[Upstream Bug, unfixable] Pixels on canvas are misaligned

[porg]

In addition to the canvas being larger than the image content below 100% zoom, also the selection goes haywire during zooming in and out:

Watch video (21sec, 960 × 514, 300kB, Dropbox)
Or see this still frame story (hint) created with Graphic Converter's Collage Editor:

Selection gets offset when zooming in or out.jpg (249.1 KiB) Viewed 696 times

[porg]

11.6.1 (5486): Tested zooming again

These intermediary bugs that I reported, are meanwhile gone:

Canvas not being aligned with the image content changes somehow proportionally with the zoom level using CMD — +/-

Selection gets offset too when zooming in or out


Sadly the original problem still persists:

Selection border not aligned with pixel grid

[forum_adm]

I rechecked here on three machines and can't reproduce the alignment issue.

So, please email your exported GraphicConverter prefs for testing to support@lemkesoft.de

Screen Shot 2022-04-26 at 08.31.23.jpg (42.67 KiB) Viewed 685 times

[porg]

Just sent you the preferences via email.

[porg]

GC build 5488, also after a preference reset:
- This bug still reproduces.
- Both on my MBP 15.4'' Retina display and the external standard resolution 24'' display.

Sent you an email with porg-Preferences-GC-5488-20220426-1216-after-reset-only-changed-prefs-where-GC-prompted-me.xml

I send you the preference file as it is now.
Because maybe GC creates some settings during runtime (possibly config dependent).

The only preference I knowingly changed was when GC asked me how to deal with zoom when dealing with a Retina display.
General > Display Content > Default Zoom:
I set this to: Fill screen, shrink or expand to fit.

Other than that I did not customize anything. And still get the bug.

[porg]

The misalignment of pixels is also noticeable when the ruler shows single pixels.
Then you see only every n-th pixel is really aligned with the pixel units on the ruler.

Pixel Grid Misalignment also noticible when rulers show single pixel untis.png (79.34 KiB) Viewed 654 times

[porg]

I soo much would like to use GC more often!
But until that basic function works it is significantly less practical.

Anything left that I can do test-wise to help finding the root cause of this severe bug?
Do you already have some suspicions which you follow?

[forum_adm]

I can't reproduce the issue on Monterey. The complete image rendering is done by the macOS by the CGContextDrawImage call.

So, maybe an issue in your macOS.
Which macOS do you use?

[porg]

Environment

• Graphic Converter 11.6.1
• macOS 11.6.5 Big Sur (when initially reported, meanwhile 11.6.6, same issue)
• PNG of normal resolution (72dpi aka @1x)
• On a normal resolution screen.

[porg]

And let's try a bit more than "I can't reproduce". You know your app. You may have some suspicions, ideas, etc.
Maybe tell me some preferences which are involved in the metrics of rendering an image, which I shall try to tweak.
I have the suspicion that maybe General > Display Content > Editor Windows > may be misconfigured (even though being the defaults)

Maybe tweaking "PPI of Monitor" could fix it? Maybe the OS reports the resolution wrong?
See the specs of my internal and external display in my initial post(s).
Maybe we need to tweak the numbers to get the resolution correct and in consequence the software pixel grid to align onto the real physical pixel grid correctly. Because somewhere in the chain there seems to be a mismatch.

All my other graphics editing/viewing apps (Preview.app, Snagit both v2021 and v2022, Phoenix Slides, qView, Apple iWorks Suite) on the very same machine, which likely use the same drawing technologies underneath, don't have that issue. They are pixel precise.