ImageSharp/tests/ImageSharp.Tests/Drawing/DrawPathTests.cs

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

using System.IO;
using System.Numerics;
using SixLabors.ImageSharp.Drawing.Pens;
using SixLabors.ImageSharp.PixelFormats;
using SixLabors.Shapes;
using Xunit;
using ShapePath = SixLabors.Shapes.Path;

namespace SixLabors.ImageSharp.Tests.Drawing
{
    using SixLabors.ImageSharp.Processing;
    using SixLabors.ImageSharp.Processing.Overlays;

    public class DrawPathTests : FileTestBase
    {
        [Fact]
        public void ImageShouldBeOverlayedByPath()
        {
            string path = TestEnvironment.CreateOutputDirectory("Drawing", "Path");
            using (Image<Rgba32> image = new Image<Rgba32>(500, 500))
            {
                LinearLineSegment linerSegemnt = new LinearLineSegment(
                    new Vector2(10, 10),
                    new Vector2(200, 150),
                    new Vector2(50, 300));
                CubicBezierLineSegment bazierSegment = new CubicBezierLineSegment(new Vector2(50, 300),
                    new Vector2(500, 500),
                    new Vector2(60, 10),
                    new Vector2(10, 400));

                ShapePath p = new ShapePath(linerSegemnt, bazierSegment);

                image.Mutate(x => x
                    .BackgroundColor(Rgba32.Blue)
                    .Draw(Rgba32.HotPink, 5, p));
                image.Save($"{path}/Simple.png");

                using (PixelAccessor<Rgba32> sourcePixels = image.Lock())
                {
                    Assert.Equal(Rgba32.HotPink, sourcePixels[11, 11]);

                    Assert.Equal(Rgba32.HotPink, sourcePixels[199, 149]);

                    Assert.Equal(Rgba32.Blue, sourcePixels[50, 50]);
                }
            }
        }


        [Fact]
        public void ImageShouldBeOverlayedPathWithOpacity()
        {
            string path = TestEnvironment.CreateOutputDirectory("Drawing", "Path");

            Rgba32 color = new Rgba32(Rgba32.HotPink.R, Rgba32.HotPink.G, Rgba32.HotPink.B, 150);


            LinearLineSegment linerSegemnt = new LinearLineSegment(
                            new Vector2(10, 10),
                            new Vector2(200, 150),
                            new Vector2(50, 300)
                    );

            CubicBezierLineSegment bazierSegment = new CubicBezierLineSegment(new Vector2(50, 300),
                new Vector2(500, 500),
                new Vector2(60, 10),
                new Vector2(10, 400));

            ShapePath p = new ShapePath(linerSegemnt, bazierSegment);

            using (Image<Rgba32> image = new Image<Rgba32>(500, 500))
            {
                image.Mutate(x => x
                    .BackgroundColor(Rgba32.Blue)
                    .Draw(color, 10, p));
                image.Save($"{path}/Opacity.png");

                //shift background color towards forground color by the opacity amount
                Rgba32 mergedColor = new Rgba32(Vector4.Lerp(Rgba32.Blue.ToVector4(), Rgba32.HotPink.ToVector4(), 150f / 255f));

                using (PixelAccessor<Rgba32> sourcePixels = image.Lock())
                {
                    Assert.Equal(mergedColor, sourcePixels[11, 11]);

                    Assert.Equal(mergedColor, sourcePixels[199, 149]);

                    Assert.Equal(Rgba32.Blue, sourcePixels[50, 50]);
                }
            }
        }


        [Fact]
        public void PathExtendingOffEdgeOfImageShouldNotBeCropped()
        {

            string path = TestEnvironment.CreateOutputDirectory("Drawing", "Path");
            using (var image = new Image<Rgba32>(256, 256))
            {
                image.Mutate(x => x.Fill(Rgba32.Black));
                var pen = Pens.Solid(Rgba32.White, 5f);

                for (int i = 0; i < 300; i += 20)
                {
                    image.Mutate(x => x.DrawLines(pen, new SixLabors.Primitives.PointF[] { new Vector2(100, 2), new Vector2(-10, i) }));
                }

                image
                    .Save($"{path}/ClippedLines.png");
                using (PixelAccessor<Rgba32> sourcePixels = image.Lock())
                {
                    Assert.Equal(Rgba32.White, sourcePixels[0, 90]);
                }
            }
        }
    }
}