lib/ui/lerp.dart

// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// @dart = 2.6
part of dart.ui;

/// Linearly interpolate between two numbers.
double/*!*/ lerpDouble(num/*?*/ a, num/*?*/ b, double/*!*/ t) {
  if (a == null && b == null)
    return null;
  a ??= 0.0;
  b ??= 0.0;
  return a + (b - a) * t as double;
}

/// Linearly interpolate between two doubles.
///
/// Same as [lerpDouble] but specialized for non-null `double` type.
double/*!*/ _lerpDouble(double/*!*/ a, double/*!*/ b, double/*!*/ t) {
  return a + (b - a) * t;
}

/// Linearly interpolate between two integers.
///
/// Same as [lerpDouble] but specialized for non-null `int` type.
double/*!*/ _lerpInt(int/*!*/ a, int/*!*/ b, double/*!*/ t) {
  return a + (b - a) * t;
}

/// Same as [num.clamp] but specialized for non-null [int].
int/*!*/ _clampInt(int/*!*/ value, int/*!*/ min, int/*!*/ max) {
  assert(min <= max);
  if (value < min) {
    return min;
  } else if (value > max) {
    return max;
  } else {
    return value;
  }
}