void paint()

in packages/diagrams/lib/src/text.dart [178:308]
109 lines of code
1 McCabe index (conditional complexity)

  void paint(Canvas canvas, Size size) {
    textPainter.layout();

    final List<TextBox> boxes = textPainter.getBoxesForSelection(
        const TextSelection(baseOffset: 0, extentOffset: largeIndex));

    final Paint paint = Paint();
    paint.color = Colors.black;
    paint.strokeWidth = 3.5;
    const double top = 0;
    final double bottom = textPainter.height;
    final double baseline =
        textPainter.computeDistanceToActualBaseline(TextBaseline.alphabetic);

    final double ratio = 100.0 / textPainter.height;
    final double emTop = baseline - (baseline - top) * ratio;
    final double emBottom = baseline + (bottom - baseline) * ratio;

    final double width = boxes[boxes.length - 1].right;
    final Offset baseOffset = Offset(
        (size.width - width) / 2, (size.height - textPainter.height) / 2);

    textPainter.paint(canvas, baseOffset);
    // Baseline
    canvas.drawLine(
      baseOffset + Offset(0, baseline),
      baseOffset + Offset(width, baseline),
      paint,
    );

    paint.color = Colors.blue[900]!;
    // Top
    canvas.drawLine(
      baseOffset,
      baseOffset + Offset(width, top),
      paint,
    );

    // Bottom
    canvas.drawLine(
      baseOffset + Offset(0, bottom),
      baseOffset + Offset(width, bottom),
      paint,
    );

    paint.strokeWidth = 2;
    paint.color = Colors.red[900]!;
    // emTop
    canvas.drawLine(
      baseOffset + Offset(0, emTop),
      baseOffset + Offset(width, emTop),
      paint,
    );

    // emBottom
    canvas.drawLine(
      baseOffset + Offset(0, emBottom),
      baseOffset + Offset(width, emBottom),
      paint,
    );

    paint.strokeWidth = 2;
    paint.style = PaintingStyle.stroke;

    Path path = Path();
    path.moveTo(baseOffset.dx + width + 10, baseOffset.dy + emTop);
    path.lineTo(baseOffset.dx + width + 25, baseOffset.dy + emTop);
    path.lineTo(baseOffset.dx + width + 25, baseOffset.dy + emBottom);
    path.lineTo(baseOffset.dx + width + 10, baseOffset.dy + emBottom);
    canvas.drawPath(path, paint);

    paint.color = Colors.blue[900]!;
    path = Path();
    path.moveTo(baseOffset.dx - 10, baseOffset.dy + top);
    path.lineTo(baseOffset.dx - 25, baseOffset.dy + top);
    path.lineTo(baseOffset.dx - 25, baseOffset.dy + bottom);
    path.lineTo(baseOffset.dx - 10, baseOffset.dy + bottom);
    canvas.drawPath(path, paint);

    const double margin = 8;

    TextPainter label = TextPainter(
      text: const TextSpan(
        text: 'Font metrics\ndefault height',
        style: TextStyle(
          fontSize: 12,
          color: Colors.black,
        ),
      ),
      textAlign: TextAlign.right,
      textDirection: TextDirection.ltr,
    );
    label.layout();
    label.paint(
        canvas,
        baseOffset +
            Offset(-25.0 - (paint.strokeWidth + margin) - label.width,
                (top + bottom) / 2 - 16));

    paint.color = Colors.red[900]!;
    label = TextPainter(
      text: const TextSpan(
        text: 'Font Size\n(EM-square)',
        style: TextStyle(
          fontSize: 12,
          color: Colors.black,
        ),
      ),
      textAlign: TextAlign.left,
      textDirection: TextDirection.ltr,
    );
    label.layout();
    label.paint(canvas,
        baseOffset + Offset(width + 25 + margin, (emTop + emBottom) / 2 - 16));

    paint.color = Colors.black;
    // Baseline label
    label = TextPainter(
      text: const TextSpan(
        text: 'Alphabetic Baseline',
        style: TextStyle(
          fontSize: 11,
          color: Colors.black,
        ),
      ),
      textAlign: TextAlign.left,
      textDirection: TextDirection.ltr,
    );
    label.layout();
    label.paint(canvas, baseOffset + Offset(0, baseline + 3));
  }