Dim escape code in terminal should not effect background color

[willmcgugan]

Type: Bug

The dim ansi escape sequence SGR 2 changes both the foreground and background color in the vscode terminal. AFAICT other terminals only alter the text color.

Reproduce with the following python code:

print('\x1b[2;41mHello\x1b[0m\n\x1b[41mHello\x1b[0m\n')

On vscode, the background color of the dim text appears blended with the window color. On other terminals the background red is the same on both lines.

Output on vscode

Output on iTerm for MacOS

BTW I disabled the "minimum contrast ration" setting by setting it to 1.

VS Code version: Code 1.71.2 (74b1f97, 2022-09-14T21:07:15.900Z)
OS version: Darwin arm64 21.6.0
Modes:
Sandboxed: No

System Info

Item	Value
CPUs	Apple M1 Pro (10 x 24)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: disabled_off direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled metal: disabled_off multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_renderer: enabled_on video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: disabled_off
Load (avg)	5, 5, 4
Memory (System)	16.00GB (0.27GB free)
Process Argv	--crash-reporter-id 708fb231-9126-40c3-a471-56c4901cf66d
Screen Reader	no
VM	0%

Extensions (48)

Extension	Author (truncated)	Version
vscode-sqlite	ale	0.14.1
vscode-color	ans	0.4.5
vscode-database	baj	2.2.3
vscode-django	bat	1.10.0
better-toml	bun	0.3.2
vscode-svgviewer	css	2.0.0
vscode-eslint	dba	2.2.6
xml	Dot	2.5.1
vsc-material-theme	Equ	33.5.0
vsc-material-theme-icons	equ	2.4.0
prettier-vscode	esb	9.8.0
code-runner	for	0.11.8
vscode-pull-request-github	Git	0.50.0
sass-lint	gle	1.0.7
gc-excelviewer	Gra	4.2.55
vscode-peacock	joh	4.2.1
chat	kar	0.35.0
restructuredtext	lex	189.2.0
dotenv	mik	1.0.1
theme-monokai-pro-vscode	mon	1.1.21
black-formatter	ms-	2022.5.12591021
python	ms-	2022.14.0
vscode-pylance	ms-	2022.9.20
jupyter	ms-	2022.8.1002431955
jupyter-keymap	ms-	1.0.0
jupyter-renderers	ms-	1.0.9
vsliveshare	ms-	1.0.5723
vsliveshare-audio	ms-	0.1.91
vsliveshare-pack	ms-	0.4.0
color-highlight	nau	2.5.0
autodocstring	njp	0.6.1
hide-gitignored	npx	1.1.0
vetur	oct	0.36.0
austin-vscode	p40	0.10.8
material-icon-theme	PKi	4.20.0
excalidraw-editor	pom	3.3.1
vscode-commons	red	0.0.6
vscode-yaml	red	1.10.1
LiveServer	rit	5.7.9
snappify	sna	1.0.1
code-spell-checker	str	2.8.0
sass-indented	syl	1.8.22
cython	tcw	0.1.0
simple-rst	tro	1.5.2
luna-paint	Tyr	0.16.0
vscode-icons	vsc	11.17.0
markdown-all-in-one	yzh	3.4.3
material-theme	zhu	3.15.5

(3 theme extensions excluded)

A/B Experiments

vsliv368cf:30146710
vsreu685:30147344
python383cf:30185419
vspor879:30202332
vspor708:30202333
vspor363:30204092
vslsvsres303:30308271
pythonvspyl392:30443607
vserr242cf:30382550
pythontb:30283811
vsjup518:30340749
pythonptprofiler:30281270
vshan820:30294714
vstes263:30335439
vscorecescf:30445987
pythondataviewer:30285071
vscod805:30301674
binariesv615:30325510
bridge0708:30335490
bridge0723:30353136
cmake_vspar411:30557514
vsaa593:30376534
pythonvs932:30410667
cppdebug:30492333
vsclangdf:30486550
c4g48928:30535728
hb751961:30553087
dsvsc012cf:30540253
azure-dev_surveyone:30548225
i497e931:30553904
fc301958:30567733

[meganrogge]

Related to xtermjs/xterm.js#3534

[meganrogge]

We changed this to align with xterm and VTE (Gnome terminal / Konsole). While ITerm doesn't do this (yet?), we went with what most terminals do

[vscodenpa]

The described behavior is how it is expected to work. If you disagree, please explain what is expected and what is not in more detail. See also our issue reporting guidelines.

Happy Coding!

[willmcgugan]

I don't think that's the case. I ran a straw poll on Twitter, and it was a virtual consensus that dim does not change the background color.

https://twitter.com/willmcgugan/status/1572208240493985793

This isn't actually related to xtermjs/xterm.js#3534 The code I pasted above changes background and foreground colors, but doesn't apply the escape code for inverse.

[willmcgugan]

@meganrogge Could you take another look at this one? I've confirmed that vscode is unique in this behaviour.

Here are screenshots from gnome terminal and xterm:

[Tyriar]

Yeah looks like a problem, thanks