Fill color of object bleeds past stroke set to inline

[Vibe Design]

I noticed that when the stroke of an object is set to inline that the fill color of that object is clearly bleeding through behind the stroke. I don't think that's supposed to be as it would mean the stroke is not aligned properly with the border of the object. As you can see this also transfers to exports and is not just a visual glitch. In my example image I have a simple circle, filled with black and on top of that a smaller circle with a white fill and a black stroke set to inline. You can clearly see the white bleed on the border of the inner circle. The bleed also changes with the color of the inner circle's fill. Is there any settings I might have wrong to fix this or is this a bug?

[lepr]

The hairline is a result of each object being independently antialiased in the process of rasterising for output to the display or a raster file, and an inside-aligned (and outside-aligned) stroke actually being implemented as a separate filled shape rather than a true stroke.

In your example, the outer edge of the black pseudo stroke exactly matches the outer edge of the white shape, but the edge pixels of the raster representation of each of these objects (and the bottom black larger Circle) are partially opaque to achieve antialiasing. Partially opaque black pixels of the rasterised pseudo stroke are partially revealing underlying partially opaque white pixels, which in turn are partially revealing underlying black pixels of the bottom black circle.

This is a limitation of the rendering engine rather than a bug and it is found in many apps. It may be many years until the Affinity team come up with an improvement.

I would say export a super-sized (for example, 800%) raster image and then resample that to the 100% size; that will make the hairline artefacts unnoticeable. 
Unfortunately, that invokes a rendering bug which produces spikes on the inside edge of the rasterised pseudo stroke.

[Vibe Design]

Thank you for your response! Although of course, really not what I had hoped to hear. This basically makes inline strokes unusable.

42 minutes ago, anon2 said:

This is a limitation of the rendering engine rather than a bug and it is found in many apps. It may be many years until the Affinity team come up with an improvement.

I have used different (both paid and open source) vector manipulation software in the past and none of them had this issue, but I guess it comes down to this:

45 minutes ago, anon2 said:

an inside-aligned (and outside-aligned) stroke actually being implemented as a separate filled shape rather than a true stroke

So why is it that way? I guess there are are plenty of good reasons to do it this way (and accept other downsides therefore).

47 minutes ago, anon2 said:

I would say export a super-sized (for example, 800%) raster image and then resample that to the 100% size; that will make the hairline artefacts unnoticeable. 
Unfortunately, that invokes a rendering bug which produces spikes on the inside edge of the rasterised pseudo stroke.

Thank you for this possible workaround, that's not usable in a professional environment though, I don't really want to trade one bug for another.

I guess for now I just have to avoid inline strokes completely...