Pixel Preview Inaccuracy in Symmetry Mode

I think it's a bug...
#1

This is a very small thing I’ve just noticed, but when in either Multi Dot Mirror or Multi Dot Circle symmetry mode, the pixel previews are off by one pixel in some cases when the cursor is exactly on the border between two pixels. It’s a bit hard to explain, maybe the gif will illustrate it a bit better:

capture
capture755×569 239 KB

This is by no means a serious issue, but I thought I’d mention it regardless.

#2

Looks like a rounding problem. Will have a look at this.

1 Like
#3

Could not duplicate :frowning:
I guess it happens with certain sizes, so my question is:

  1. what size has your project?
  2. Where is the symmetry center placed?
  3. what zoom level do you use?
#4

I lost the project this bug originally occurred on, but I was able to reproduce it. I tried both loading old projects and creating new 64x64 projects. In all cases, regardless of the Center’s placement the bug was present. I’ve tried zoom levels from x1 all the way to x50, the bug persists regardless of the used zoom level. The Dots counts I’ve tried were 2 and 4, both of which had pretty much the same issues.

I’ve accidentally found a different variation of this bug while playing with it in a temporary project, I don’t know what triggered this behavior, because it only happens within the said project:
The pixel previews are not offsetting anymore, i.e. moving the mouse near the borders does not cause one pixel to move while the other stays, but the borders themselves are distorted and don’t line up with the pixel previews:

capture3
capture3818×636 81.6 KB

This is very hard to put into words, but attempting to draw while the mouse cursor is out of the pixel preview causes some pixels to be drawn in the place of their pixel previews, and some pixels choose to be drawn in place of the mouse instead, e.g.:

capture4
capture4818×636 249 KB

I’m guessing what happens above is, the pixel preview instead of glitching while the cursor gets near the border, somehow has an offset off said border instead. It’s worth mentioning that the distance the mouse cursor is able to travel outside the pixel preview varies both horizontally and vertically depending on where the mouse is. I haven’t noticed a consistent rule dictating how far it can go, but it seems like the offset is always the same for the same pixels, regardless of the zoom level as well.

Preview of the varying offsets:

capture5
capture5818×636 1.4 MB

Preview of the offset not changing for the same pixels regardless of zoom level:

capture6
capture61044×794 945 KB

I hope this will help in tracking the problem. Here’s the project file I’ve been using for the previews on the “second variation” of the bug:
http://s000.tinyupload.com/index.php?file_id=92676217427033837317

Side note: the issues appear in the exact same way after closing & reopening PM or closing & reloading the project file.

#5

Couple more things:

  • Changing the symmetry center causes the offsets (i.e. the distances the mouse cursor can travel outside of the pixel previews) to change,
  • The offsets are always the same for Multi Dot Mirror and Multi Dot Cycle modes,
  • The offsets stay the same when changing the Dot count,
  • None of the described issues happen in X and Y Mirror modes.
#6

Thank you for all the details! Will try to dig through :slight_smile:

1 Like
#7

I fixed this. Available with next beta (hopefully tomorrow). Would be great if you could check it then.
Thanks again for your help.

#8

Sure will, thanks as always.