54

Re: Image quality after zoom in popup

08 Oct 2020, 14:04

mjau-mjau wrote: You mean the image looks terrible after you click the zoom button? When you click the zoom, it will load the ORIGINAL image (unaffected by X3)
Yes, I do, and no, this doesn't seem to work in this case. My screenshot shows the image in Mac preview and on my website AFTER clicking the zoom button, so there should be no difference at all. If I compare the original on my website (via the link you posted) with my local original, there is indeed no visible difference.
For your info, your original image is RGB IEC61966-2.1, which I believe is an Adobe-specific color profile variation.
That's also strange, because my local file says "sRGB IEC61966-2.1" (as reported by finder file info).
 
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mjau-mjau
X3 Wizard
Posts: 12293
Joined: 30 Sep 2006, 03:37

Re: Image quality after zoom in popup

08 Oct 2020, 23:55

metallissimus wrote:Yes, I do, and no, this doesn't seem to work in this case. My screenshot shows the image in Mac preview and on my website AFTER clicking the zoom button, so there should be no difference at all. If I compare the original on my website (via the link you posted) with my local original, there is indeed no visible difference.
A bit unsure what you are claiming above. Mac preview will support all color profiles, especially local on your own Mac, so you can't use that as comparison. As long as you are getting a difference between the WEB and your Preview app, regardless of HOW it happens, clearly it's a color profile issue you must agree.

As for the popup, I'm not quite sure what you are seeing from your screen. Here are the only possibilities: 1) In 95% (or more) of cases, the original source image is already loaded into the X3 popup, especially if viewing from a desktop screen (1280+) ... X3 will only load a smaller image in very few cases where the screen res is MUCH lower than the original image res. So if the original is loaded, and you click ZOOM, it can't possibly load a different/larger image ... It's the same. 2. In the rare case that a smaller image is served, then when you click ZOOM it will definitely load the original upload.

In conclusion, regardless of serving resized or not, it would always display the original upload after zoom (even if it's the same image). You can check this in browser network inspector. Click "images" tab, then open the popup, then click "zoom", and see what images load.

In the end, X3 cannot and does not change colors of original uploaded images ... How can it? It loaded it into browser, and this image can't look different in X3 than when the image is loaded separately in browser. This is a problem of color profiles vs browser support for color profiles ...

3. Another option worth mentioning, but that does not seem to match what you are experiencing: It could be resized images have not copied your specific color profile, in which case they could look different (especially in browser). However, in this case, the original (after clicking zoom) would be your original naturally, and the initial pre-zoom should be "wrong". This doesn't seem to match your case.

4. There is an unlikely scenario that some network or your ISP is performing some optimization on images.
metallissimus wrote:
For your info, your original image is RGB IEC61966-2.1, which I believe is an Adobe-specific color profile variation.
That's also strange, because my local file says "sRGB IEC61966-2.1" (as reported by finder file info).
[/quote]
Yes sRGB IEC61966-2.1. Point is, it is an Adobe-specific color profile. Almost certainly related to the issue.

I suggest you check network inspector and see what images load.
 
metallissimus
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Posts: 68
Joined: 17 Oct 2019, 06:54

Re: Image quality after zoom in popup

09 Oct 2020, 06:36

mjau-mjau wrote: A bit unsure what you are claiming above.
I made another comparison to make it clearer and show that it's not related to Mac preview vs. browser: The following screenshot shows the image accessed directly in the browser (on the left) and the image after clicking zoom in the popup (on the right). The difference in sharpness remains the same as in my previous screenshot.
Bildschirmfoto 2020-10-09 um 12.22.55.jpg
Bildschirmfoto 2020-10-09 um 12.22.55.jpg (521.61 KiB) Viewed 53 times
I suggest you check network inspector and see what images load.
If I interpret this correctly, the original image is loaded. But why is it not sharp?
Bildschirmfoto 2020-10-09 um 12.30.32.jpg
Bildschirmfoto 2020-10-09 um 12.30.32.jpg (794.44 KiB) Viewed 53 times
Yes sRGB IEC61966-2.1. Point is, it is an Adobe-specific color profile. Almost certainly related to the issue.
Sorry, I was so focused on the "s", that I didn't look at the numbers because you said I should convert to sRGB and I was sure that I already exported sRGB. But I think my screenshot above with comparison directly in the browser shows that the sharpness issue isn't related to this.
 
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mjau-mjau
X3 Wizard
Posts: 12293
Joined: 30 Sep 2006, 03:37

Re: Image quality after zoom in popup

09 Oct 2020, 06:59

Do you have a public link for me so I can study it a bit further? I believe you removed that folder, or added password protection? What about other images in other galleries? The same happens?
 
metallissimus
Experienced
Topic Author
Posts: 68
Joined: 17 Oct 2019, 06:54

Re: Image quality after zoom in popup

09 Oct 2020, 07:44

Here's a little test folder I set up and I could narrow it down a little: It seems like the problem only affects images in portrait orientation, not landscape. https://www.danielbollinger.de/popup-test/

The problem exists in Firefox 78.3.1esr (64-Bit) as well as in Safari Version 12.1.2 (which might be outdated, I just wanted to do a quick test with a different browser) on OS X 10.14.6.
 
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mjau-mjau
X3 Wizard
Posts: 12293
Joined: 30 Sep 2006, 03:37

Re: Image quality after zoom in popup

09 Oct 2020, 22:50

I managed to recreate the issue, and have located a bug. In short:

X3 will initially load an image size into the popup that satisfies the screen pixel resolution. In most cases, this is often the original image, especially when you click to view a landscape image from a landscape-aspect desktop screen. That is why, when you click to zoom a landscape image, the original image is already loaded and will simply zoom in to original pixel resolution.

However, when clicking a portrait image, X3 will sometimes load a smaller image. Example, my screen is 1280 x 800 retina, effectively 2560 x 1600 pixels. The vertical space available in browser is likely more like 1400 px (browser UI). Your original image is 1920 px tall, which is basically overkill in non-zoom view.
https://www.danielbollinger.de/content/popup-test/Popup-003.jpg

X3 therefore serves a downsized version 1024 x 1536 px, which is more than sufficient in non-zoom view. The 1536 px height more than satisfy the 1400 px screen height. With this, it only loads 400kb (resized) instead of 1.2mb (original). This is quite elementary.
https://www.danielbollinger.de/render/w ... up-003.jpg

However, when a downsized version is served in initial view, it should be serving the original after you click zoom. This is what happens when I initially click the image. As you can see, it has correctly loaded the w1024 (1536 px height) version. The w800 version is actually from the gallery layout, and also acts as a "preload" for the popup (while waiting for the large image to load).
Image

This is what happens when I click zoom. It correctly loads the original image. However, there is a bug where the original image fails to actually replace the image in popup after it's loaded. The downsized w1024 px version is still displaying. So while you have zoomed in and the popup thinks it's displaying the original, it is in fact still displaying the w1024 px version. Bug!
Image

I am currently working on a new X3 popup design, and should have this issue fixed with the new release within 1-2 weeks. Thanks for bringing this to my attention!
 
metallissimus
Experienced
Topic Author
Posts: 68
Joined: 17 Oct 2019, 06:54

Re: Image quality after zoom in popup

13 Oct 2020, 06:34

mjau-mjau wrote: Thanks for bringing this to my attention!
I'm very glad if I can in a way give something back in return for your great support.