Harmony XElement Notes

markdown

Harmony markdown should follow the native XElement integration path:

• markdown is registered from the native XElement registry. Keep <markdown> as the public tag under lynx/; internal x-markdown belongs outside the open-source boundary.
• Layout and rendering are implemented by C++ UIBase and ShadowNode classes through C UI/ArkUI native nodes.
• The core @lynx/lynx package must not depend on @lynx/serval_markdown or @lynx/lynxtextra. The native registry should resolve markdown creators from the @lynx/xelement_markdown native library through dlopen / dlsym.
• @lynx/xelement_markdown must call its native initMarkdown() before Lynx views using markdown are created. This loads liblynx_xelement_markdown.so and registers the direct creators.
• For Harmony arm64 and x86_64 builds, @lynx/xelement_markdown links against the C++ symbols exported by the @lynx/serval_markdown OHPM package.
• This path does not build or load the internal liblynx_markdown.so package.

Do not implement markdown as an ArkTS UIBase wrapper around @lynx/serval_markdown. Serval markdown can provide the markdown parsing, layout, and drawing core, but the Lynx XElement integration should stay native.

@lynx/serval_markdown must expose the C++ view-layer symbols used by the native XElement, including NativeServalMarkdownView and MarkdownView. Shadow layout should measure through MarkdownView::Measure() rather than depending on internal serval measurer classes.