change using NetVips to reduce memory load

.idea/.idea.lilo-stitcher-console/.idea/.gitignore

@@ -0,0 +1,13 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Rider ignored files
+/modules.xml
+/contentModel.xml
+/projectSettingsUpdater.xml
+/.idea.lilo-stitcher-console.iml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml

.idea/.idea.lilo-stitcher-console/.idea/encodings.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Encoding" addBOMForNewFiles="with BOM under Windows, with no BOM otherwise" />
+</project>

LiloStitcher.cs

@@ -1,10 +1,7 @@
 using Microsoft.Extensions.Caching.Memory;
-using SixLabors.ImageSharp;
+using NetVips;
-using SixLabors.ImageSharp.PixelFormats;
-using SixLabors.ImageSharp.Processing;
-using SixLabors.ImageSharp.Formats.Png;
 
-namespace LiloStitcher;
+namespace lilo_stitcher_console;
 
 public record GenerateRequest(
   string CanvasRect,
@@ -33,9 +30,9 @@ public class TileCache(IMemoryCache cache)
 {
   private const long TileBytes = 720L * 720 * 3;
 
-    public Image<Rgb24>? Get(string key) => cache.TryGetValue(key, out Image<Rgb24>? img) ? img : null;
+  public Image? Get(string key) => cache.TryGetValue(key, out Image? img) ? img : null;
 
-    public void Set(string key, Image<Rgb24> img) =>
+  public void Set(string key, Image img) =>
     cache.Set(key, img, new MemoryCacheEntryOptions
     {
       Size = TileBytes,
@@ -45,14 +42,14 @@ public class TileCache(IMemoryCache cache)
 
 public class TileLoader(TileCache cache, string assetDir)
 {
-    public async Task<Image<Rgb24>> LoadAsync(string name, CancellationToken ct)
+  public async Task<Image> LoadAsync(string name, CancellationToken ct)
   {
     if (cache.Get(name) is { } hit)
       return hit;
     
-        var path = Path.Combine(assetDir, $"{name}.png");
+    var image = await Task.Run(() => 
-        await using var fs = File.OpenRead(path);
+      Image.NewFromFile(Path.Combine(assetDir, $"{name}.png"), access: Enums.Access.Sequential), ct);
-        var image = await Image.LoadAsync<Rgb24>(fs, ct).ConfigureAwait(false);
+
     cache.Set(name, image);
     return image;
   }
@@ -60,57 +57,36 @@ public class TileLoader(TileCache cache, string assetDir)
 
 public class LiloStitcher(TileLoader loader)
 {
-    private const int TileSize = 720;
+    public async Task<string> CreateImageAsync(GenerateRequest req, CancellationToken ct)
-
-    private static readonly GraphicsOptions _copy = new()
     {
-        Antialias = false,
+        (int rowMin, int colMin, int rows, int cols) = ParseCanvas(req.CanvasRect);
-        AlphaCompositionMode = PixelAlphaCompositionMode.Src,
-        BlendPercentage = 1f
-    };
 
-    public async Task<byte[]> CreateImageAsync(GenerateRequest req, CancellationToken ct)
+        Validate(req.CropOffset, nameof(req.CropOffset));
-    {
+        Validate(req.CropSize,   nameof(req.CropSize));
-        var parts = req.CanvasRect.ToUpperInvariant().Split(':', StringSplitOptions.TrimEntries |
-                                                            StringSplitOptions.RemoveEmptyEntries);
-        var part1 = PlateCoordinate.Parse(parts[0]);
-        var part2 = PlateCoordinate.Parse(parts[1]);
 
-        int rowMin = Math.Min(part1.Row, part2.Row);
+        double scale = req.OutputScale;
-        int rowMax = Math.Max(part1.Row, part2.Row);
+        if (scale <= 0 || scale > 1)
-        int colMin = Math.Min(part1.Col, part2.Col);
+            throw new ArgumentOutOfRangeException(nameof(req.OutputScale));
-        int colMax = Math.Max(part1.Col, part2.Col);
 
-        int rows = rowMax - rowMin + 1;
+        var tiles = new List<Image>(rows * cols);
-        int cols = colMax - colMin + 1;
-
-        var names = Enumerable.Range(rowMin, rows)
-            .SelectMany(r => Enumerable.Range(colMin, cols).Select(c => $"{RowName(r)}{c}"))
-            .ToArray();
-
-        var bitmaps = await Task.WhenAll(names.Select(n => loader.LoadAsync(n, ct))).ConfigureAwait(false);
-        var stitched = new Image<Rgb24>(cols * TileSize, rows * TileSize);
-
-        stitched.Mutate(context =>
-        {
-            int idx = 0;
         for( int row = 0; row < rows; row++ )
         {
-                for (int col = 0; col < cols; col++, idx++)
+          for( int col = 0; col < cols; col++ )
           {
-                    context.DrawImage(bitmaps[idx], new Point(col * TileSize, row * TileSize), 1f);
+            string id = $"{RowName( rowMin + row )}{colMin + col}";
+            var tile = await loader.LoadAsync( id, ct );
+            if( scale < 1 ) tile = tile.Resize( scale );
+            tiles.Add( tile );
           }
         }
-        });
 
-        Validate(req.CropOffset, 2, nameof(req.CropOffset), inclusiveUpper: true);
+        var mosaic = Image.Arrayjoin(tiles.ToArray(), across: cols);
-        Validate(req.CropSize, 2, nameof(req.CropSize), inclusiveUpper: true);
 
-        int offsetX = (int)Math.Truncate(req.CropOffset[0] * stitched.Width);
+        int offsetX = (int)Math.Truncate(req.CropOffset[0] * mosaic.Width);
-        int offsetY = (int)Math.Truncate(req.CropOffset[1] * stitched.Height);
+        int offsetY = (int)Math.Truncate(req.CropOffset[1] * mosaic.Height);
 
-        int restWidth  = stitched.Width  - offsetX;
+        int restWidth = mosaic.Width - offsetX;
-        int restHeight = stitched.Height - offsetY;
+        int restHeight = mosaic.Height - offsetY;
 
         int cropWidth = Math.Max(1, (int)Math.Truncate(req.CropSize[0] * restWidth));
         int cropHeight = Math.Max(1, (int)Math.Truncate(req.CropSize[1] * restHeight));
@@ -118,44 +94,32 @@ public class LiloStitcher(TileLoader loader)
         int cropX = (int)Math.Truncate(offsetX / 2.0 + (restWidth - cropWidth) / 2.0);
         int cropY = (int)Math.Truncate(offsetY / 2.0 + (restHeight - cropHeight) / 2.0);
 
-        var cropRect = new Rectangle(cropX, cropY, cropWidth, cropHeight);
+        var cropRect = mosaic.Crop(cropX, cropY, cropWidth, cropHeight);
-        using var cropped = stitched.Clone(context => context.Crop(cropRect));
 
-        double scale = Math.Clamp(req.OutputScale, 0.0, 1.0);
+        string tmpPath = Path.Combine(Path.GetTempPath(), $"mosaic-{Guid.NewGuid():N}.png");
-        if (scale <= 0 || scale > 1)
+        cropRect.WriteToFile(tmpPath); 
-            throw new ArgumentOutOfRangeException(nameof(req.OutputScale), "OutputScale must be > 0 and ≤ 1.0");
 
-        Image<Rgb24> output;
+        return tmpPath;
-        if (scale < 1.0)
-        {
-            int width = Math.Max(1, (int)Math.Truncate(cropWidth * scale));
-            int height = Math.Max(1, (int)Math.Truncate(cropHeight * scale));
-            output = cropped.Clone(ctx => ctx.Resize(width, height));
-        }
-        else
-        {
-            output = cropped.Clone();
     }
 
-        using var memStream = new MemoryStream();
+    private static (int rowMin, int colMin, int rows, int cols) ParseCanvas(string rect)
-        await output.SaveAsync(memStream, new PngEncoder
     {
-            CompressionLevel = PngCompressionLevel.Level1
+        var parts = rect.ToUpperInvariant().Split(':', StringSplitOptions.RemoveEmptyEntries);
-        }, ct).ConfigureAwait(false);
+        var part1 = PlateCoordinate.Parse(parts[0]);
-        return memStream.ToArray();
+        var part2 = PlateCoordinate.Parse(parts[1]);
+        int rowMin = Math.Min(part1.Row, part2.Row); 
+        int rowMax = Math.Max(part1.Row, part2.Row);
+        int colMin = Math.Min(part1.Col, part2.Col); 
+        int colMax = Math.Max(part1.Col, part2.Col);
+        return (rowMin, colMin, rowMax - rowMin + 1, colMax - colMin + 1);
     }
 
-    static void Validate(double[] arr, int len, string name, bool inclusiveUpper)
+    private static void Validate(double[] arr, string name)
     {
-        if (arr is null || arr.Length < len)
+        if (arr is null || arr.Length < 2) 
-            throw new ArgumentException($"{name} must have length {len}");
+          throw new ArgumentException($"{name} length");
-        double upper = inclusiveUpper ? 1.0 : 1.0 - double.Epsilon;
+        if (arr.Any(x => x < 0 || x > 1)) 
-        for (int i = 0; i < len; i++)
+          throw new ArgumentOutOfRangeException(name);
-        {
-            var v = arr[i];
-            if (v < 0 || v > upper)
-                throw new ArgumentOutOfRangeException($"{name}[{i}]= {v} outside [0,{upper}]");
-        }
     }
 
     static string RowName(int row)

Program.cs

@@ -1,20 +1,25 @@
-using System.Diagnostics;
+using lilo_stitcher_console;
+using System.Diagnostics;
 using Microsoft.Extensions.Caching.Memory;
 
 namespace LiloStitcher;
+
 public static class Program
 {
   public static async Task<int> Main( string[] args )
   {
     try
     {
+      NetVips.NetVips.Init();
+      NetVips.NetVips.Concurrency = 3;
+      
       Stopwatch sw = Stopwatch.StartNew();
       var begin = sw.ElapsedMilliseconds;
       var opt = new Options
       {
         CanvasRect = "A1:AE55",
-                CropOffset = [0.4, 0.4],
+        CropOffset = new[] { 0.4, 0.4 },
-                CropSize = [0.8, 0.8],
+        CropSize = new[] { 0.8, 0.8 },
         OutputScale = 0.5,
         OutputPath = "stitched.png"
       };
@@ -22,10 +27,10 @@ public static class Program
       string tileFilePath = "../tiles1705"; // should later be directed to the read-only `ASSET_PATH_RO` environment variable
       string assetDir = Path.GetFullPath(Path.Combine(Directory.GetCurrentDirectory(), tileFilePath));
 
-            using var memCache = new MemoryCache(new MemoryCacheOptions { SizeLimit = 256L * 1024 * 1024 });
+      using var memCache = new MemoryCache(new MemoryCacheOptions { SizeLimit = 128L * 1024 * 1024 });
       var tileCache = new TileCache(memCache);
       var loader = new TileLoader(tileCache, assetDir);
-            var stitcher = new LiloStitcher(loader);
+      var stitcher = new lilo_stitcher_console.LiloStitcher(loader);
 
       var req = new GenerateRequest(
         opt.CanvasRect!,
@@ -35,12 +40,14 @@ public static class Program
       );
 
       Console.WriteLine("Stitching...");
-            var pngBytes = await stitcher.CreateImageAsync(req, CancellationToken.None);
+      var png = await stitcher.CreateImageAsync(req, CancellationToken.None);
+      File.Move( png, opt.OutputPath!, overwrite: true );
       
-            File.WriteAllBytes(opt.OutputPath!, pngBytes);
+      long bytes = new FileInfo( opt.OutputPath! ).Length;
-            Console.WriteLine($"Done. Wrote {opt.OutputPath}  ({pngBytes.Length / 1024.0:F1} KB)");
+      Console.WriteLine($"Done. Wrote {opt.OutputPath}  ({bytes / 1024.0:F1} KB)");
 
       Console.WriteLine(sw.ElapsedMilliseconds - begin);
+      
       return 0;
     }
     catch( Exception ex )

lilo-stitcher-console.csproj

@@ -2,15 +2,17 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
     <RootNamespace>lilo_stitcher_console</RootNamespace>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
+    <LangVersion>preview</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="9.0.7" />
-    <PackageReference Include="SixLabors.ImageSharp" Version="3.1.10" />
+    <PackageReference Include="NetVips" Version="3.1.0" />
+    <PackageReference Include="NetVips.Native.linux-x64" Version="8.17.1" />
   </ItemGroup>
 
 </Project>