Snapping does perfectly snap 2 objects

[Phoxsty]

I have noticed that many times when I have multiple objects close to each other they seem to have a small gap when I zoom out. I just now zoomed all the way in and there appears to be a gap. This occurs both when I have the "Move by whole pixel" enabled and disabled in the snapping tool.

Here you can see a small gap when I am zoomed out and when zooming really really close you can see the gap be there clearer .

Does anyone know why this issue occurs and how to set up the settings to eliminate it. I know the issue goes away when I export the image since the gap is less than a pixel wide but it is annoying not being able to preview your picture without exporting it.

 

Edited December 2, 2023 by Phoxsty

[loukash]

Although it may seem counterintuitive, make sure that "Move By Whole Pixels" is disabled and "Force Pixel Alignment" is enabled.
Also make sure that you have activated 6 decimal places for pixels in the User Interface preferences. Then double check using the Transform panel that all items on your canvas are aligned to integer pixel values and have integer pixel dimensions.

[Phoxsty]

I had the Move by whole pixel disabled at first and Force Pixel Alignment has always been enabled for this document. I changed the decimal setting for both Point and Pixels to be safe. Going over both the elements and their respective parent every value in the Transform panel shows only whole numbers without decimals but the gap still shows. Especially when I am zoomed out to view my full 1920x1080 canvas. Is there something else I need to check in the transform panel to enforce only integer value?

This time I saved/exported the image to a PNG the gap actually showed up. Something I've not seen before.

Edited December 2, 2023 by Phoxsty

[Phoxsty]

I might have found the problem myself. The issue does not revolve around the snapping the issue comes from scaling an object up. As you can see in the attached image #1 the outline showing your current selection has a small gap. This is a 16x16 pixel texture that has been scaled up to become 102x102 pixels which is 6.375 times larger. Sadly scaling the object to 112x112 pixels instead (which is divisible by 16) you still get this issue where the selection does not line up with the actual texture.

Seeing attachment 2 and 3 you there problem seems to only be on the left and top while being perfectly aligned bottom and right side.

Image 1

Image 2

Image 3

[loukash]

When you're working in such tiny dimensions, everything simply must be aligned to the "absolute" document pixel grid to prevent unwanted antialiasing.
Also, make sure to enable the pixel grid, or create a custom grid based on pixels.
Also enable View → View Mode → Pixels to see a preview based on your document DPI.

There's also a still unresolved bug with artboards:
If you have multiple artboards, then the absolute document pixel grid starts at the top left-hand corner of the top left-hand artboard on the canvas.
Any other artboards on the canvas must be then also aligned to integer pixels values counting from that absolute X,Y = 0 px.
The bug is that each artboard seemingly claims its own pixel grid based on its own ruler values, even though the absolute canvas position of the artboard is non-integer. That may lead to antialiasing on export although in theory there shouldn't be any. 
You can check the absolute artboard position in the Transform panel if you select the Artboard object with the Move tool.
Also the Pixel Preview will show antialiasing of seemingly aligned objects if a "secondary" artboard isn't on the absolute pixel grid.

Those issues often don't matter much when working for print at 300 ppi, but if you're a "pixel pusher", then great care needs to be taken.

Edited December 2, 2023 by loukash
see below

[loukash]

13 minutes ago, loukash said:

If you have multiple artboards, then the absolute document pixel grid starts at the top left-hand corner of the top left-hand artboard on the canvas.
Any other artboards on the canvas must be then also aligned to integer pixels values counting from that absolute X,Y = 0 px.

^ Actually I just noticed that it's not exactly like that.

The "absolute pixel grid" is not fix:
X=0 is where the left border of the left-most artboard begins.
Y=0 begins where the top border of the top-most artboard begins.
If you move Artboard2 so that its top border is above top border of Artboard1 with Force Pixel Alignment disabled, resulting, in non-integer pixel movement, you will "push" the previously nicely aligned Artboard1 off the absolute grid.

It's maddening sometimes…  

[Phoxsty]

34 minutes ago, loukash said:

Also, make sure to enable the pixel grid, or create a custom grid based on pixels.
Also enable View → View Mode → Pixels to see a preview based on your document DPI.

I already have pixel grid enabled and due to the scaling that I didn't get quite right the pixels don't perfectly align. But when I place an object that is perfectly aligned with the pixel grid and no other oddities are occurring I still see that the selection outline does not line up with my texture unless I enable the pixel view mode. This becomes a great issue when working with more complex vectors than just squares because using pixel mode will not work there. Here I can get by since I am working with rectangles.

Also I only use 1 artboard.

[loukash]

Perhaps you may want to upload an example document so that someone can look at it.

[Callum]

Hi @Phoxsty,

If you could provide a sample file as Loukash requested we should be able to get to the bottom of this with you.

Thanks
C

[Phoxsty]

Sorry for a late reply. Have been quite sick the last week so not been on my computer much. I made a document showing of the problem I found. It has both the issue itself and a screenshot in the same document.

example.afdesign

[loukash]

1 hour ago, Phoxsty said:

I made a document showing of the problem I found. It has both the issue itself and a screenshot in the same document.

The green "Background" rectangle is a pixel object. Is there any specific reason why you're not using a vector shape?

[Phoxsty]

In this case the reason is only to show the issue. When I originally found the issue it was because I was using a texture map and just wanted to lay out multiple copies of the same texture.

[Phoxsty]

You can see the same thing happen when I place an SVG though so it doesn't seem to be a problem only with pixel objects.

Here is the same SVG in Designer and Illustrator.

Left => Affinity Designer 2 | Right => Illustrator 2023

[loukash]

I don't see any issue in your document. The green "pixel" type rectangle is integer pixel size and alignment, and it exports crisp. The document appearance itself is as expected.

As for the SVG, I see what you mean but I can't tell more without inspecting it, or a similar example.

[Phoxsty]

1 hour ago, loukash said:

I don't see any issue in your document.

The problem is that the blue outline of the selected element is not exactly on the pasted object. I understand the difference between pixel and vector but even when placing a pixel object in a vector space you should still confine the selection to the object. The document is set up to all the based on pixels so if all values are integer the outline should not have a small gap to the actual pixel object placed. This is what is causing the small gap between 2 elements and making the background shine through. I assume the same is happening with the SVG.

I attached an SVG with only the background of what I was working on.

example.svg

[Old Bruce]

11 minutes ago, Phoxsty said:

The problem is ....

Your example.svg is made of vector objects which are not pixel aligned, nor are they sized as integer pixels  for height and width.

 

[loukash]

20 minutes ago, Phoxsty said:

the blue outline of the selected element is not exactly on the pasted object

I can see it on your screenshot, but there is no such issue in your file when opened on my setup. The green pixel rectangle bounding box aligns perfectly, including the Export persona.

26 minutes ago, Phoxsty said:

VG with only the background of what I was working on

15 minutes ago, Old Bruce said:

Your example.svg is made of vector objects which are not pixel aligned, nor are they sized as integer pixels for height and width.

Exactly. This will be even more obvious if you consequently work in the Pixel Preview mode.

[Phoxsty]

40 minutes ago, loukash said:

The green pixel rectangle bounding box aligns perfectly, including the Export persona.

Wait so for you the blue outline showing the selection lines up with the green box even when zoomed very far in?

Because when I am zoomed out it looks quite normal to me too but when I zoom in to like 1 million percent I can clearly see they are not aligned.

[Old Bruce]

5 minutes ago, Phoxsty said:

when I zoom in to like 1 million percent I can clearly see they are not aligned.

To be blunt: Then you have no problem.

[Phoxsty]

24 minutes ago, Old Bruce said:

To be blunt: Then you have no problem.

To be professional: Yes I do. Because when you export the image you still get the artifacts. I had to place a solid coloured uniform object behind all the others to not get a 1 pixel wide gap.

I don't know about you but I care about this software and want it to improve. Excuses like that does not help.

[loukash]

52 minutes ago, Phoxsty said:

when I zoom in to like 1 million percent I can clearly see they are not aligned

When you "zoom in like 1 million percent" then a bed bug will eat you and your pets and your car and your house and it still will be hungry…  

Speaking of which: Yeah, all I can see is that rounding errors will start to propagate when I zoom in at about 20,000,000 %.
Meh.
How many design apps out there can even zoom that close? As far as I'm aware, none of those apps whose parent company name rhymes with Schmadobe.

[Phoxsty]

Probably not that many but they also don't have the issue when exporting to a png that Designer 2 has.

[loukash]

Fair enough, I agree that some Affinity workflows are not exactly intuitive, some I'd consider conceptually flawed, and some even have serious bugs.
Pixel alignment in Affinity also does have its issues, but in this very case none of them apply as far as I can tell from your examples.

Flexibility does have its price: A user must learn to understand all the options they have at hand.
In other words, if someone wants pixel fractions, they can have them. If you want to avoid them, then you must know how to work with integer values.