jupyterlab/jupyterlab

Switching to markdown preview is slow; the scroll position gets lost

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#13,678 建立於 2022年12月29日

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bughelp wantedpkg:markdownviewertag:Performance

描述

Description

Switching tabs to markdown viewer is slow. It takes ~11 partially presented frames and renderMarkdown gets called twice.

Reproduce

  1. Open JupyterLab README.md with right click: "Open With" → "Markdown Preview"
  2. Open a new launcher
  3. Switch back and forth
  4. See that the markdown tab contents flickers

Screenshot from 2022-12-29 13-51-24

Screenshot from 2022-12-29 13-56-06

For scroll position not being preserved see:

scroll-position-md

Expected behavior

  • We should not need to invalidate the rendered markdown when switching back and forth and definitely we should not call renderMarkdown twice.
  • The scroll position should be preserved.

Context

  • JupyterLab version: 4.0.0a31 and 3.x

貢獻者指南

技術棧
typescript
領域
frontend
議題類型
performance
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
3
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
half day
活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。
stale
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
clear
前置要求
無
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
40
研究方向
Investigate the markdown preview widget implementation in JupyterLab. Look for the 'renderMarkdown' function calls and understand why it is invoked twice when switching tabs. Examine the widget lifecycle and caching mechanism to avoid re rendering. Also, check how scroll position is stored and restored. Relevant files are likely in the 'packages/markdownviewer' directory. Review the issue comments and any linked PRs for additional context.