starred/terminal
1
0
Fork 0
mirror of https://github.com/microsoft/terminal.git synced 2026-02-04 05:35:20 +00:00
Code Issues 19.0k Packages Projects Releases 20 Wiki Activity

[PR #7223] Add support for the "doubly underlined" graphic rendition attribute #26867

New Issue
Open
opened 2026-01-31 09:18:36 +00:00 by claunia · 0 comments
claunia commented 2026-01-31 09:18:36 +00:00
Owner
Copy Link

Original Pull Request: https://github.com/microsoft/terminal/pull/7223

State: closed
Merged: Yes

This PR adds support for the ANSI doubly underlined graphic rendition
attribute, which is enabled by the SGR 21 escape sequence.

There was already an ExtendedAttributes::DoublyUnderlined flag in the
TextAttribute class, but I needed to add SetDoublyUnderlined and
IsDoublyUnderlined methods to access that flag, and update the
SetGraphicsRendition methods of the two dispatchers to set the
attribute on receipt of the SGR 21 sequence. I also had to update the
existing SGR 24 handler to reset DoublyUnderlined in addition to
Underlined, since they share the same reset sequence.

For the rendering, I've added a new grid line type, which essentially
just draws an additional line with the same thickness as the regular
underline, but slightly below it - I found a gap of around 0.05 "em"
between the lines looked best. If there isn't enough space in the cell
for that gap, the second line will be clamped to overlap the first, so
you then just get a thicker line. If there isn't even enough space below
for a thicker line, we move the offset above the first line, but just
enough to make it thicker.

The only other complication was the update of the Xterm256Engine in
the VT renderer. As mentioned above, the two underline attributes share
the same reset sequence, so to forward that state over conpty we require
a slightly more complicated process than with most other attributes
(similar to Bold and Faint). We first check whether either underline
attribute needs to be turned off to send the reset sequence, and then
check individually if each of them needs to be turned back on again.

Validation Steps Performed

For testing, I've extended the existing attribute tests in
AdapterTest, VTRendererTest, and ScreenBufferTests, to make sure
we're covering both the Underlined and DoublyUnderlined attributes.

I've also manually tested the SGR 21 sequence in conhost and Windows
Terminal, with a variety of fonts and font sizes, to make sure the
rendering was reasonably distinguishable from a single underline.

Closes #2916

**Original Pull Request:** https://github.com/microsoft/terminal/pull/7223 **State:** closed **Merged:** Yes --- This PR adds support for the ANSI _doubly underlined_ graphic rendition attribute, which is enabled by the `SGR 21` escape sequence. There was already an `ExtendedAttributes::DoublyUnderlined` flag in the `TextAttribute` class, but I needed to add `SetDoublyUnderlined` and `IsDoublyUnderlined` methods to access that flag, and update the `SetGraphicsRendition` methods of the two dispatchers to set the attribute on receipt of the `SGR 21` sequence. I also had to update the existing `SGR 24` handler to reset _DoublyUnderlined_ in addition to _Underlined_, since they share the same reset sequence. For the rendering, I've added a new grid line type, which essentially just draws an additional line with the same thickness as the regular underline, but slightly below it - I found a gap of around 0.05 "em" between the lines looked best. If there isn't enough space in the cell for that gap, the second line will be clamped to overlap the first, so you then just get a thicker line. If there isn't even enough space below for a thicker line, we move the offset _above_ the first line, but just enough to make it thicker. The only other complication was the update of the `Xterm256Engine` in the VT renderer. As mentioned above, the two underline attributes share the same reset sequence, so to forward that state over conpty we require a slightly more complicated process than with most other attributes (similar to _Bold_ and _Faint_). We first check whether either underline attribute needs to be turned off to send the reset sequence, and then check individually if each of them needs to be turned back on again. ## Validation Steps Performed For testing, I've extended the existing attribute tests in `AdapterTest`, `VTRendererTest`, and `ScreenBufferTests`, to make sure we're covering both the _Underlined_ and _DoublyUnderlined_ attributes. I've also manually tested the `SGR 21` sequence in conhost and Windows Terminal, with a variety of fonts and font sizes, to make sure the rendering was reasonably distinguishable from a single underline. Closes #2916
claunia added the pull-request label 2026-01-31 09:18:36 +00:00
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 pull-request
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#26867
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?