Multi-box text selections in RenderEditor

[user97116]

Summary

RenderEditor currently doesn’t support multiple selection boxes like RenderParagraph.getBoxesForSelection().
Developers need a way to access all selection boxes to properly render custom highlights, comments, or decorations when text spans multiple lines or blocks.

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Expected Behavior

A method like:

List<TextBox> getBoxesForSelection(TextSelection selection);

should return a list of TextBox objects for each segment of the selection.
This would allow precise drawing of highlights or overlays across lines and embedded blocks.

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Actual Behavior

Only a single bounding box is available.
Selections spanning multiple lines or nodes can’t be accurately highlighted or decorated.

Example:

final boxes = renderEditor.getBoxesForSelection(selection); // Not available

No public API provides these boxes currently.

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Why It’s Needed

• Enables accurate multi-line highlight rendering (like Google Docs).
• Helps build annotation/comment UI with correct geometry.
• Improves selection UX consistency with Flutter’s native text engine (RenderParagraph.getBoxesForSelection).

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Environment

Item	Version
Flutter Quill	^11.4.2
Flutter	3.35.6
Dart	3.9.2
Platform	Android / iOS / Web / Desktop

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Additional Context

This would make it easier to implement advanced text selection visuals and editing behaviors, especially for collaborative or document-style editors.