rotatedTextSize function

Rect rotatedTextSize(Size size, int angle)

This method returns the rect for given size and angle

Implementation

Rect rotatedTextSize(Size size, int angle) {
  final Rect rect = Rect.fromLTWH(0, 0, size.width, size.height);
  final vector.Matrix2 rotatorMatrix = vector.Matrix2.rotation(
    degreeToRadian(angle),
  );

  final Rect movedToCenterAsOrigin = rect.shift(-rect.center);

  Offset topLeft = movedToCenterAsOrigin.topLeft;
  Offset topRight = movedToCenterAsOrigin.topRight;
  Offset bottomLeft = movedToCenterAsOrigin.bottomLeft;
  Offset bottomRight = movedToCenterAsOrigin.bottomRight;

  topLeft = transform(rotatorMatrix, topLeft);
  topRight = transform(rotatorMatrix, topRight);
  bottomLeft = transform(rotatorMatrix, bottomLeft);
  bottomRight = transform(rotatorMatrix, bottomRight);

  final List<Offset> rotOffsets = <Offset>[
    topLeft,
    topRight,
    bottomLeft,
    bottomRight,
  ];

  final double minX = rotOffsets
      .map((Offset offset) => offset.dx)
      .reduce(math.min);
  final double maxX = rotOffsets
      .map((Offset offset) => offset.dx)
      .reduce(math.max);
  final double minY = rotOffsets
      .map((Offset offset) => offset.dy)
      .reduce(math.min);
  final double maxY = rotOffsets
      .map((Offset offset) => offset.dy)
      .reduce(math.max);

  final Rect rotateRect = Rect.fromPoints(
    Offset(minX, minY),
    Offset(maxX, maxY),
  );
  return rotateRect;
}