Replace System.Drawing.Common with SkiaSharp (#455)

Algorithms.Tests/Other/FloodFillTest.cs

@@ -1,17 +1,18 @@
-using System;
-using System.Drawing;
 using FluentAssertions;
 using NUnit.Framework;
+using SkiaSharp;
+using System;
 
 namespace Algorithms.Tests.Other;
 
 public static class Tests
 {
- private static readonly Color Black = Color.FromArgb(255, 0, 0, 0);
- private static readonly Color Green = Color.FromArgb(255, 0, 255, 0);
- private static readonly Color Violet = Color.FromArgb(255, 255, 0, 255);
- private static readonly Color White = Color.FromArgb(255, 255, 255, 255);
- private static readonly Color Orange = Color.FromArgb(255, 255, 128, 0);
+ private const byte Alpha = 255;
+ private static readonly SKColor Black = new(0, 0, 0, Alpha);
+ private static readonly SKColor Green = new(0, 255, 0, Alpha);
+ private static readonly SKColor Violet = new(255, 0, 255, Alpha);
+ private static readonly SKColor White = new(255, 255, 255, Alpha);
+ private static readonly SKColor Orange = new(255, 128, 0, Alpha);
 
  [Test]
  public static void BreadthFirstSearch_ThrowsArgumentOutOfRangeException()
@@ -63,9 +64,9 @@ public static void DepthFirstSearch_Test3()
  TestAlgorithm(Algorithms.Other.FloodFill.DepthFirstSearch, (1, 1), Green, Orange, (6, 4), White);
  }
 
- private static Bitmap GenerateTestBitmap()
+ private static SKBitmap GenerateTestBitmap()
  {
- Color[,] layout =
+ SKColor[,] layout =
  {
  {Violet, Violet, Green, Green, Black, Green, Green},
  {Violet, Green, Green, Black, Green, Green, Green},
@@ -76,7 +77,7 @@ private static Bitmap GenerateTestBitmap()
  {Violet, Violet, Violet, Violet, Violet, Violet, Violet},
  };
 
- Bitmap bitmap = new(7, 7);
+ SKBitmap bitmap = new(7, 7);
  for (int x = 0; x < layout.GetLength(0); x++)
  {
  for (int y = 0; y < layout.GetLength(1); y++)
@@ -89,16 +90,16 @@ private static Bitmap GenerateTestBitmap()
  }
 
  private static void TestAlgorithm(
- Action<Bitmap, ValueTuple<int, int>, Color, Color> algorithm,
+ Action<SKBitmap, ValueTuple<int, int>, SKColor, SKColor> algorithm,
  ValueTuple<int, int> fillLocation,
- Color targetColor,
- Color replacementColor,
+ SKColor targetColor,
+ SKColor replacementColor,
  ValueTuple<int, int> testLocation,
- Color expectedColor)
+ SKColor expectedColor)
  {
- Bitmap bitmap = GenerateTestBitmap();
+ SKBitmap bitmap = GenerateTestBitmap();
  algorithm(bitmap, fillLocation, targetColor, replacementColor);
- Color actualColor = bitmap.GetPixel(testLocation.Item1, testLocation.Item2);
+ SKColor actualColor = bitmap.GetPixel(testLocation.Item1, testLocation.Item2);
  actualColor.Should().Be(expectedColor);
  }
 }

Algorithms.Tests/Other/KochSnowflakeTest.cs

@@ -1,10 +1,10 @@
-using System;
-using System.Collections.Generic;
-using System.Drawing;
-using System.Numerics;
 using Algorithms.Other;
 using FluentAssertions;
 using NUnit.Framework;
+using SkiaSharp;
+using System;
+using System.Collections.Generic;
+using System.Numerics;
 
 namespace Algorithms.Tests.Other;
 
@@ -39,13 +39,12 @@ public static void TestKochSnowflakeExample()
  var bitmapWidth = 600;
  var offsetX = bitmapWidth / 10f;
  var offsetY = bitmapWidth / 3.7f;
-
- Bitmap bitmap = KochSnowflake.GetKochSnowflake();
+ SKBitmap bitmap = KochSnowflake.GetKochSnowflake();
  bitmap.GetPixel(0, 0)
  .Should()
- .Be(Color.FromArgb(255, 255, 255, 255), "because the background should be white");
+ .Be(new SKColor(255, 255, 255, 255), "because the background should be white");
  bitmap.GetPixel((int)offsetX, (int)offsetY)
  .Should()
- .Be(Color.FromArgb(255, 0, 0, 0), "because the snowflake is drawn in black and this is the position of the first vector");
+ .Be(new SKColor(0, 0, 0, 255), "because the snowflake is drawn in black and this is the position of the first vector");
  }
 }

Algorithms.Tests/Other/MandelbrotTest.cs

@@ -1,7 +1,7 @@
 using System;
-using System.Drawing;
 using Algorithms.Other;
 using NUnit.Framework;
+using SkiaSharp;
 
 namespace Algorithms.Tests.Other;
 
@@ -28,22 +28,22 @@ public static void MaxStepIsZeroOrNegative_ThrowsArgumentOutOfRangeException()
  [Test]
  public static void TestBlackAndWhite()
  {
- Bitmap bitmap = Mandelbrot.GetBitmap(useDistanceColorCoding: false);
+ SKBitmap bitmap = Mandelbrot.GetBitmap(useDistanceColorCoding: false);
  // Pixel outside the Mandelbrot set should be white.
- Assert.That(Color.FromArgb(255, 255, 255, 255), Is.EqualTo(bitmap.GetPixel(0, 0)));
+ Assert.That(new SKColor(255, 255, 255, 255), Is.EqualTo(bitmap.GetPixel(0, 0)));
 
  // Pixel inside the Mandelbrot set should be black.
- Assert.That(Color.FromArgb(255, 0, 0, 0), Is.EqualTo(bitmap.GetPixel(400, 300)));
+ Assert.That(new SKColor(0, 0, 0, 255), Is.EqualTo(bitmap.GetPixel(400, 300)));
  }
 
  [Test]
  public static void TestColorCoded()
  {
- Bitmap bitmap = Mandelbrot.GetBitmap(useDistanceColorCoding: true);
+ SKBitmap bitmap = Mandelbrot.GetBitmap(useDistanceColorCoding: true);
  // Pixel distant to the Mandelbrot set should be red.
- Assert.That(Color.FromArgb(255, 255, 0, 0), Is.EqualTo(bitmap.GetPixel(0, 0)));
+ Assert.That(new SKColor(255, 0, 0, 255), Is.EqualTo(bitmap.GetPixel(0, 0)));
 
  // Pixel inside the Mandelbrot set should be black.
- Assert.That(Color.FromArgb(255, 0, 0, 0), Is.EqualTo(bitmap.GetPixel(400, 300)));
+ Assert.That(new SKColor(0, 0, 0, 255), Is.EqualTo(bitmap.GetPixel(400, 300)));
  }
 }

Algorithms/Algorithms.csproj

@@ -16,11 +16,12 @@
  </ItemGroup>
 
  <ItemGroup>
+ <PackageReference Include="SkiaSharp" Version="2.88.8" />
+ <PackageReference Include="SkiaSharp.NativeAssets.Linux.NoDependencies" Version="2.88.8" />
  <PackageReference Include="StyleCop.Analyzers" Version="1.1.118">
  <PrivateAssets>all</PrivateAssets>
  <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
  </PackageReference>
- <PackageReference Include="System.Drawing.Common" Version="5.0.3" />
  </ItemGroup>
 
  <ItemGroup>

Algorithms/Other/FloodFill.cs

@@ -1,6 +1,6 @@
 using System;
 using System.Collections.Generic;
-using System.Drawing;
+using SkiaSharp;
 
 namespace Algorithms.Other;
 
@@ -23,7 +23,7 @@ public static class FloodFill
  /// <param name="location">The start location on the bitmap.</param>
  /// <param name="targetColor">The old color to be replaced.</param>
  /// <param name="replacementColor">The new color to replace the old one.</param>
- public static void BreadthFirstSearch(Bitmap bitmap, (int x, int y) location, Color targetColor, Color replacementColor)
+ public static void BreadthFirstSearch(SKBitmap bitmap, (int x, int y) location, SKColor targetColor, SKColor replacementColor)
  {
  if (location.x < 0 || location.x >= bitmap.Width || location.y < 0 || location.y >= bitmap.Height)
  {
@@ -46,7 +46,7 @@ public static void BreadthFirstSearch(Bitmap bitmap, (int x, int y) location, Co
  /// <param name="location">The start location on the bitmap.</param>
  /// <param name="targetColor">The old color to be replaced.</param>
  /// <param name="replacementColor">The new color to replace the old one.</param>
- public static void DepthFirstSearch(Bitmap bitmap, (int x, int y) location, Color targetColor, Color replacementColor)
+ public static void DepthFirstSearch(SKBitmap bitmap, (int x, int y) location, SKColor targetColor, SKColor replacementColor)
  {
  if (location.x < 0 || location.x >= bitmap.Width || location.y < 0 || location.y >= bitmap.Height)
  {
@@ -56,7 +56,7 @@ public static void DepthFirstSearch(Bitmap bitmap, (int x, int y) location, Colo
  DepthFirstFill(bitmap, location, targetColor, replacementColor);
  }
 
- private static void BreadthFirstFill(Bitmap bitmap, (int x, int y) location, Color targetColor, Color replacementColor, List<(int x, int y)> queue)
+ private static void BreadthFirstFill(SKBitmap bitmap, (int x, int y) location, SKColor targetColor, SKColor replacementColor, List<(int x, int y)> queue)
  {
  (int x, int y) currentLocation = queue[0];
  queue.RemoveAt(0);
@@ -77,7 +77,7 @@ private static void BreadthFirstFill(Bitmap bitmap, (int x, int y) location, Col
  }
  }
 
- private static void DepthFirstFill(Bitmap bitmap, (int x, int y) location, Color targetColor, Color replacementColor)
+ private static void DepthFirstFill(SKBitmap bitmap, (int x, int y) location, SKColor targetColor, SKColor replacementColor)
  {
  if (bitmap.GetPixel(location.x, location.y) == targetColor)
  {

Algorithms/Other/KochSnowflake.cs

@@ -1,7 +1,7 @@
 using System;
 using System.Collections.Generic;
-using System.Drawing;
 using System.Numerics;
+using SkiaSharp;
 
 namespace Algorithms.Other;
 
@@ -52,7 +52,7 @@ public static List<Vector2> Iterate(List<Vector2> initialVectors, int steps = 5)
  /// <param name="bitmapWidth">The width of the rendered bitmap.</param>
  /// <param name="steps">The number of iterations.</param>
  /// <returns>The bitmap of the rendered Koch snowflake.</returns>
- public static Bitmap GetKochSnowflake(
+ public static SKBitmap GetKochSnowflake(
  int bitmapWidth = 600,
  int steps = 5)
  {
@@ -124,31 +124,36 @@ private static Vector2 Rotate(Vector2 vector, float angleInDegrees)
  /// <param name="bitmapWidth">The width of the rendered bitmap.</param>
  /// <param name="bitmapHeight">The height of the rendered bitmap.</param>
  /// <returns>The bitmap of the rendered edges.</returns>
- private static Bitmap GetBitmap(
+ private static SKBitmap GetBitmap(
  List<Vector2> vectors,
  int bitmapWidth,
  int bitmapHeight)
  {
- Bitmap bitmap = new(bitmapWidth, bitmapHeight);
+ SKBitmap bitmap = new(bitmapWidth, bitmapHeight);
+ var canvas = new SKCanvas(bitmap);
 
- using (Graphics graphics = Graphics.FromImage(bitmap))
+ // Set the background white
+ var rect = SKRect.Create(0, 0, bitmapWidth, bitmapHeight);
+
+ var paint = new SKPaint
  {
- // Set the background white
- var imageSize = new Rectangle(0, 0, bitmapWidth, bitmapHeight);
- graphics.FillRectangle(Brushes.White, imageSize);
-
- // Draw the edges
- for (var i = 0; i < vectors.Count - 1; i++)
- {
- Pen blackPen = new(Color.Black, 1);
-
- var x1 = vectors[i].X;
- var y1 = vectors[i].Y;
- var x2 = vectors[i + 1].X;
- var y2 = vectors[i + 1].Y;
-
- graphics.DrawLine(blackPen, x1, y1, x2, y2);
- }
+ Style = SKPaintStyle.Fill,
+ Color = SKColors.White,
+ };
+
+ canvas.DrawRect(rect, paint);
+
+ paint.Color = SKColors.Black;
+
+ // Draw the edges
+ for (var i = 0; i < vectors.Count - 1; i++)
+ {
+ var x1 = vectors[i].X;
+ var y1 = vectors[i].Y;
+ var x2 = vectors[i + 1].X;
+ var y2 = vectors[i + 1].Y;
+
+ canvas.DrawLine(new SKPoint(x1, y1), new SKPoint(x2, y2), paint);
  }
 
  return bitmap;

Algorithms/Other/Mandelbrot.cs

@@ -1,5 +1,5 @@
 using System;
-using System.Drawing;
+using SkiaSharp;
 
 namespace Algorithms.Other;
 
@@ -22,6 +22,8 @@ namespace Algorithms.Other;
 /// </summary>
 public static class Mandelbrot
 {
+ private const byte Alpha = 255;
+
  /// <summary>
  /// Method to generate the bitmap of the Mandelbrot set. Two types of coordinates
  /// are used: bitmap-coordinates that refer to the pixels and figure-coordinates
@@ -39,7 +41,7 @@ public static class Mandelbrot
  /// <param name="maxStep">Maximum number of steps to check for divergent behavior.</param>
  /// <param name="useDistanceColorCoding">Render in color or black and white.</param>
  /// <returns>The bitmap of the rendered Mandelbrot set.</returns>
- public static Bitmap GetBitmap(
+ public static SKBitmap GetBitmap(
  int bitmapWidth = 800,
  int bitmapHeight = 600,
  double figureCenterX = -0.6,
@@ -69,7 +71,7 @@ public static Bitmap GetBitmap(
  $"{nameof(maxStep)} should be greater than zero");
  }
 
- var bitmap = new Bitmap(bitmapWidth, bitmapHeight);
+ var bitmap = new SKBitmap(bitmapWidth, bitmapHeight);
  var figureHeight = figureWidth / bitmapWidth * bitmapHeight;
 
  // loop through the bitmap-coordinates
@@ -100,22 +102,22 @@ public static Bitmap GetBitmap(
  /// </summary>
  /// <param name="distance">Distance until divergence threshold.</param>
  /// <returns>The color corresponding to the distance.</returns>
- private static Color BlackAndWhiteColorMap(double distance) =>
+ private static SKColor BlackAndWhiteColorMap(double distance) =>
  distance >= 1
- ? Color.FromArgb(255, 0, 0, 0)
- : Color.FromArgb(255, 255, 255, 255);
+ ? new SKColor(0, 0, 0, Alpha)
+ : new SKColor(255, 255, 255, Alpha);
 
  /// <summary>
  /// Color-coding taking the relative distance into account. The Mandelbrot set
  /// is black.
  /// </summary>
  /// <param name="distance">Distance until divergence threshold.</param>
  /// <returns>The color corresponding to the distance.</returns>
- private static Color ColorCodedColorMap(double distance)
+ private static SKColor ColorCodedColorMap(double distance)
  {
  if (distance >= 1)
  {
- return Color.FromArgb(255, 0, 0, 0);
+ return new SKColor(0, 0, 0, Alpha);
  }
 
  // simplified transformation of HSV to RGB
@@ -126,19 +128,19 @@ private static Color ColorCodedColorMap(double distance)
  var hi = (int)Math.Floor(hue / 60) % 6;
  var f = hue / 60 - Math.Floor(hue / 60);
 
- var v = (int)val;
- var p = 0;
- var q = (int)(val * (1 - f * saturation));
- var t = (int)(val * (1 - (1 - f) * saturation));
+ var v = (byte)val;
+ const byte p = 0;
+ var q = (byte)(val * (1 - f * saturation));
+ var t = (byte)(val * (1 - (1 - f) * saturation));
 
  switch (hi)
  {
- case 0: return Color.FromArgb(255, v, t, p);
- case 1: return Color.FromArgb(255, q, v, p);
- case 2: return Color.FromArgb(255, p, v, t);
- case 3: return Color.FromArgb(255, p, q, v);
- case 4: return Color.FromArgb(255, t, p, v);
- default: return Color.FromArgb(255, v, p, q);
+ case 0: return new SKColor(v, t, p, Alpha);
+ case 1: return new SKColor(q, v, p, Alpha);
+ case 2: return new SKColor(p, v, t, Alpha);
+ case 3: return new SKColor(p, q, v, Alpha);
+ case 4: return new SKColor(t, p, v, Alpha);
+ default: return new SKColor(v, p, q, Alpha);
  }
  }