fix: TextBoxComponent crashes with the text in the examples #3938

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1. erickzanardo

   added

   bug

   on Jul 1, 2026
2. erickzanardo

   self-assigned this

   on Jul 1, 2026
3. erickzanardo commented on Jul 1, 2026

   

   erickzanardo

   on Jul 1, 2026

   MemberAuthor

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   After a bit of debugging, I tracked down the freezing to this method in the text_box_component.dart file:

     void _updateBoundsWithTextPainter(double availableWidth) {
       final textPaint = textRenderer as TextPaint;
       final textPainter = textPaint.toTextPainter(text);
       textPainter.layout(maxWidth: availableWidth);
   
       // Extract lines from the laid out text using line boundaries
       final lineMetricsList = textPainter.computeLineMetrics();
       var lineHeight = 0.0;
       var offset = 0;
   
       while (offset < text.length) { // CODE NEVER LEAVES THIS WHILE
         final range = textPainter.getLineBoundary(TextPosition(offset: offset));
         var lineText = text.substring(range.start, range.end);
   
         // Don't include the trailing newline character in the line text
         if (lineText.endsWith('\n')) {
           lineText = lineText.substring(0, lineText.length - 1);
         }
   
         lines.add(lineText);
   
         // Update max width based on actual line width
         final actualLineMetrics = textRenderer.getLineMetrics(lineText);
         _updateMaxWidth(actualLineMetrics.width);
   
         // Move to the next line
         offset = range.end;
         if (offset < text.length && text[offset] == '\n') {
           offset++; // Skip the newline character
         }
       }
   
       // Get line height from the metrics
       if (lineMetricsList.isNotEmpty) {
         lineHeight = lineMetricsList.first.height;
       }
   
       _lineHeight = lineHeight;
       _totalLines = lines.length;
     }

   I also discovered that it is not only that text that causes the issue, this also does: AAA AA AAA A A A.

   I am confidente that the issue is because of the classic JS number rouding issues, but I am still debugging.
4. erickzanardo

   closed this as completedin #3939on Jul 1, 2026