Function extract_text 

pub fn extract_text(main: &mut World, render: &mut World)

Default extract fn that emits one ExtractedText per entity with Transform and TextContent.

• When an ImeState is present, its preedit is concatenated onto the committed text.
• For focused <input> entities, caret offset and selection range are propagated.
• Under a concealed EchoMode the display glyphs, caret, and selection are masked (see [mask_echo]); the buffer plaintext is untouched.
• Hidden subtrees and entities clipped fully outside their scroll/overflow ancestor are skipped.