starred/terminal
1
0
Fork 0
mirror of https://github.com/microsoft/terminal.git synced 2026-05-06 20:34:29 +00:00
Code Issues 19.0k Packages Projects Releases 20 Wiki Activity

SGR 7 (reverse video) makes text invisible in Windows Terminal #7590

New Issue
Closed
opened 2026-01-31 01:08:01 +00:00 by claunia · 4 comments
claunia commented 2026-01-31 01:08:01 +00:00
Owner
Copy Link

Originally created by @j4james on GitHub (Apr 23, 2020).

Environment

Windows build number: Version 10.0.18362.657
Windows Terminal version (if applicable): 0.11.1121.0

Steps to reproduce

  1. Open a bash shell in Windows Terminal.
  2. Execute printf "\e[mNORMAL \e[7;38m REVERSE \e[m\n"

Expected behavior

This is a weird test case, because conpty wouldn't usually forward SGR 7, so it's relying on a "feature" in conhost that forces it to pass-through any sequence that the dispatcher doesn't understand. In this case I'm relying on SGR 38 with a missing type parameter to trigger this pass-through. What this means is that the sequences that actually get sent down the conpty pipe look more like this:

\e[7;38mNORMAL \e[30;47m REVERSE \e[m\n

So ignoring the fact that the "pass through" feature is generally a bad idea, and this sequence is wrong to start with, I'd expect it to be interpreted as black on white (i.e. reversed), followed by white on black (colors changed to black on white, but still reversed).

Actual behavior

SGR 7 somehow seems to make the text invisible, so the first part of the line is blank, and the second half is white on black. Even stranger, it makes the first part of the shell prompt on the following line invisible too.

image

This may seem like an unimportant edge case, but I actually discovered this bug while experimenting with a fix for #2661 (which ended up causing more problems than it solved). Until we can get Windows Terminal to handle all the SGR sequences correctly, I don't think we'll be able to fix issues like #2661.

Originally created by @j4james on GitHub (Apr 23, 2020). # Environment Windows build number: Version 10.0.18362.657 Windows Terminal version (if applicable): 0.11.1121.0 # Steps to reproduce 1. Open a bash shell in Windows Terminal. 2. Execute `printf "\e[mNORMAL \e[7;38m REVERSE \e[m\n"` # Expected behavior This is a weird test case, because conpty wouldn't usually forward `SGR 7`, so it's relying on a "feature" in conhost that forces it to pass-through any sequence that the dispatcher doesn't understand. In this case I'm relying on `SGR 38` with a missing type parameter to trigger this pass-through. What this means is that the sequences that actually get sent down the conpty pipe look more like this: \e[7;38mNORMAL \e[30;47m REVERSE \e[m\n So ignoring the fact that the "pass through" feature is generally a bad idea, and this sequence is wrong to start with, I'd expect it to be interpreted as black on white (i.e. reversed), followed by white on black (colors changed to black on white, but still reversed). # Actual behavior `SGR 7` somehow seems to make the text invisible, so the first part of the line is blank, and the second half is white on black. Even stranger, it makes the first part of the shell prompt on the following line invisible too. ![image](https://user-images.githubusercontent.com/4181424/80116803-52d0a380-857e-11ea-89d7-0752d21ce458.png) This may seem like an unimportant edge case, but I actually discovered this bug while experimenting with a fix for #2661 (which ended up causing more problems than it solved). Until we can get Windows Terminal to handle all the SGR sequences correctly, I don't think we'll be able to fix issues like #2661.
claunia commented 2026-01-31 01:08:03 +00:00
Author
Owner
Copy Link

@j4james commented on GitHub (Apr 23, 2020):

Another easy way to demonstrate this issue is by changing this line:

d711d731d7/src/cascadia/TerminalCore/TerminalDispatchGraphics.cpp (L135)

to this:

    return _terminalApi.ReverseText(bold);

That's essentially making the bold attribute be interpreted as reversed video, and thus any bold text becomes invisible.

@j4james commented on GitHub (Apr 23, 2020): Another easy way to demonstrate this issue is by changing this line: https://github.com/microsoft/terminal/blob/d711d731d7d00259b2e0fe5847928c9f1c1121ed/src/cascadia/TerminalCore/TerminalDispatchGraphics.cpp#L135 to this: ```cpp return _terminalApi.ReverseText(bold); ``` That's essentially making the bold attribute be interpreted as reversed video, and thus any bold text becomes invisible.
claunia commented 2026-01-31 01:08:03 +00:00
Author
Owner
Copy Link

@j4james commented on GitHub (Apr 23, 2020):

Well I finally figured this out. It's a lot more obvious what's going on if you have the acrylic effect enabled. What's happening is it's testing to see if the background color is default, and if so it makes the background transparent. When reverse video is enabled, though, the background is no longer rendered with the background color, so that test isn't valid. See here:

fe3f528827/src/cascadia/TerminalCore/terminalrenderdata.cpp (L61-L66)

Essentially we need an extra check there to make sure the background is also made opaque when reverse video is enabled. Long term it'll get more complicated once we support DECSCNM mode on the WT side, but that still shouldn't be that big a deal.

Is it worth doing a PR for this now? It's only a one line change.

@j4james commented on GitHub (Apr 23, 2020): Well I finally figured this out. It's a lot more obvious what's going on if you have the acrylic effect enabled. What's happening is it's testing to see if the background color is default, and if so it makes the background transparent. When reverse video is enabled, though, the background is no longer rendered with the background color, so that test isn't valid. See here: https://github.com/microsoft/terminal/blob/fe3f52882758812f0f7ae780dfb4987d5cb7d41d/src/cascadia/TerminalCore/terminalrenderdata.cpp#L61-L66 Essentially we need an extra check there to make sure the background is also made opaque when reverse video is enabled. Long term it'll get more complicated once we support `DECSCNM` mode on the WT side, but that still shouldn't be that big a deal. Is it worth doing a PR for this now? It's only a one line change.
claunia commented 2026-01-31 01:08:04 +00:00
Author
Owner
Copy Link

@DHowett-MSFT commented on GitHub (Apr 23, 2020):

I'd absolutely appreciate a PR here. Puzzlingly, I love learning about the deficiencies in Terminal's VT implementation. We think conhost's is okay, so when we eventually do want to converge it's another datapoint in favor of why and when and how.

@DHowett-MSFT commented on GitHub (Apr 23, 2020): I'd absolutely appreciate a PR here. Puzzlingly, I love learning about the deficiencies in Terminal's VT implementation. We think conhost's is _okay_, so when we eventually do want to converge it's another datapoint in favor of _why_ and _when_ and _how_.
claunia commented 2026-01-31 01:08:05 +00:00
Author
Owner
Copy Link

@DHowett-MSFT commented on GitHub (Apr 23, 2020):

And thank you for looking at 2661. It's my great white whale issue. 😄

@DHowett-MSFT commented on GitHub (Apr 23, 2020): And thank you for looking at 2661. It's my great white whale issue. :smile:
Sign in to join this conversation.
No Branch/Tag Specified
Branches Tags
Labels
Clear labels
⛺ Reserved
A11yCO
A11yMAS
A11ySev1
A11ySev2
A11ySev3
A11yTTValidated
A11yUsable
A11yVoiceAccess
A11yWCAG
Area-Accessibility
Area-AtlasEngine
Area-AzureShell
Area-Build
Area-Build
Area-Chat
Area-CmdPal
Area-CodeHealth
Area-Commandline
Area-CookedRead
Area-DefApp
Area-Extensibility
Area-Fonts
Area-GroupPolicy
Area-i18n
Area-Input
Area-Interaction
Area-Interop
Area-Localization
Area-Output
Area-Performance
Area-Portable
Area-Quality
Area-Remoting
Area-Rendering
Area-Schema
Area-Server
Area-Settings
Area-SettingsUI
Area-ShellExtension
Area-ShellExtension
Area-ShellExtension
Area-Suggestions
Area-Suggestions
Area-TerminalConnection
Area-TerminalControl
Area-Theming
Area-UserInterface
Area-VT
Area-Windowing
Area-WPFControl
AutoMerge
Blocking-Ingestion
Culprit-Centennial
Culprit-WinUI
Disability-All
Disability-Blind
Disability-LowVision
Disability-Mobility
External-Blocked-WinUI3
Fixed
Gathering-Data
good first issue
HCL-E+D
HCL-WindowsTerminal
Help Wanted
Impact-Compatibility
Impact-Compliance
Impact-Correctness
Impact-Visual
In-PR
InclusionBacklog
InclusionBacklog-Windows TerminalWin32
InclusionCommitted-202206
Issue-Bug
Issue-Docs
Issue-Feature
Issue-Feature
Issue-Question
Issue-Samples
Issue-Scenario
Issue-Task
Needs-Attention
Needs-Author-Feedback
Needs-Bisect
Needs-Discussion
Needs-Repro
Needs-Tag-Fix
Needs-Tag-Fix
Needs-Triage
No-Recent-Activity
Priority-0
Priority-1
Priority-2
Priority-3
Product-Cmd.exe
Product-Colortool
Product-Colortool
Product-Colortool
Product-Conhost
Product-Conpty
Product-Meta
Product-Powershell
Product-Terminal
Product-WSL
pull-request
Mirrored from GitHub Pull Request
 Resolution-Answered
Resolution-By-Design
Resolution-Duplicate
Resolution-External
Resolution-Fix-Available
Resolution-Fix-Committed
Resolution-No-Repro
Resolution-Won't-Fix
Severity-Blocking
Severity-Crash
Severity-DataLoss
spam
this-will-be-a-breaking-change
Tracking-External
WindowsTerminal_Win32
Work-Item
zAskModeBug
zInbox-Bug
No Label Area-VT Issue-Bug Needs-Tag-Fix Priority-2 Product-Terminal Resolution-Fix-Committed
Milestone
No items
No Milestone
Projects
Clear projects
No project
Assignees
Clear assignees
claunia
No Assignees
1 Participants
Notifications
Due Date
No due date set.
Dependencies

No dependencies set.

Reference: starred/terminal#7590
Delete Branch "%!s()"

Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?