Unicode box characters don't render correctly in terminal

[willmcgugan]

Does this issue occur when all extensions are disabled?: Yes/No

Yes

• VS Code Version: Version: 1.67.2
• OS Version: macOS 12.4

My project uses unicode box characters to render scrollbars in the terminal. They don't render as expected in the vscode terminal.

Here's the scrollbars in the VSCode terminal:

Screen.Recording.2022-05-31.at.08.54.46.mov

Here's how the scrollbars look in iTerm on MacOS (and other terminal emulators):

Screen.Recording.2022-05-31.at.08.54.02.mov

It looks as though these box characters render with the wrong color. The border around the window above is also rendered with the same box characters, and produces a darker color in VSCode.

Steps to Reproduce:

I've isolated a string which demonstrates the issue (in Python)

scrollbar = '\x1b[48;2;85;85;85m \x1b[0m\x1b[38;2;85;85;85;105m▋\x1b[0m\x1b[105m \x1b[0m\x1b[105m \x1b[0m\x1b[105m \x1b[0m\x1b[105m \x1b[0m\x1b[95;48;2;85;85;85m▋\x1b[0m\x1b[48;2;85;85;85m \x1b[0m\x1b[48;2;85;85;85m \x1b[0m\x1b[48;2;85;85;85m \x1b[0m\n'
print(scrollbar)

This produces the following in iTerm:

And in VSCode:

[yume-chan]

Another issue caused by terminal.integrated.minimumContrastRatio

1:

4.5:

[Tyriar]

We should also exclude box drawing characters from the setting, anything decorative.

[Tyriar]

Upstream xtermjs/xterm.js#3843

[aeschli]

After fix:

Marking as verified.

[willmcgugan]

You guys are awesome.