Synchronized Output (DEC mode 2026)

[l2dy]

Checklist

• Using latest version on the App Store
• Read the docs
• Searched for existing GitHub issues

Describe the bug

"The goal of synchronized updates is to avoid showing a half-drawn screen, such as while paging through a document in an editor.

A new control sequence is proposed that indicates the beginning and end of a update. No new content should be rendered by the terminal emulator until the update ends, at which point any changes made during the update should be applied atomically.

The purpose of this sequence is to provide a hint to the terminal emulator about how to draw atomically. If it turns out to be too difficult to do under some particular input, the hint can be safely ignored."

Original proposal: https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec
Living document: https://gist.github.com/christianparpart/d8a62cc1ab659194337d73e399004036
Spec discussion: https://gitlab.freedesktop.org/terminal-wg/specifications/-/merge_requests/2

[carloscabanero]

Grouped on #1980