Performance Considerations

[victor-livefront]

Description

MarkdownUI wraps UITextView backed by TextKit, which supports incremental text editing.

From what I understand, Textual is a pure SwiftUI implementation. StructuredText(markdown:) calls AttributedString(markdown:) synchronously on every update, which parses the entire string from scratch every time.

This is an issue for me because I'm streaming text in as it's available, so StructuredText() may happen 100s of times before I get a complete markdown doc. Markdown() did not have this issue. The result is a visual performance hit, where rendering slows down significantly.

I understand if the intention was to use a pure SwiftUI implementation, but because of this, I'm not able to use this package.

Checklist

• I have determined whether this bug is also reproducible in a vanilla SwiftUI project.
• If possible, I've reproduced the issue using the main branch of this package.
• This issue hasn't been addressed in an existing GitHub issue or discussion.

Expected behavior

Incremental UI updates. No performance issues.

Actual behavior

Rerendering of UI, with visual UI slowdown.

Steps to reproduce

No response

Textual version information

0.3.1

Destination operating system

iOS 26

Xcode version information

Xcode 26.4

Swift Compiler version information

swift-driver version: 1.148.6 Apple Swift version 6.3 (swiftlang-6.3.0.123.5 clang-2100.0.123.102)
Target: arm64-apple-macosx26.0

[Ichigo3766]

@victor-livefront Hey! I was running into similar issues and more with this library. Are there any alternatives you have found for this? I was working on a fork of a different one and have improved it quite a lot but still see a lag when rendering a lot of text as im also streaming ai responses.

[victor-livefront]

@victor-livefront Hey! I was running into similar issues and more with this library. Are there any alternatives you have found for this? I was working on a fork of a different one and have improved it quite a lot but still see a lag when rendering a lot of text as im also streaming ai responses.

Nah, I just kept the existing implementation that used swift-markdown-ui. No refresh issues in that one.