[enhancement]: Improve viewport zoom scaling quality (reduce aliasing)

[Kahldris]

Is there an existing issue for this?

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What should this feature add?

Just a quick observation/suggestion regarding the image display when zooming in the canvas/viewer. I immediately noticed that at zoom levels other than 100%, images (especially with lineart) can look quite aliased or "jaggy" (see attached image comparing with how Photoshop handles it).

I guess Invoke is just using nearest-neighbor scaling, rather than something like bilinear/bicubic filtering which helps smooth things out. It can make it a bit tricky to work with finer details when not at 100% zoom and gets a bit annoying having to always reset it back to 100% to properly assess quality.

I couldn't find any discussion about it so I don't know if there's a way to enable better filtering that I missed. Apps like Nvidia ICAT default to nearest neighbor but have a toggle for bilinear which would be great here. I don't know if there's a technical limitation but I'd love if better viewport scaling could be considered for a future update. Love the tool otherwise!

Cheers

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[psychedelicious]

The HTML Canvas API is rather limited in this regard. It has an "image smoothing" setting - either on or off.

The library used by Canvas for rendering makes it difficult to separate the view and the actual image data. We've had issues with smoothing and progressive quality loss over repeated inpaint / image-to-image operations, and disabling smoothing fixed those issues.

That said, that change was made quite some time ago, and it's possible that internal changes to Invoke's Canvas would allow us to enable smoothing.