fix cursorheight issue

com.unity.uiwidgets/Runtime/painting/text_painter.cs

@@ -56,6 +56,7 @@ public class TextPainter {
         TextDirection? _textDirection;
         float _textScaleFactor;
         Paragraph _layoutTemplate;
+        Paragraph _layoutCursorTemplate;
         Paragraph _paragraph;
         bool _needsLayout = true;
         int? _maxLines;
@@ -106,6 +107,7 @@ public float textScaleFactor {
                 _textScaleFactor = value;
                 markNeedsLayout();
                 _layoutTemplate = null;
+                _layoutCursorTemplate = null;
             }
         }
 
@@ -131,6 +133,7 @@ public InlineSpan text {
 
                 if (!Equals(_text == null ? null : _text.style, value == null ? null : value.style)) {
                     _layoutTemplate = null;
+                    _layoutCursorTemplate = null;
                 }
 
                 _text = value;
@@ -155,6 +158,7 @@ public TextDirection? textDirection {
                 _textDirection = value;
                 markNeedsLayout();
                 _layoutTemplate = null;
+                _layoutCursorTemplate = null;
             }
         }
 
@@ -451,6 +455,45 @@ ParagraphStyle _createParagraphStyle(TextDirection defaultTextDirection = TextDi
             );
         }
 
+        ParagraphStyle _createParagraphStyleWithNoStrutStyle(TextDirection defaultTextDirection = TextDirection.ltr) {
+            D.assert(textDirection != null,
+                () => "TextPainter.textDirection must be set to a non-null value before using the TextPainter.");
+            return _text.style?.getParagraphStyle(
+                textAlign: textAlign,
+                textDirection: textDirection ?? defaultTextDirection,
+                textScaleFactor: textScaleFactor,
+                maxLines: _maxLines,
+                textHeightBehavior: _textHeightBehavior,
+                ellipsis: _ellipsis,
+                locale: _locale
+            ) ?? new ParagraphStyle(
+                textAlign: textAlign,
+                textDirection: textDirection ?? defaultTextDirection,
+                maxLines: maxLines,
+                textHeightBehavior: _textHeightBehavior,
+                ellipsis: ellipsis,
+                locale: locale
+            );
+        }
+
+        public float preferredCursorHeight {
+            get {
+                if (_layoutCursorTemplate == null) {
+                    var builder = new ParagraphBuilder(_createParagraphStyleWithNoStrutStyle(TextDirection.ltr)
+                    ); // direction doesn't matter, text is just a space
+                    if (text != null && text.style != null) {
+                        builder.pushStyle(text.style.getTextStyle(textScaleFactor: textScaleFactor));
+                    }
+
+                    builder.addText(" ");
+                    _layoutCursorTemplate = builder.build();
+                    _layoutCursorTemplate.layout(new ParagraphConstraints(float.PositiveInfinity));
+                }
+
+                return _layoutCursorTemplate.height();
+            }
+        }
+
         public float preferredLineHeight {
             get {
                 if (_layoutTemplate == null) {

com.unity.uiwidgets/Runtime/rendering/editable.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Text;
 using Unity.UIWidgets.async;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.gestures;
@@ -385,16 +386,18 @@ void _handleSelectionChange(
             TextSelection nextSelection,
             SelectionChangedCause cause
         ) {
-
-            bool focusingEmpty = nextSelection.baseOffset == 0
-                                       && nextSelection.extentOffset == 0
-                                       && !hasFocus;
+            //force to update selection no matter whether the selection really changes
+            //it should not affect the ui logics except some performance drop
+            /*bool focusingEmpty = nextSelection.baseOffset == 0
+                                 && nextSelection.extentOffset == 0
+                                 && !hasFocus;
             if (nextSelection == selection
                 && cause != SelectionChangedCause.keyboard
                 && !focusingEmpty) {
+                Debug.Log("[ZXW2] handle double tap6 <>>>");
                 return;
-            }
-
+            }*/
+            
             onSelectionChanged?.Invoke(nextSelection, this, cause);
         }
 
@@ -1290,6 +1293,10 @@ public float preferredLineHeight {
             get { return _textPainter.preferredLineHeight; }
         }
 
+        private float preferredCursorHeight {
+            get { return _textPainter.preferredCursorHeight; }
+        }
+
         float _preferredHeight(float width) {
             bool lockedMax = maxLines != null && minLines == null;
             bool lockedBoth = maxLines != null && minLines == maxLines;
@@ -1454,7 +1461,7 @@ public void selectWordsInRange(Offset from = null, Offset to = null, SelectionCh
                 ? firstWord
                 : _selectWordAtOffset(
                     _textPainter.getPositionForOffset(globalToLocal(to - _paintOffset)));
-
+            
             _handleSelectionChange(
                 new TextSelection(
                     baseOffset: firstWord.baseOffset,
@@ -1537,14 +1544,26 @@ Rect _getCaretPrototype {
                 switch (Application.platform) {
                     case RuntimePlatform.IPhonePlayer:
                         return Rect.fromLTWH(0.0f, 0.0f, cursorWidth,
-                            preferredLineHeight + 2.0f);
+                            preferredCursorHeight + 2.0f);
                     default:
-                        return Rect.fromLTWH(0.0f, EditableUtils._kCaretHeightOffset, cursorWidth,
-                            preferredLineHeight - 2.0f * EditableUtils._kCaretHeightOffset);
+                        return Rect.fromLTWH(0.0f, 0.0f, cursorWidth,
+                            preferredCursorHeight);
+                }
+            }
+        }
+
+        Rect _getCaretPrototypeForEmptyLine {
+            get {
+                switch (Application.platform) {
+                    case RuntimePlatform.IPhonePlayer:
+                        return Rect.fromLTWH(0.0f, (preferredLineHeight - preferredCursorHeight) / 2, cursorWidth,
+                            preferredCursorHeight + 2.0f);
+                    default:
+                        return Rect.fromLTWH(0.0f, (preferredLineHeight - preferredCursorHeight) / 2, cursorWidth,
+                            preferredCursorHeight);
                 }
             }
         }
-
 
         protected override void performLayout() {
             BoxConstraints constraints = this.constraints;
@@ -1577,13 +1596,37 @@ void _paintCaret(Canvas canvas, Offset effectiveOffset, TextPosition textPositio
                    _textLayoutLastMinWidth == constraints.minWidth,
                 () => $"Last width ({_textLayoutLastMinWidth}, {_textLayoutLastMaxWidth}) not the same as max width constraint ({constraints.minWidth}, {constraints.maxWidth}).");
             var paint = new Paint() {color = _floatingCursorOn ? backgroundCursorColor : _cursorColor};
-            var caretOffset = _textPainter.getOffsetForCaret(textPosition, _caretPrototype) + effectiveOffset;
-            Rect caretRect = _caretPrototype.shift(caretOffset);
+
+            //force offset to 0 (at the beginning of the text if the text is currently focused
+            if (hasFocus && textPosition.offset == -1)
+            {
+                textPosition = new TextPosition(0, textPosition.affinity);
+            }
+            //if there is no contents in this editable yet, we use the _getCaretPrototypeForEmptyLine API to fetch the proper caret height
+            var currentCaretPrototype = _caretPrototype;
+            var content = new StringBuilder();
+            text.computeToPlainText(content, false, false);
+
+            //Debug.Log("[ZXW] text is " + content.ToString());
+            if (string.IsNullOrEmpty(content.ToString())) {
+                currentCaretPrototype = _getCaretPrototypeForEmptyLine;
+            }
+
+            //Debug.Log("[ZXW] caret offset is " + currentCaretPrototype.top + " " + _caretPrototype.top + " " + _getCaretPrototypeForEmptyLine.top);
+
+
+            var caretOffset = _textPainter.getOffsetForCaret(textPosition, currentCaretPrototype) + effectiveOffset;
+
+            Rect caretRect = currentCaretPrototype.shift(caretOffset);
+
+            //Debug.Log("[ZXW] caretRect is " + effectiveOffset.dy + " " + caretOffset.dy + " " + caretRect.top);
+
+
             if (_cursorOffset != null) {
                 caretRect = caretRect.shift(_cursorOffset);
+                //Debug.Log("[ZXW] caretRect shift " + _cursorOffset.dy + " " + caretRect.top);
             }
-
-            float? caretHeight = _textPainter.getFullHeightForCaret(textPosition, _caretPrototype);
+            float? caretHeight = _textPainter.getFullHeightForCaret(textPosition, currentCaretPrototype);
             if (caretHeight != null) {
                 switch (Application.platform) {
                     case RuntimePlatform.IPhonePlayer:
@@ -1598,16 +1641,20 @@ void _paintCaret(Canvas canvas, Offset effectiveOffset, TextPosition textPositio
                     default:
                         caretRect = Rect.fromLTWH(
                             caretRect.left,
-                            caretRect.top - EditableUtils._kCaretHeightOffset,
+                            caretRect.top,
                             caretRect.width,
                             caretHeight.Value
                         );
+
+                        //Debug.Log("[ZXW] caretRect final " + caretRect.height + " " + caretRect.top);
                         break;
                 }
             }
 
             caretRect = caretRect.shift(_getPixelPerfectCursorOffset(caretRect));
-
+
+            //Debug.Log("[ZXW] caretRect pixel perfect " + caretRect.height + " " + caretRect.top);
+
             if (cursorRadius == null) {
                 canvas.drawRect(caretRect, paint);
             }