BeauRX

Interesting but given what I have seen the focus is on much more core/central/infrastructure features, so I think unlikely especially given a relatively small team. I believe there are references on the forum to others using G'MIC as a plug in on Win so that might work. 

The perspective tool is far to clumsy in certain use cases.
often I want to correct a skewed image with help of a known rectangular object.
all I want to do
source mode: mark the 4 corners of a known rectangular area (which is perspectively distorted) switch to destination mode Photo creates a default perspective layer based on minimum or maximum of corner positions  Photo shows the result i can adjust the edges in dest mode to taste to correct overall aspect ratio affinity shows the size (in pixel and selectable measurement units) and aspect ratio of the resulting area in info panel while I adjust  

Hi,
 
there are multiple inconsistencies or bugs when dealing with adjustment layers impacting the alpha channel.
Nested adjustment layers on alpha in clipping position - digital alpha
When nested to "clipping" position of a curve layer,  vector shape, or group, adjustments will work only "digitally". There are 3 variants (curve, levels, channel mixer) to invert the alpha channel. They work correct if applied on top level. They work only for alpha = 1.0 when nested to clipping position. This seems to be similar to how stacks work, which reduce alpha to "digital" 0 / 1.  Nested adjustment layers on alpha in masking position - not getting clipped
Mask layers (and RGB part of all layer types) are getting restricted to the parent layer shape. Adjustment layers in nested masking position impact the overall canvas and don't get clipped to the group or curve shape. Nested adjustment layers on alpha in masking position - erratic alpha when zooming
Once you have an adjustment layer in clipping position, and zoom in or out, rendering gets erratic. The area outside the parent shape is rendered randomly in transparent or black or actual content depending on zoom level   
I reported some of these issues several month ago on Beta versions and Windows and iPad, unfortunately some reports did not get attention of moderators, and none got fixed. Since I now work on Mac and found the same old bugs on this OS platform, I want to ensure that all bugs are recognised by Affinity and hopefully get fixed.
Bugs affect Mac, iPad, Windows.
Bugs affect curves, levels and channel mixer adjustment who are specifically intended to work on alpha channel, documented in help and in official tutorials.
Bug affects all kinds of suitable parent layer types, e.g. group layers, curves, vector shapes. I'm sure Designer and Publisher layer types like picture frames, artboards, layer layers will be impacted, too.
PS: Just tested, Designer has 100% identical issues.
Bugs open since about 1.9.1 and still unfixed in 1.10.5 as of April 2022.
Why does this matter?
Currently since over 1 year it is absolutely impossible to use adjustment layers impacting alpha channel in combination with groups or any other kind or "structuring" with nested layers. This has become to a major obstacle where Photo (and Designer) looses core functionality for more complex than single - level layer stack documents.
Screenshots of test images.
Test setup before.
You see a rectangle with a gradient of skin tone (Hue 20) from black to max brightness, from left to right  A Mask gradient from  white to black in y-axis (top-down) A rectangle in 50% grey full opacity Several adjustment layers which invert either RGB or A, in clipping or masking position. Some got a diagonal stroke of erase brush to give them another level of complexity. PS:
The Issue no 1 "digital alpha" issues happens with parent layers of type vector, and groups with default blend mode "passthrough". The Issue no 2  and 3 (alpha not getting clipped, erratic rendering while zooming) happens in any tested case, including groups with blend mode "normal"  

1. Nested adjustment layers on alpha in clipping position - digital alpha
If you activate an A invert adjustment, only fully opaque pixels get A inverted.

 
2. Nested adjustment layers on alpha in masking position - not getting clipped

3. Nested adjustment layers on alpha in masking position - erratic alpha when zooming
Zoom 90%

Zoom 100%

FIN
nested alpha again V2.afphoto

Hi,
can someone explain if there is any written documentation / definition how group layers impact the alpha blend formula.
lets start with 2 innocent circles, having 50% opacity:

When using channels panel to show alpha, you see the areas of 0%, 50%, and 75% opacity

Adding an adjustment layer on top (posterise) or gaussian blur filter has no or limited effect on alpha.
 
When you put the adjustment into a group, this changes:
Now the result is a drastic impact on alpha channel, the well known alpha blend formula gets applied 
As an example, the over operator can be accomplished by applying the following formula to each pixel:
https://en.wikipedia.org/wiki/Alpha_compositing

 
What I do not understand is the different treatment of adjustment layers.
when nested or put above an layer, the alpha blend formula does not apply (to alpha channel). The result is simply using the alpha of the lower layer: α0 = αb When put in a group, the alpha blend formula applies: α0 = αa + (1-αa)*αb To generalise the question:
Is there any documentation which gives a full overview which rules apply to alpha blending, depending on different layer types (to name the most relevant which behave differently: pixel, mask, vector shape/curve, group, fill) being
stacked (one atop each other) nested nested to masking position grouped (pass-through and normal blend mode) nested to group nested to masking position of group  Whenever I thought I fully got how it works, I find a new edge case which surprises me.
Please do not post any links with general information about layer and alpha blending. I have read almost all at least ten times.
What is missing is a definite documentation how Affinity works (means: is designed to work) in the specific situations. As there are many unfixed bugs regarding handling of alpha, you can't simply try it out, as it is never clear if it works as designed or is broken.

To give this another direction: It would be really really great if Affinity (James?) would provide some tutorials how all this combines:
Color opacity Layer opacity Fill opacity (from Layer FX) Blend differences wrt alpha /opacity of Fill layers vs. all other types of layers And other areas or arcane secrets like
Brush Opacity Brush Flow Brush Accumulation Fun explosion: In combination with all these alpha blend options mentioned above And more arcane secrets of layer blending
layers following normal alpha compositing blend rules (pixel, curves, ...) layers able to overwrite blend rules (PT Filter, alpha-impacting adjustments levels , curves, channel mixer: just set/define new alpha value) How all this integrates
layers flat atop each other layers nested to description of ordinary layers layers nested to thumbnail of ordinary layers (masking / clipping position) layers nested to description of group layers layers nested to thumbnail of group layers layers nested to stacking groups (alpha reduced to 0 / 1)

+1
 
Select > Red
Select > Greens
Select > Blues
is just no control whatsoever

I just made a shocking observation.
Testing both on Windows PC and on MacBook Air (Retina, 12-inch, 2018), attached to the same 10 bit capable LG HDR display (see my signature for details):
By default, in RGB/8 and RGB/16, Affinity apps only render in 8 bit color channel depth: 256 unique levels.
This means, even if rendering RGB/16 files, you are unable to the see the fine details of the lower 8 bits, leading to visible banding which might be not in the document.
Only when you switch to RGB/32, Affinity is capable to utilize HDR / EDR displays and 10 (or 12) bit color depth.
The problem: the conversion is not fully lossless, and under Windows, the 32 bit preview is broken. You cannot adjust the gamma settings to 2.2., leading to wrong rendering. The gamma slider effect is reversed on Win vs. the correct one on Mac.
Coming back to the original question of @Peder:
I need to convert the image to RGB/32 to be able to see if there is banding or no banding. Stay tuned.
Unfortunately, it might be impossible to screen grab those RGB/32 renderings and share the result with you.
Update:
In RGB/32, there is no visible banding.
Using the (Apple) Preview App: no Banding, too.
So the banding is actually only a "phantom" problem: Except when using RGB/32,Affinity Photo renders in 8 bit color depth, for all document color formats.
 
 

I ran across the following WebP review shortly after reading this thread. A less than glowing review of WebP by a photographer and image processing engineer. It would seem that while shrinking images is extremely valuable to Google, it's less so for photographers especially given the quality concessions. 
https://eng.aurelienpierre.com/2021/10/webp-is-so-great-except-its-not/

I ran across the following WebP review shortly after reading this thread. A less than glowing review of WebP by a photographer and image processing engineer. It would seem that while shrinking images is extremely valuable to Google, it's less so for photographers especially given the quality concessions. 
https://eng.aurelienpierre.com/2021/10/webp-is-so-great-except-its-not/

+1
I still find selection one of the most time consuming aspects of APh and don't feel creating object selection masks is part of the creative endeavor. Thx

I use the Select Color Range tool in PS almost daily.  The limitations in the AP Select Sampled Color tool makes it frustratingly useless in my applications. I would like these features added:
Add or subtract from selection with additional clicks on the image.
Additional options for viewing selection beyond marching ants, e.g., overlay, black on white, etc.

Wow! Not clear how much of this I have experienced, clearly there are times when my results does not look great, but since still on the learning curve would have attributed that to lack of skill/knowledge or initial image quality. I have my setting generally to best rendering over speed.
Based on above I should be able to create a merge visible and use diff blend mode to spot issues. Thx

Currently, Affinity Photo does not provide a absolute trustworthy preview of the current document.
For any zoom levels not equal to 100%, you get misleading rendering of noise and unsharp mask filters With View Mode "Bilinear", you will always get false rendering on pixel level at hard edges Even with zoom level 100%, you could get get false rendering when dealing with pixel art For zoom level below 100%, you could get completely wrong colors caused by resampling (same bug report above) Many live filters can introduce rendering artifacts at any zoom level, including 100%, leading to severe deviations from final result, especially when combined with blend mode "difference" The false color by resample issue could bite you at almost any zoom level except 400% and integer multiples of 400%  
The only way to get a reliable preview of your document is to either
Export - leaving the application The Export Preview is cumbersome to use (modal windows, not able to use navigator panel) Merge visible - introducing superfluous temporary layers, must be created on top of layer stack and deleted after use. To overcome all these issues, it would be helpful if Photo would offer an "absolute trustworthy preview" move, similar to Designers View Modes.
Requirements:
No color artifacts (false colors) by resample in case of zoom <100% (use color-correct average, not false sub-sample) utilize full display color depth (10-bit, 12-bit, …) to avoid banding in case of 16-bit documents 100% accurate rendition of result ability to zoom to any level (at least -8x to + 8x) Ultimate priority on accuracy, no priority on performance. Options to deal with non-opaque pixels (color of matting background), switching options while in preview Regular keyboard shortcuts and mouse actions to zoom / pan

+1
I still find selection one of the most time consuming aspects of APh and don't feel creating object selection masks is part of the creative endeavor. Thx

https://ninedegreesbelow.com/photography/linear-gamma-blur-normal-blend.html
http://www.ericbrasseur.org/gamma.html
https://docs.krita.org/en/general_concepts/colors/linear_and_gamma.html
Watch both links. Gimp v2.10.28 gamma is perfect, Pass my test.
this modification to give more space to darker values does lead to wonky color maths when mixing the colors.
We can see this with the following experiment:

Left: Colored circles blurred in a regular sRGB space. Right: Colored circles blurred in a linear space.
Colored circles, half blurred. In a gamma-corrected environment, this gives an odd black border. In a linear environment, this gives us a nice gradation.
This also counts for color smudge brush:

That’s right, the ‘muddying’ of colors as is a common complaint by digital painters everywhere, is in fact, a gamma-corrected colorspace mucking up your colors. If you had been working in LAB to avoid this, be sure to try out a linear rgb color space.

Is there a possibility for assigning a keyboard shortcut to apply a desired macro? This could speed up workflow significantly compared to clicking in the library panel...
 
 
 

Hi,
 
it would be really great if the option "Preserve Alpha" would be accompanied by "Only Alpha":
E.g. a live blur filter that only affects alpha channel instead of RGB channels.
This option would really simplify many non-destructive workflows and eliminate lots of (destructive) workarounds.
 
More general: i would like to have the option to select which channel gets impacted by filters or adjustments.
Currently, only 3 adjustments offer this option (curves, levels, channel mixer).
 

I would like an option like PS (Blend RGB colors using gamma). 
I ran across the video Computer Color is Broken (https://www.youtube.com/watch?v=LKnqECcg6Gw) which demonstrated the effect of not factoring gamma into operations. It also showed the PS option (Blend RGB colors using gamma) to address this issue. I don’t have PS to test the option myself, maybe someone else can contribute.
I do not know the inner workings of APh, but a simple test (attached) with the Gaussian filter exhibits the same dark band issue for adjacent colors (top half). Adding a Procedural Texture filter before the Gaussian to square the color-values and one after the blur taking the square-root of the color-values appears to eliminate the dark band and yields a more pleasing transition (bottom half). Thx

GammaBlurTest.afphoto

Very likely exactly what I did, thanks Walt. As a long time Windows user now using a Mac, I never thought tab would have an app specific assignment. I enabled use tab to advance through dialogs, apparently that's not so much a thing as with Windows. Anyway I reassigned Toggle UI, so issue resolved.

Small celebration. I've just passed the 700th video in my InAffinity YouTube channel.
There's also a web-based index, including videos sorted by time and category, plus free resources.
I'd also like to take this opportunity to pay tribute to Serif and all of its people, including devs, QA, and everyone else. You folks have created an amazing product that has freed many of us from the Adobe taxation system and indeed that stands on its own as an excellent photo editing and graphics system. Having worked in software development, quality, marketing and other areas, I have some inkling of the effort and sheer dedication that it takes. Thank you and well done.
 
 

Very likely exactly what I did, thanks Walt. As a long time Windows user now using a Mac, I never thought tab would have an app specific assignment. I enabled use tab to advance through dialogs, apparently that's not so much a thing as with Windows. Anyway I reassigned Toggle UI, so issue resolved.

Hi
How do I prevent the clone tools from defaulting to 'Current Layer' all the time?

James Ritson did a video where he created a bunch of adjustments, then copied them, started recording a macro, then pasted them, and ended recording. The results was a macro with one step titled Paste. While there are limitations vs recording individual actions, it does work around the current lack of editing capabilities.
I just tried this on approach with the 1.9.4.243 beta and it did not work as expected. While the adjustments were created, it appears that a curve was only applied to the size of the image during recording not during playback. 

Old Bruce is correct it's just for top level app items, which in this case is Affinity Photo Beta. In my stupor I interpreted it as separate settings for the beta. It's obvious now after a break. thanks anyway 

Ha!
Hold on, here's the clue:
It's ye olde DEFAULT ENGLISH (UK) LANGUAGE BUG!
The (temporary) fix:
Change the app language from English (or Default) to English US (or any other language you can read).
English US is what I'm using anyway – and thus suffering from all those related bugs elsewhere – hence I've never encountered this issue until now.
P.S. Although seeing that others are using e.g. German and having this bug anyway, it's likely not the only "source". Worth to try though.