// Copyright (c) Six Labors.
// Licensed under the Apache License, Version 2.0.

using SixLabors.ImageSharp.Processing;
using SixLabors.ImageSharp.Processing.Processors.Transforms;

using Xunit;

namespace SixLabors.ImageSharp.Tests.Processing.Processors.Transforms
{
    public class ResamplerTests
    {
        [Theory]
        [InlineData(-2, 0)]
        [InlineData(-1, 0)]
        [InlineData(0, 1)]
        [InlineData(1, 0)]
        [InlineData(2, 0)]
        public static void BicubicWindowOscillatesCorrectly(float x, float expected)
        {
            IResampler sampler = KnownResamplers.Bicubic;
            float result = sampler.GetValue(x);

            Assert.Equal(result, expected);
        }

        [Theory]
        [InlineData(-2, 0)]
        [InlineData(-1, 0)]
        [InlineData(0, 1)]
        [InlineData(1, 0)]
        [InlineData(2, 0)]
        public static void Lanczos3WindowOscillatesCorrectly(float x, float expected)
        {
            IResampler sampler = KnownResamplers.Lanczos3;
            float result = sampler.GetValue(x);

            Assert.Equal(result, expected);
        }

        [Theory]
        [InlineData(-4, 0)]
        [InlineData(-2, 0)]
        [InlineData(0, 1)]
        [InlineData(2, 0)]
        [InlineData(4, 0)]
        public static void Lanczos5WindowOscillatesCorrectly(float x, float expected)
        {
            IResampler sampler = KnownResamplers.Lanczos5;
            float result = sampler.GetValue(x);

            Assert.Equal(result, expected);
        }

        [Theory]
        [InlineData(-2, 0)]
        [InlineData(-1, 0)]
        [InlineData(0, 1)]
        [InlineData(1, 0)]
        [InlineData(2, 0)]
        public static void TriangleWindowOscillatesCorrectly(float x, float expected)
        {
            IResampler sampler = KnownResamplers.Triangle;
            float result = sampler.GetValue(x);

            Assert.Equal(result, expected);
        }
    }
}