Function normalizePanelCellSizes

packages/core/src/widgets/splitPane.ts:25–81

(
  sizes: number[],
  availableForPanels: number,
  minSizes?: readonly number[],
  maxSizes?: readonly number[],
)

}>;

function normalizePanelCellSizes(
  sizes: number[],
  availableForPanels: number,
  minSizes?: readonly number[],
  maxSizes?: readonly number[],
): void {
  // Apply min/max constraints
  for (let i = 0; i < sizes.length; i++) {
    const minSize = minSizes?.[i] ?? 0;
    const maxSize = maxSizes?.[i] ?? availableForPanels;
    const size = sizes[i] ?? 0;
    sizes[i] = Math.max(minSize, Math.min(maxSize, size));
  }

  // Distribute remainder / shrink overshoot to fit available space
  const totalSize = sizes.reduce((a, b) => a + (b ?? 0), 0);
  const remainder = availableForPanels - totalSize;
  if (remainder > 0) {
    let r = remainder;
    while (r > 0) {
      let progressed = false;
      for (let i = 0; i < sizes.length && r > 0; i++) {
        const currentSize = sizes[i] ?? 0;
        const maxSize = maxSizes?.[i] ?? availableForPanels;
        if (currentSize < maxSize) {
          sizes[i] = currentSize + 1;
          r--;
          progressed = true;
        }
      }
      if (!progressed) break;
    }
  } else if (remainder < 0) {
    let overshoot = -remainder;

    // First pass: shrink but respect minSizes.
    for (let i = sizes.length - 1; i >= 0 && overshoot > 0; i--) {
      const currentSize = sizes[i] ?? 0;
      const minSize = minSizes?.[i] ?? 0;
      const canReduce = Math.max(0, currentSize - minSize);
      if (canReduce === 0) continue;
      const delta = Math.min(overshoot, canReduce);
      sizes[i] = currentSize - delta;
      overshoot -= delta;
    }

    // Second pass: if constraints are impossible (sum(minSizes) > available), shrink below mins down to 0.
    for (let i = sizes.length - 1; i >= 0 && overshoot > 0; i--) {
      const currentSize = sizes[i] ?? 0;
      const canReduce = Math.max(0, currentSize);
      if (canReduce === 0) continue;
      const delta = Math.min(overshoot, canReduce);
      sizes[i] = currentSize - delta;
      overshoot -= delta;
    }
  }
}