Implement ImageCreatorImageSharp using SixLabors.ImageSharp for image processing

- Added ImageCreatorImageSharp class for image creation, handling EXIF orientation, resizing, and saving images.
- Replaced GDI+ dependencies with ImageSharp for cross-platform compatibility.
- Introduced methods for drawing text and logos on images, including handling transparency and positioning.
- Created a test plan for validating ImageCreatorImageSharp functionality, focusing on image resizing, text positioning, logo features, and EXIF orientation.
- Added documentation for the test plan outlining goals, project structure, and implementation notes.

MaddoShared.ImageSharpTests/Helpers/CreatorFactory.cs

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+using System.IO;
+using Microsoft.Extensions.Logging.Abstractions;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace MaddoShared.ImageSharpTests.Helpers
+{
+    public static class CreatorFactory
+    {
+        public static MaddoShared.PicSettings CreateDefaultPicSettings()
+        {
+            return new MaddoShared.PicSettings
+            {
+                DimStandard = 48,
+                DimStandardMiniatura = 12,
+                LarghezzaSmall = 150,
+                AltezzaSmall = 150,
+                LarghezzaBig = 800,
+                AltezzaBig = 600,
+                Trasparenza = 0,
+                IlFont = "Arial",
+                Grassetto = false,
+                Posizione = "CENTRO",
+                Allineamento = "CENTRO",
+                Margine = 10,
+                MargVert = 10,
+                TestoMin = false,
+                AggNumTempMin = false,
+                CreaMiniature = false,
+                LogoAggiungi = false,
+                LogoAltezza = 100,
+                LogoLarghezza = 100,
+                LogoMargine = "0",
+                JpegQuality = 90,
+                JpegQualityMin = 75,
+            };
+        }
+
+        public static MaddoShared.ImageCreatorImageSharp CreateImageCreator(MaddoShared.PicSettings settings)
+        {
+            var logger = NullLogger<MaddoShared.ImageCreatorImageSharp>.Instance;
+            return new MaddoShared.ImageCreatorImageSharp(settings, logger);
+        }
+    }
+}

MaddoShared.ImageSharpTests/Helpers/PixelInspector.cs

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+using System;
+using SixLabors.ImageSharp;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace MaddoShared.ImageSharpTests.Helpers
+{
+    public static class PixelInspector
+    {
+        public static int CountNonBackgroundPixels(string path, int x, int y, int width, int height, Rgba32 background, int tolerance = 0)
+        {
+            using var img = SixLabors.ImageSharp.Image.Load<Rgba32>(path);
+            var bx = Math.Max(0, x);
+            var by = Math.Max(0, y);
+            var bw = Math.Min(width, img.Width - bx);
+            var bh = Math.Min(height, img.Height - by);
+            if (bw <= 0 || bh <= 0) return 0;
+
+            int count = 0;
+            img.ProcessPixelRows(accessor =>
+            {
+                for (int yy = by; yy < by + bh; yy++)
+                {
+                    var row = accessor.GetRowSpan(yy);
+                    for (int xx = bx; xx < bx + bw; xx++)
+                    {
+                        var p = row[xx];
+                        if (!IsApproximatelyEqual(p, background, tolerance)) count++;
+                    }
+                }
+            });
+
+            return count;
+        }
+
+        private static bool IsApproximatelyEqual(Rgba32 a, Rgba32 b, int tol)
+        {
+            return Math.Abs(a.R - b.R) <= tol && Math.Abs(a.G - b.G) <= tol && Math.Abs(a.B - b.B) <= tol && Math.Abs(a.A - b.A) <= tol;
+        }
+    }
+}

MaddoShared.ImageSharpTests/Helpers/TempWorkspace.cs

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+using System;
+using System.IO;
+
+namespace MaddoShared.ImageSharpTests.Helpers
+{
+    public sealed class TempWorkspace : IDisposable
+    {
+        public DirectoryInfo Root { get; }
+        public DirectoryInfo SourceDir { get; }
+        public DirectoryInfo DestDir { get; }
+
+        public TempWorkspace()
+        {
+            var root = Path.Combine(Path.GetTempPath(), "MaddoShared.ImageSharpTests", Guid.NewGuid().ToString("N"));
+            Root = Directory.CreateDirectory(root);
+            SourceDir = Directory.CreateDirectory(Path.Combine(Root.FullName, "Source"));
+            DestDir = Directory.CreateDirectory(Path.Combine(Root.FullName, "Dest"));
+        }
+
+        public void Dispose()
+        {
+            try
+            {
+                if (Root.Exists)
+                    Root.Delete(true);
+            }
+            catch
+            {
+                // best-effort cleanup
+            }
+        }
+    }
+}

MaddoShared.ImageSharpTests/Helpers/TestImageFactory.cs

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+using System.IO;
+using SixLabors.ImageSharp;
+using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Processing;
+using SixLabors.ImageSharp.Formats.Jpeg;
+using SixLabors.ImageSharp.Metadata.Profiles.Exif;
+
+namespace MaddoShared.ImageSharpTests.Helpers
+{
+    public static class TestImageFactory
+    {
+        public static string CreateSolidJpeg(string directory, string fileName, int width, int height, Rgba32 color)
+        {
+            Directory.CreateDirectory(directory);
+            var path = Path.Combine(directory, fileName);
+            using var img = new Image<Rgba32>(width, height, color);
+            var encoder = new JpegEncoder { Quality = 90 };
+            img.Save(path, encoder);
+            return path;
+        }
+
+        public static string CreateSolidPng(string directory, string fileName, int width, int height, Rgba32 color)
+        {
+            Directory.CreateDirectory(directory);
+            var path = Path.Combine(directory, fileName);
+            using var img = new Image<Rgba32>(width, height, color);
+            img.SaveAsPng(path);
+            return path;
+        }
+
+        public static string CreateJpegWithExifOrientation(string directory, string fileName, int width, int height, Rgba32 color, ushort orientation)
+        {
+            Directory.CreateDirectory(directory);
+            var path = Path.Combine(directory, fileName);
+            using var img = new Image<Rgba32>(width, height, color);
+            // Add EXIF orientation
+            var profile = new ExifProfile();
+            profile.SetValue(ExifTag.Orientation, orientation);
+            img.Metadata.ExifProfile = profile;
+            var encoder = new JpegEncoder { Quality = 90 };
+            img.Save(path, encoder);
+            return path;
+        }
+    }
+}

MaddoShared.ImageSharpTests/MaddoShared.ImageSharpTests.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <LangVersion>latest</LangVersion>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
+    <PackageReference Include="MSTest.TestAdapter" Version="4.1.0" />
+    <PackageReference Include="MSTest.TestFramework" Version="4.1.0" />
+    <PackageReference Include="FluentAssertions" Version="8.8.0" />
+    <PackageReference Include="Moq" Version="4.20.72" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="10.0.3" />
+    <PackageReference Include="SixLabors.ImageSharp" Version="3.1.12" />
+    <PackageReference Include="SixLabors.ImageSharp.Drawing" Version="2.1.7" />
+    <PackageReference Include="SixLabors.Fonts" Version="2.1.3" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\MaddoShared\MaddoShared.csproj" />
+  </ItemGroup>
+
+</Project>

MaddoShared.ImageSharpTests/Tests/ImageResizingTests.cs

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+using System.IO;
+using System.Threading.Tasks;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using SixLabors.ImageSharp.PixelFormats;
+using MaddoShared.ImageSharpTests.Helpers;
+
+namespace MaddoShared.ImageSharpTests.Tests
+{
+    [TestClass]
+    public class ImageResizingTests
+    {
+        [TestMethod]
+        public async Task BigImageResizesRespectSettings()
+        {
+            using var ws = new TempWorkspace();
+
+            // create a large input image
+            var inputPath = TestImageFactory.CreateSolidJpeg(ws.SourceDir.FullName, "input.jpg", 1600, 1200, new Rgba32(200, 200, 200, 255));
+
+            var pic = CreatorFactory.CreateDefaultPicSettings();
+            pic.LarghezzaBig = 800;
+            pic.AltezzaBig = 600;
+            pic.CreaMiniature = false;
+
+            var svc = CreatorFactory.CreateImageCreator(pic);
+
+            var state = new MaddoShared.ImageState
+            {
+                WorkFile = new FileInfo(inputPath),
+                DestDir = ws.DestDir,
+                SourceDir = ws.SourceDir
+            };
+
+            await svc.CreateImageAsync(state, null);
+
+            var outPath = Path.Combine(ws.DestDir.FullName, state.NomeFileBig);
+            using var outImg = SixLabors.ImageSharp.Image.Load<Rgba32>(outPath);
+
+            Assert.AreEqual(800, outImg.Width);
+            Assert.AreEqual(600, outImg.Height);
+        }
+    }
+}

MaddoShared.ImageSharpTests/Tests/TextPositioningTests.cs

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+using System.IO;
+using System.Threading.Tasks;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using SixLabors.ImageSharp.PixelFormats;
+using MaddoShared.ImageSharpTests.Helpers;
+
+namespace MaddoShared.ImageSharpTests.Tests
+{
+    [TestClass]
+    public class TextPositioningTests
+    {
+        [TestMethod]
+        public async Task TextAtBottom_IncreasesNonBackgroundPixelCountInBottomBand()
+        {
+            using var ws = new TempWorkspace();
+
+            // create white background input
+            var inputPath = TestImageFactory.CreateSolidJpeg(ws.SourceDir.FullName, "input.jpg", 800, 600, new Rgba32(255, 255, 255, 255));
+
+            var pic = CreatorFactory.CreateDefaultPicSettings();
+            pic.Posizione = "BASSO";
+            pic.DimStandard = 48; // big text
+            pic.TestoFirmaStart = "SAMPLE TEXT";
+            pic.CreaMiniature = false;
+
+            var svc = CreatorFactory.CreateImageCreator(pic);
+
+            var state = new MaddoShared.ImageState
+            {
+                WorkFile = new FileInfo(inputPath),
+                DestDir = ws.DestDir,
+                SourceDir = ws.SourceDir
+            };
+
+            await svc.CreateImageAsync(state, null);
+
+            var outPath = Path.Combine(ws.DestDir.FullName, state.NomeFileBig);
+
+            // bottom band (lower 25% of image)
+            var bottomY = (int)(600 * 0.75);
+            var bottomCount = PixelInspector.CountNonBackgroundPixels(outPath, 0, bottomY, 800, 600 - bottomY, new Rgba32(255, 255, 255, 255), tolerance: 10);
+
+            // top band (upper 25%)
+            var topCount = PixelInspector.CountNonBackgroundPixels(outPath, 0, 0, 800, (int)(600 * 0.25), new Rgba32(255, 255, 255, 255), tolerance: 10);
+
+            Assert.IsTrue(bottomCount > 50, $"Expected text pixels in bottom band, found {bottomCount}");
+            Assert.IsTrue(bottomCount > topCount, "Expected more non-background pixels at bottom than top");
+        }
+    }
+}