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

Wait before drawing the frame when receiving ESC[2J #21264

New Issue
Closed
opened 2026-01-31 07:38:06 +00:00 by claunia · 4 comments
claunia commented 2026-01-31 07:38:06 +00:00
Owner
Copy Link

Originally created by @a-usr on GitHub (Feb 16, 2024).

Description of the new feature/enhancement

Wait before drawing ( or creating ) a frame when ESC[2J (Clear Screen) is received until either a set time (e.g. 2 ms) has passed or additional data is received from stdout or stderr. This is to prevent flickering caused by applications (that do frame-based rendering, e.g TUI applications) that clear the screen before writing the next frame to it. If such a feature already exists, I propose making the timeout higher.

Worth noting is that the Flickering seems to be more intense on windows 11 vs on windows 10. Do the two platforms have different max framerates or is the framerate not capped at all and its caused by a hardware difference?

Proposed technical implementation details (optional)

Originally created by @a-usr on GitHub (Feb 16, 2024). <!-- 🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨 I ACKNOWLEDGE THE FOLLOWING BEFORE PROCEEDING: 1. If I delete this entire template and go my own path, the core team may close my issue without further explanation or engagement. 2. If I list multiple bugs/concerns in this one issue, the core team may close my issue without further explanation or engagement. 3. If I write an issue that has many duplicates, the core team may close my issue without further explanation or engagement (and without necessarily spending time to find the exact duplicate ID number). 4. If I leave the title incomplete when filing the issue, the core team may close my issue without further explanation or engagement. 5. If I file something completely blank in the body, the core team may close my issue without further explanation or engagement. All good? Then proceed! --> # Description of the new feature/enhancement Wait before drawing ( or creating ) a frame when ESC[2J (Clear Screen) is received until either a set time (e.g. 2 ms) has passed or additional data is received from stdout or stderr. This is to prevent flickering caused by applications (that do frame-based rendering, e.g TUI applications) that clear the screen before writing the next frame to it. If such a feature already exists, I propose making the timeout higher. Worth noting is that the Flickering seems to be more intense on windows 11 vs on windows 10. Do the two platforms have different max framerates or is the framerate not capped at all and its caused by a hardware difference? <!-- A clear and concise description of what the problem is that the new feature would solve. Describe why and how a user would use this new functionality (if applicable). --> # Proposed technical implementation details (optional) <!-- A clear and concise description of what you want to happen. -->
claunia added the Issue-FeatureNeeds-TriageNeeds-Tag-Fix labels 2026-01-31 07:38:06 +00:00
claunia commented 2026-01-31 07:38:07 +00:00
Author
Owner
Copy Link

@a-usr commented on GitHub (Feb 16, 2024):

For additional context, apparently the Flickering doesnt seem to be an issue with other terminals like WezTerm, but I havent tested this myself.

@a-usr commented on GitHub (Feb 16, 2024): For additional context, apparently the Flickering doesnt seem to be an issue with other terminals like WezTerm, but I havent tested this myself.
claunia commented 2026-01-31 07:38:07 +00:00
Author
Owner
Copy Link

@lhecker commented on GitHub (Feb 17, 2024):

In the current architecture it would be slightly difficult to implement this right now, but it would be generally possible long term. Your suggestion wouldn't work well over SSH though. Other terminals have since adopted iTerm2's synchronized update sequence (BSU = 2026) which does what you'd like but in a more robust manner. You can read about it here: https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec
Support for BSU is tracked in #8331. If that matches what you want, then I believe we should continue tracking this in #8331.

That said, and unrelated to the above, if you use the very latest Windows Terminal version and if you ensure to write your sequences in a single "packet" using the Windows APIs (= WriteFile on stdout) then it should not flicker.
C's printf for instance has an internal buffer size of 4KiB and any printf larger than that will chunk it up which causes flickering. WSL also does some buffering internally which causes the same thing. But if you use a native Windows function to write your output and buffer it properly then it should already work.

@lhecker commented on GitHub (Feb 17, 2024): In the current architecture it would be slightly difficult to implement this right now, but it would be generally possible long term. Your suggestion wouldn't work well over SSH though. Other terminals have since adopted iTerm2's synchronized update sequence (BSU = 2026) which does what you'd like but in a more robust manner. You can read about it here: https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec Support for BSU is tracked in #8331. If that matches what you want, then I believe we should continue tracking this in #8331. That said, and unrelated to the above, if you use the very latest Windows Terminal version and if you ensure to write your sequences in a single "packet" using the Windows APIs (= `WriteFile` on stdout) then it should not flicker. C's `printf` for instance has an internal buffer size of 4KiB and any `printf` larger than that will chunk it up which causes flickering. WSL also does some buffering internally which causes the same thing. But if you use a native Windows function to write your output and buffer it properly then it should already work.
claunia commented 2026-01-31 07:38:08 +00:00
Author
Owner
Copy Link

@a-usr commented on GitHub (Feb 18, 2024):

Thanks for the explanation and the references! Also huge thanks to you for taking your time and taking a look at almost every single issue👍

@a-usr commented on GitHub (Feb 18, 2024): Thanks for the explanation and the references! Also huge thanks to you for taking your time and taking a look at almost every single issue👍
claunia commented 2026-01-31 07:38:08 +00:00
Author
Owner
Copy Link

@a-usr commented on GitHub (Feb 19, 2024):

Also I was wondering, is there any functionality to see when Windows Terminal receives a packet and what its contents are?

@a-usr commented on GitHub (Feb 19, 2024): Also I was wondering, is there any functionality to see when Windows Terminal receives a packet and what its contents are?
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 Issue-Feature Needs-Tag-Fix Needs-Triage
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#21264
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?