1px line between powerline glyphs

[kaysond]

Environment

Windows build number: Microsoft Windows [Version 10.0.19042.746]
Windows Terminal version (if applicable): 1.5.10271.0 & 1.6.10272.0

Steps to reproduce

Install any nerdfont
Set up anything that uses powerline glyphs (in my case, bobthefish plugin on fish shell)

Expected behavior

Clean rendering/placement of powerline glyphs (see Color schemes @ https://github.com/oh-my-fish/theme-bobthefish)

Actual behavior

The glyphs have a 1px line of the adjacent glyph color

Funnily enough, you can see the same thing in the powerline setup tutorial: https://docs.microsoft.com/en-us/windows/terminal/tutorials/powerline-setup

Setting "useAcrylic": true and "acrylicOpacity" : 0.899 fixes one glyph, but not the other:

I've tried a variety of rendering options, fonts, sizes, etc, but none completely solve the problem. I also have the Windows text scaling set to 100%. I am on a high-dpi monitor (2560x1440) though.

I searched around and found #3626 #455 #4930 #633 #6669 but those aren't quite what's happening here. Sorry if I missed a dupe.

[zadjii-msft]

#5897 and #373 both also look similar as well. I thought we were tracking this somewhere specifically, @miniksa might know where.

[miniksa]

There isn't a specific place. Those links and this issue are good enough.

[Ririshi]

I'm seeing the same issue with Cascadia Code PL, only when using cleartype antialiasing. I tested it on font sizes between 10 and 20 and it seems like all sizes suffer from it.

Example below with Powershell 7.1.2 using oh-my-posh v3 and the paradox theme:

It seems like the triangular shapes are shifted one pixel to the right when using cleartype AA, showing the background color. I'm unsure why the leftmost shape has a red line, though. If you look closely, you can also see the lines on the other triangular shapes. Upscaled 800% with nearest neighbour scaling:

[nitz]

I'm also seeing this issue with my setup, on preview 1.10.1933.0.

Config:

    "defaults": {
      "fontFace": "MesloLGS Nerd Font",
      "fontWeight": "normal",
      "useAcrylic": true,
      "acrylicOpacity": 0.4,
      "hidden": false,
      // also occurs worse with 'cleartype', but not with 'aliased'
      "antialiasingMode": "grayscale",
      "fontSize": 10
    },

Example of what I'm seeing, definitely with the  characters, but also with several other glyphs.

I thought, perhaps it's because I'm using the non-mono NF? Well, that produces even weirder issues switching to it.

"fontFace": "MesloLGS Nerd Font"	"fontFace": "MesloLGS Nerd Font Mono"
"Apple" glyph cut off, as are the triangle and cap characters showing issues.	Apple glyph no longer cut as all symbol glyphs appear smaller, but the caps are still showing issues. Additionally, the 'flame' glyphs appear to be doubled.

It definitely seems to be something related to the antialiasing, given that using "aliased" doesn't show the issue at all. Meanwhile, "cleartype" can make it appear worse. Additionally, it seems that the fontSize has an effect on it as well.

"aliased"	"cleartype"	"grayscale"
No rendering issues, but not lovely to look at.	Issues left round cap, as well as triangle glyphs.	Triangle issue gone, cap issue persists.

[miniksa]

Thank you for the investigation and various screenshots, @nitz. I'm wondering if @lhecker's plans to do #10461 will end up sorting this out since I believe it uses slightly different measurements and anti-aliasing phases than what we're currently doing.