Expose 3 new methods with text metrics in RenderParagraph (#65150)

packages/flutter/lib/src/painting/text_painter.dart

@@ -784,7 +784,9 @@ class TextPainter {
     return _caretMetrics.offset;
   }
 
-  /// Returns the tight bounded height of the glyph at the given [position].
+  /// {@template flutter.painting.textPainter.getFullHeightForCaret}
+  /// Returns the strut bounded height of the glyph at the given `position`.
+  /// {@endtemplate}
   ///
   /// Valid only after [layout] has been called.
   double? getFullHeightForCaret(TextPosition position, Rect caretPrototype) {

packages/flutter/lib/src/rendering/paragraph.dart

@@ -744,6 +744,15 @@ class RenderParagraph extends RenderBox
     return _textPainter.getOffsetForCaret(position, caretPrototype);
   }
 
+  /// {@macro flutter.painting.textPainter.getFullHeightForCaret}
+  ///
+  /// Valid only after [layout].
+  double? getFullHeightForCaret(TextPosition position) {
+    assert(!debugNeedsLayout);
+    _layoutTextWithConstraints(constraints);
+    return _textPainter.getFullHeightForCaret(position, Rect.zero);
+  }
+
   /// Returns a list of rects that bound the given selection.
   ///
   /// A given selection might have more than one rect if this text painter

packages/flutter/test/rendering/paragraph_test.dart

@@ -36,6 +36,17 @@ void main() {
     expect(offset50.dy, greaterThan(offset5.dy));
   });
 
+  test('getFullHeightForCaret control test', () {
+    final RenderParagraph paragraph = RenderParagraph(
+      const TextSpan(text: _kText,style: TextStyle(fontSize: 10.0)),
+      textDirection: TextDirection.ltr,
+    );
+    layout(paragraph);
+
+    final double height5 = paragraph.getFullHeightForCaret(const TextPosition(offset: 5));
+    expect(height5, equals(10.0));
+  });
+
   test('getPositionForOffset control test', () {
     final RenderParagraph paragraph = RenderParagraph(
       const TextSpan(text: _kText),