Interpolation in select tool.

[amoraleite]

Guys I don't locate this essencial feature. 

How can I change the interpolation method from a layer selected in Affinity Photo?  I know, I can do this in the entire document... But if I select a simple part or a layer, can I do this too? Change the interpolation? 

 

 

Thank you! 

[walt.farrell]

Can you explain more about what you mean?

[amoraleite]

Thank you all for your answers. Let me provide a clearer explanation. In applications like Photoshop, ArtStudio Pro or Procreate, I have the ability to individually select the interpolation mode for each layer when resizing. Suppose I have 5 layers and I need to resize them. In the mentioned programs, I can choose the desired interpolation method for each layer. Generally, I prefer using bicubic interpolation, but in cases where I require precise pixel art, the nearest interpolation method is the most suitable. One suggestion is: with the select tool, I can easily access a dialog that allows me to choose the interpolation method I want to use for each layer the I selected. 
 

what do you think guys? 

[v_kyr]

See and note what is only available there and that there's nothing like that for layer selections ...

• APh 2 Online Help
• Selections
  • Creating pixel selections
    • Overview
    • By painting
    • By flooding
    • By drawing
    • By range
    • By layer content/luminosity
    • From channels
    • From layers  <--- ***
    • From shapes
    • From a sampled colour
    • Using a marquee
  • Modifying pixel selections
  • Moving and transforming pixel selections
  • Edit selection as layer using Quick Mask
  • Refining pixel selection edges
  • Creating outline selections
  • Saving and loading selections

[amoraleite]

17 minutes ago, v_kyr said:

See and note what is only available there and that there's nothing like that for layer selections ….

Yes you right! There’s nothing like that. Suggestion for an update? 

[v_kyr]

2 minutes ago, amoraleite said:

Yes you right! There’s nothing like that. Suggestion for an update? 

If you think that it is an essential missing feature, then you can make a suggestion here ...

• Feedback & Suggestions ...
  
  -->   https://forum.affinity.serif.com/index.php?/forum/122-feedback-for-the-affinity-v2-suite-of-products/

[amoraleite]

I’ll. 
 

another post with same requesting:

 

 

[amoraleite]

That’s it @Red Sands

❤️ 

Gimp has this feature too: 

 

[lacerto]

Photoshop has had this feature at least since CS6. It can be applied selection-wise differently within a same layer.

[NotMyFault]

For clarification: what is called interpolation in other apps is called resample method in Affinity Apps.

• You have a wide choice of resample methods, but only during export or resize (of whole document)
• you can choose between bilinear and nearest neighbor for canvas rendering, but it is independent from resizing, export, merge/rasterize etc.
• you cannot influence the resample method used for rasterize / flatten / merge operations for individual layers while editing (Not exporting). It is always bilinear. For details, see 

[amoraleite]

Sad news guys... This feature is very very common in other apps of photo editing.  😔

And this workaround is painful: ( If you want to scale individual layers using a different resample method, you need to copy/paste it into a new temporary document, Resize / Resample the temporary document, and copy/paste the result back into the original document.).

Of course, people use this app for different objectives, and if you have two or three layer is ok, but if you do a big composition you will have a lot of layers, and this type of control is crucial for accuracy and this workaround is madness. 

Do you know or hear if the staff plan to fix this missing feature? In my opinion this can't be a new feature this would be a fix. Is basic. 

Thanks 
@lacerto @NotMyFault

[lacerto]

8 hours ago, amoraleite said:

And this workaround is painful: ( If you want to scale individual layers using a different resample method, you need to copy/paste it into a new temporary document, Resize / Resample the temporary document, and copy/paste the result back into the original document.).

If it only were that "simple". E.g., whenever pixels really need to be interpolated/resampled (and not just duplicated), bilinear sampling (blurred edges) will result even when using "Nearest Neighbor" as the algorithm. Just compare the difference between PS based nearest neighbor based interpolated transformation of selected pixels vs. doing the same via document resize in Photo:

 

 

There was a recent 10-page discussion on reasons why this happens:

Note that on canvas (without document resampling), blurred (antialiased) edges occur even when resizing (enlargening a pixel selection) by duplicating pixels but just in width or height -- only perfect scaling (multiplying by factor of 2, 3 etc. both the width and height) of a rectangle shape selection of solid RGB black pixels produces unblurred (non-antialiased) edges.

[NotMyFault]

@lacerto why do you resample to 12.8px size? Timecode 1:20 in your video. It does not make sense to use fractional document sizes, probably you know. PS probably automatically rounds to whole pixels, a step which needs to be done manually in Photo.

[NotMyFault]

1 hour ago, lacerto said:

Note that on canvas (without document resampling), blurred (antialiased) edges occur even when resizing (enlargening a pixel selection) by duplicating pixels but just in width or height -- only perfect scaling (multiplying by factor of 2, 3 etc. both the width and height) of a rectangle shape selection of solid RGB black pixels produces unblurred (non-antialiased) edges.

Yes, by chance yesterday I stumbled (again) over this issue. It only happens for certain aspect ratios and factors. If you scale e.g. by 2x / 3x no extra blur occurs, but if you scale by 1x / 3x it does. When using larger scale factors (above 2.0), anti-aliasing at edges effectively breaks down.

[lacerto]

On 6/2/2023 at 9:29 AM, NotMyFault said:

@lacerto why do you resample to 12.8px size? Timecode 1:20 in your video. It does not make sense to use fractional document sizes, probably you know.

Affinity apps do round up that to 13px [EDIT: they do not, but behavior is most often identical whenever scaling is not uniform], and it does not matter at all whether I uncheck the aspect ratio lock and manually enter the value to 13. The point is, if the scaling is not duplicative (and integral), Affinity apps will apply antialiasing on edges, even when using Nearest Neighbor resampling algorithm. In Photoshop Nearest Neighbor does what it promises, stays hard-edged, no matter how the image is distorted, whether when resizing pixel selection, or resampling a document.

It is not just Nearest Neighbor that In Affinity apps works badly, as regards edge handling. Edge antialiasing is absurdly bad also when using other resampling algorithms, it is kind of feathering without asking for any (as if having initially used either feathering or antialiasing when selecting pixels).

Example: 3x2px resampled to 500x20px using Bilinear algorithm in Affinity Photo 2:

The same thing done in Photoshop 2023:

I am not sure what you mean by saying that "antialiasing breaks down when using large scale factors". Here the image has been scaled up at factor of > 5, to 4,000x1,444 (manually rounding up height to nearest integer, though as mentioned, this is trivial as the app does edge antialiasing anyway):

Antialiasing is as bad as ever, but if you mean that it is insignificant in larger sizes because of viewing distances are typically bigger then of course that is true. But hard-edged resampling is very important when working with small bitmaps, and it should naturally operate flawlessly, both on canvas and especially when resampling.

[NotMyFault]

2 hours ago, lacerto said:

I am not sure what you mean by saying that "antialiasing breaks down when using large scale factors".

Take a checkered square of 32x32px.

stretch it to 64x32. The left/right side gets anti-aliased (1px semi-transparency)

stretch it to 128x32. The left/right side gets anti-aliased (2px semi-transparency)

now begin to stretch on y-axis to 48px, then 49px. Edge anti-aliasing stops working completely (only alpha channel is active in channels panel)

Edited June 2, 2023 by NotMyFault
typo (thanks Alfred)

[Alfred]

8 minutes ago, NotMyFault said:

Take a checkered square of 32x33px.

Typo alert! You obviously meant to write “32x32px”.

 

[lacerto]

35 minutes ago, NotMyFault said:

Edge anti-aliasing stops working completely (only alpha channel is active in channels panel)

Are you suggesting that this is the method to get hard-edge nearest neighbor resampling in Affinity apps? Or are you saying that any antialiasing (also when one is wanted) "breaks" (stops from working) at certain point?

[NotMyFault]

4 hours ago, lacerto said:

Are you suggesting that this is the method to get hard-edge nearest neighbor resampling in Affinity apps? Or are you saying that any antialiasing (also when one is wanted) "breaks" (stops from working) at certain point?

Both. 

• It is a bug (or known limitation) that edge initialising works only with scale factors up to 2x
• This bug could be "misused" to avoid anti-aliasing in certain cases. But it would not fix the blurring inside the layer.
• Update: you inspired me to create a tutorial based on this trick.
•  
• Most people see the edge antialiasing in case of widely stretched pixel layers as unwanted. (side node: if you really need it, use motion blur insted)
  Bonus bug: even if you deactivate anti-aliasing in blend range for a layer, rasterise ignores this 

[lacerto]

16 hours ago, NotMyFault said:

It is a bug (or known limitation) that edge initialising works only with scale factors up to 2x

I am not sure what you mean? With certain specific situation or algorithm? In my example where I applied over 5 time (almost) uniform scaling, the unwanted antialiasing is still clearly seen. And it is certainly still applied in the 3x2px bilinear sampling which gets stretched to 500 x 20 (appr. 167x horizontally and 10x vertically). Unless I misunderstood something it would seem that these workarounds are very specific. 

16 hours ago, NotMyFault said:

Bonus bug: even if you deactivate anti-aliasing in blend range for a layer, rasterise ignores this 

Aren't blend range based antialiasing settings only applicable on vector shapes / text? On the other hand, when exporting to e.g. PNG, I can force nearest neighbor as resampling method but that would then also leave layers where antialiasing is wanted (e.g. text) hard edged. "Interpolation" should ideally be very specifically and locally appliable. 

[NotMyFault]

1 hour ago, lacerto said:

I am not sure what you mean? With certain specific situation or algorithm?

Only for in-document rendering (using bilinear). I did not yet check what happens during export.

 

Aren't blend range based antialiasing settings only applicable on vector shapes / text?

Yes, normally I use rasterise on vector objects.

 

[amoraleite]

@lacerto thank you for your detailed exemples. That’s it. 
 

Many others softwares ( from Gimp, Krita etc…) I've tested have this basic feature. I opened a suggestion in the appropriate place. Some people do not understand what this is and what it is for. I understand. But if you don't use it or don't know what it's for, please don't question it because we need it. And it's already pretty clear to me that it's something that APhoto doesn't have. We need the production team to see this and propose how to fix this basic feature. Now, after purchasing the entire Serif package, I'm using another image editing app to do what I need. But I wanted to put it on record, I love how serif programs are turning out, I love ADesigner. I invite you to visit my website, I have been an illustrator for a long time, www.amoraleite.com here in this forum I just arrived, and I only have this request for the Serif team, for now… 🙂

[amoraleite]

@Serif_Desktop @Serif Info Bot guys there any way to mark the production team? 

[v_kyr]

23 minutes ago, amoraleite said:

guys there any way to mark the production team?

You shouldn't mark them, instead as I've already told before (see above) make a

• Feedback & Suggestions ...

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[NotMyFault]

I just created a mini tutorial to show how you can avoid blurriness in the special case of scaling pixel art by integer multiples (can be different for x and y axis).

If link does not work, wait 15 minutes (until it receives moderator approval).