添加项目文件。

Author: Veloctor

ConvertPPM.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0-windows</TargetFramework>
+	<UseWPF>true</UseWPF>
+	<ImplicitUsings>true</ImplicitUsings>
+	<AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+	<PlatformTarget>x64</PlatformTarget>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
+    <DebugType>none</DebugType>
+  </PropertyGroup>
+
+</Project>

ConvertPPM.sln

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+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.3.32811.315
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ConvertPPM", "ConvertPPM.csproj", "{A394BD61-6A4A-43DE-9D4B-4B6526E2FBA8}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{A394BD61-6A4A-43DE-9D4B-4B6526E2FBA8}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{A394BD61-6A4A-43DE-9D4B-4B6526E2FBA8}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{A394BD61-6A4A-43DE-9D4B-4B6526E2FBA8}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{A394BD61-6A4A-43DE-9D4B-4B6526E2FBA8}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {FB628B64-E27F-4D85-85C3-4554935441E0}
+	EndGlobalSection
+EndGlobal

Program.cs

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+using System.IO;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+
+string fileName;
+start:
+if (args.Length == 1) fileName = args[0];
+else
+{
+    Console.WriteLine("请输入要转换的ppm,留空认为\"binary.ppm\":");
+    fileName = Console.ReadLine();
+    if (string.IsNullOrWhiteSpace(fileName)) fileName = "binary.ppm";
+}
+int resX, resY;
+try
+{
+    using StreamReader openText = File.OpenText(fileName);
+    string MagicNumber = openText.ReadLine();
+    if (MagicNumber != "P6")
+    {
+        Console.WriteLine("Magic number is not P6. It's " + MagicNumber);
+        return;
+    }
+    string[] res = openText.ReadLine().Split(' ');
+    resX = Convert.ToInt32(res[0]);
+    resY = Convert.ToInt32(res[1]);
+}
+catch(FileNotFoundException)
+{
+    Console.WriteLine(fileName + "文件未找到.");
+    goto start;
+}
+using var inputFS = File.OpenRead(fileName);
+int enterCount = 3;
+while (enterCount > 0)
+{
+    if (inputFS.ReadByte() == '\n') enterCount--;
+}
+WriteableBitmap bitmap = new(resX, resY, 96, 96, PixelFormats.Rgb24, null);
+bitmap.Lock();
+Span<byte> sp;
+unsafe
+{
+    void* bufferPtr = (void*)bitmap.BackBuffer;
+    sp = new(bufferPtr, resX * resY * 3);
+}
+inputFS.Read(sp);
+bitmap.Unlock();
+PngBitmapEncoder encoder = new();
+encoder.Frames.Add(BitmapFrame.Create(bitmap));
+string outputName = Path.ChangeExtension(fileName, "png");
+using FileStream outputFS = new(outputName, FileMode.Create);
+encoder.Save(outputFS);
+Console.WriteLine(outputName + "输出完毕.");