computeAlignment static method

double computeAlignment(
  1. int index,
  2. int itemCount
)

Converts an item index to horizontal alignment (-1 to 1).

Used to position the indicator at the correct location for a given item.

Parameters:

  • index: The item index (0-based)
  • itemCount: Total number of items

Returns: Alignment value from -1 (leftmost) to 1 (rightmost).

Example:

// For 3 items (indices 0, 1, 2):
computeAlignment(0, 3) // Returns -1.0 (left)
computeAlignment(1, 3) // Returns  0.0 (center)
computeAlignment(2, 3) // Returns  1.0 (right)

Implementation

static double computeAlignment(int index, int itemCount) {
  final relativeIndex = (index / (itemCount - 1)).clamp(0.0, 1.0);
  return (relativeIndex * 2) - 1;
}