[Upstream Bug, unfixable] Pixels on canvas are misaligned

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Re: [Blocker Bug] Selection border not aligned with pixel grid - Impossible to reliably tell which pixel selected

Post by forum_adm »

The scroll view magnification is not a solution. Because it zoom all elements and overlays.

But I added now some workarounds which may solve your issue.

1) Uncheck the option "Use cached scaled…"
2) Select for the interpolation the default one.

GraphicConverter uses now if the zoom factor is an integer like 1, 2, 3, … the default interpolation (which is none).
GraphicConverter uses now automatically the high quality interpolation setting if the zoom factor has a fraction.

The interpolations are NOT my algorithms. That interpolations are provided by Apple Core Image for the display of images.

Please report.
porg
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Re: [Blocker Bug] Selection border not aligned with pixel grid - Impossible to reliably tell which pixel selected

Post by porg »

Thanks for your reactions! In which beta version can I test these changes?
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Re: [Blocker Bug] Selection border not aligned with pixel grid - Impossible to reliably tell which pixel selected

Post by forum_adm »

5485
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Re: [Blocker Bug] Selection border not aligned with pixel grid - Impossible to reliably tell which pixel selected

Post by forum_adm »

Sorry, but the autocorrection changed a word wrong.

Correct is: not my algorithms - Apple provides them - I corrected the post.
porg
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Re: [Blocker Bug] Selection border not aligned with pixel grid - Impossible to reliably tell which pixel selected

Post by porg »

Before I could test all aspects of your answer I ran into another showstopper:

Pixel Grid Alignment - New Zoom and Interpolation in GC 11 build 5475 - Image opens with huge checkerboard canvas around.png
Pixel Grid Alignment - New Zoom and Interpolation in GC 11 build 5475 - Image opens with huge checkerboard canvas around.png (323.95 KiB) Viewed 234 times
porg
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Re: [Blocker Bug] Selection border not aligned with pixel grid - Impossible to reliably tell which pixel selected

Post by porg »

And sadly, the original problem persists: ❌ Selection still not aligned to pixel grid:


Pixel Grid Alignment - New Zoom and Interpolation in GC 11 build 5475 - Selection still not aligned to pixel grid.png
Pixel Grid Alignment - New Zoom and Interpolation in GC 11 build 5475 - Selection still not aligned to pixel grid.png (292.07 KiB) Viewed 232 times
porg
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Re: [Blocker Bug] Selection border not aligned with pixel grid - Impossible to reliably tell which pixel selected

Post by porg »

And in case you overread it: In order to reproduce the bug:
- Zoom in so close that you see blocky pixels
- At the beginning you may be lucky and the selection aligns perfectly to the pixel grid where you set the selection
- But drag a selection edge point horizontally for a while, and the offset accumulates, until you see it clearly
- The same is true is you drag it vertical, also then you will see the offset after a certain time

Can you reproduce this?
- Try differently sized images (odd/even pixels) with different resolutions (72 DPI, 144 DPI, …) on different DPI-displays (72 DPI, 144 DPI, …).
- If you are already on macOS 12 Monterrey necessary try on macOS 11 Bigs Sur
- I do not know what the preconditions are, you are the developer.
- But I sadly seem to get this in all images
porg
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See how the canvas not being aligned with the image content changes somehow proportionally with the zoom level using cmd

Post by porg »

Zoom 033.png
Zoom 033.png (41.8 KiB) Viewed 227 times
Zoom 066.png
Zoom 066.png (62.77 KiB) Viewed 227 times


At 100% it is OK again:


Zoom 100.png
Zoom 100.png (56.01 KiB) Viewed 227 times
Last edited by porg on Fri Apr 22, 2022 11:17 am, edited 1 time in total.
porg
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At 150% it is also correct: Canvas is not larger then image content, at all edges: top left, top right, bottom left, bot

Post by porg »

Zoom 150 a top left.png
Zoom 150 a top left.png (50.69 KiB) Viewed 225 times
Zoom 150 b top right.png
Zoom 150 b top right.png (41.8 KiB) Viewed 225 times
Zoom 150 c bottom right.png
Zoom 150 c bottom right.png (41.78 KiB) Viewed 225 times
Last edited by porg on Fri Apr 22, 2022 11:17 am, edited 1 time in total.
porg
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Post by porg »

Zoom 150 d bottom left.png
Zoom 150 d bottom left.png (48.41 KiB) Viewed 225 times