Does the fill tool use the entire image?

[Reptorian]

While over the PDN discord, someone shared a 41k*21k image of Earth with coastline outline. So, I tested the fill tool on Paint.NET and Krita. It appears that Krita fill tool is significantly slower than it is on Paint.NET. Which raises a question of whether the fill tool tries to analyze the entire image. Just trying to fill in a 1 px with border takes 5-10 s where it’s fast on Paint.NET.

Could it be possible to enforce local analysis?

[freyalupen]

There was a thread a few months ago discussing the speed of the Fill Tool:

Fill Tool lag (again and again)

Hello, I like very much Krita but it’s impossible to work on basic comic coloring with it because of the fill tool is so laggy. I have the problem with my two PC (Win 10), different CPU (Amd and Intel), different graphic card. I have no lag problem - 32 Go Ram ! - with brushes but the fill tool is driving me crazy. On CSP or Photoshop, filling the same little zone is done without delay. In Krita, it can took several seconds. I’ve tested and read all I could about this kind of problem but nothi…

From that some improvements were made in the 5.3 branch, including to only update the part of image that was changed so the speed wouldn’t be dependent on image size:

Improve performance of fill tools (!2125) · Merge requests · Graphics / Krita...

[Reptorian]

Oh yeah, I remember that now. Thing is, with large images that are closer to binary in terms of color, I don’t think I noticed significant speed-up here. Still slow for that purpose, when it should be responsive in that case.