Affinity Photo resize/stretch for patterns

[altieres]

Hi!

I mostly use Affinity Photo to make simple edits to scale screen captures or blur information, so I'm by no means an advanced user. I'm also coming from Photoshop, and my question is related to a quirk/difference between the two.

I often resize screen elements to fill parts of the image or to better fit other aspect ratios. This often requires me to copy/paste a vertical or horizontal pattern that has a single pixel (if there's more, they're all the same). In Photoshop, I just select the part I'd like to repeat and then stretch it. In Affinity Photo, this doesn't work. The pattern seems to be affected by anti-aliasing or some other artifact that causes it to become partially transparent/gradient as I stretch it.

Here is a demonstration, where I start with a 1x1297 layer and then stretch it horizontally. Photoshop just repeats the pixel and forms a pattern, but Affinity Photo seems to add anti-aliasing, breaking the repetition:

https://www.youtube.com/watch?v=Y-aoCjqCUow

I found two ways to do this in Affinity Photo:

1. With a Pattern layer. Creating a pattern layer from the selection works sometimes, but in this particular case (where I started with an empty document) it was not working. I didn't investigate much, but it usually achieves the intended effect on more real world scenarios.
2. With a Bitmap fill. If I export the pattern to a new file and then import it back as a bitmap fill in the gradient tool, it's possible to repeat it. This works every time, but it's not convenient.

The question I have is: are these two the optimal solutions, or am I missing something? Since I just had to stretch the layer in Photoshop, it felt like I was doing something wrong in Affinity Photo, and that there could be some keyboard shortcut or a toggle to do this.

I'd also like to understand why this difference exists. Perhaps it will help explain other quirks/differences between PS and Affinity.

Thanks.

Edited September 30, 2021 by altieres

[John Rostron]

Hello @altieres, and welcome to the forums.

You may be interested in this truck I discovered to expand a single column of pixels to fill the entire width of an image.

To expand the central column:

Filter >  Distort > Equations

Set x=w/2

Click OK

To expand any other column use x=a*w and use the a slider to adjust position.

To expand a row, use y=h/2 or y=a*h.

John

[altieres]

Hi, @John Rostron, thanks for your reply!

I was unfortunately unable to replicate your trick. Seems like it could be another solution to my use case.

Can you give some more details? For instance, do I have to select the column of pixels I want to stretch or create a new layer?

Also, do I leave "Extend mode" at Zero?

Kind regards,