calcMaxLabelWidthWithTransform function

double calcMaxLabelWidthWithTransform(List<String> labels, { required FluentChartTextMeasurer measurer, required TextStyle style, required FluentChartAxisType xAxisType, bool wrapXAxisLabels = false, bool rotateXAxisLabels = false, bool showXAxisLabelsTooltip = false, int noOfCharsToTruncate = 4, })

The widest tick label, measured after whatever transform the axis will apply.

Ports _calcMaxLabelWidthWithTransform (CartesianChart.tsx:576-612). The four branches run in this order and the first match wins: rotated band labels shrink by cos(pi/4); tooltip mode measures the truncated form; wrapping mode measures individual words and floors the answer at kDefaultWrapWidth; otherwise the labels are measured as they are. Every branch ceils.

Implementation

double calcMaxLabelWidthWithTransform(
  List<String> labels, {
  required FluentChartTextMeasurer measurer,
  required TextStyle style,
  required FluentChartAxisType xAxisType,
  bool wrapXAxisLabels = false,
  bool rotateXAxisLabels = false,
  bool showXAxisLabelsTooltip = false,
  int noOfCharsToTruncate = 4,
}) {
  if (!wrapXAxisLabels &&
      rotateXAxisLabels &&
      xAxisType == FluentChartAxisType.category) {
    final longest = measurer.longestWidth(labels, style);
    return (longest * math.cos(math.pi / 4)).ceilToDouble();
  }

  if (showXAxisLabelsTooltip) {
    final truncated = <String>[
      // CartesianChart.tsx:587 compares the whole length against the budget, so
      // a label of exactly noOfCharsToTruncate code units is left alone.
      for (final label in labels)
        if (label.length > noOfCharsToTruncate)
          '${label.substring(0, noOfCharsToTruncate)}...'
        else
          label,
    ];
    return measurer.longestWidth(truncated, style).ceilToDouble();
  }

  if (wrapXAxisLabels) {
    // FIXME upstream: CartesianChart.tsx:596-597 notes this measures words
    // rather than wrapped lines, which is close enough because overflow only
    // happens when a single word exceeds the width.
    final words = <String>[
      for (final label in labels) ...label.split(RegExp(r'\s+')),
    ];
    return math.max(
      measurer.longestWidth(words, style).ceilToDouble(),
      kDefaultWrapWidth,
    );
  }

  return measurer.longestWidth(labels, style).ceilToDouble();
}