isPointerNearDeleteArea function
Implementation
bool isPointerNearDeleteArea({
required Offset pointerOffset,
required Offset deleteAreaOffset,
required double threshold,
}) {
// 2つのオフセット間の距離を計算
final distance = (pointerOffset - deleteAreaOffset).distance;
// 距離が閾値以下であれば true を返す
return distance <= threshold;
}