Create a small demo application for StbImage.

CMakeLists.txt

@@ -5,9 +5,10 @@ project(rf_stbi LANGUAGES C VERSION 1.0)
 if (NOT ("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin"))
     add_compile_options(-static-libgcc -static-libstdc++ -fno-exceptions)
 endif()
+add_compile_options(-O3)
 
 add_library(stbi SHARED "rf_stbi.c")
-install(
+    install(
     TARGETS stbi
     RUNTIME DESTINATION .
     LIBRARY DESTINATION .)

NativeTypeNameAttribute.cs

@@ -1,12 +0,0 @@
-using System;
-
-namespace Quik.Stb
-{
-    [AttributeUsage(System.AttributeTargets.All, Inherited = false, AllowMultiple = true)]
-    internal sealed class NativeTypeNameAttribute : System.Attribute
-    {
-        public NativeTypeNameAttribute(string typename)
-        {
-        }
-    }
-}

ReFuel.StbImage.Viewer/Program.cs

@@ -0,0 +1,209 @@
+/*
+ * ReFuel.StbImage.Viewer - A simple image viewer demo for ReFuel.StbImage.
+ * ------------------------------------------------------------------------
+ *
+ * Pass an image file as path (or drag and drop over the executable or window) to view
+ * of the file formats stb_image supports. Otherwise the default embedded image will be
+ * shown.
+ *
+ * The demo uses OpenGL2.1 for brevity sake - I did not feel like writing a shader program
+ * for this demo. It is very easy to port this demo to modern OpenGL if desired. Just
+ * replace the FFP calls with the equivalent programmable pipeline calls (glVertexAttribPointer,
+ * glUseShader and its friends).
+ */
+
+using System.Reflection;
+using System.Runtime.InteropServices;
+using OpenTK.Graphics.OpenGL;
+using OpenTK.Mathematics;
+using OpenTK.Windowing.Common;
+using OpenTK.Windowing.Desktop;
+using ReFuel.Stb;
+
+NativeWindow window = new NativeWindow(new NativeWindowSettings()
+{
+    Profile = ContextProfile.Any,
+    APIVersion = new Version(2, 1),
+    Title = "ReFuel StbImage Viewer",
+    AutoLoadBindings = true,
+    Flags = ContextFlags.Default,
+});
+
+bool quit = false;
+int texture = 0;
+int imageWidth = 0, imageHeight = 0;
+
+// This flag is important for OpenGL users, as texture coordinate systems
+// are the opposite of what most image formats use. Y is up not down.
+// Does not matter for DX, for example.
+StbImage.FlipVerticallyOnLoad = true;
+
+Vertex[] vertices = new Vertex[]
+{
+    new Vertex(-1, -1, 0, 0),
+    new Vertex(1, -1, 1, 0),
+    new Vertex(1, 1, 1, 1),
+    new Vertex(-1, -1, 0, 0),
+    new Vertex(1, 1, 1, 1),
+    new Vertex(-1, 1, 0, 1),
+};
+
+LoadImage(args.Length > 0 ? args[0] : null);
+
+GL.ClearColor(Color4.Black);
+GL.Enable(EnableCap.Texture2D);
+GL.Enable(EnableCap.Blend);
+GL.BlendFunc(BlendingFactor.SrcAlpha, BlendingFactor.OneMinusSrcAlpha); // conventional blending function.
+GL.EnableClientState(ArrayCap.VertexArray);
+GL.EnableClientState(ArrayCap.TextureCoordArray);
+GL.EnableClientState(ArrayCap.ColorArray);
+
+window.Closing += (_) => quit = true;
+window.FramebufferResize += (_) => {
+    ResizeImage();
+    Paint();
+};
+window.FileDrop += (args) => 
+    LoadImage(
+        args.FileNames
+            .Select(x => new FileInfo(x))
+            .FirstOrDefault(x => x.Exists)?.FullName);
+
+window.WindowState = WindowState.Normal;
+while (!quit)
+{
+    NativeWindow.ProcessWindowEvents(true);
+    Paint();
+};
+
+void Paint()
+{
+    GL.Clear(ClearBufferMask.ColorBufferBit);
+    GL.Viewport(0, 0, window.FramebufferSize.X, window.FramebufferSize.Y);
+    GL.BindTexture(TextureTarget.Texture2D, texture);
+
+    unsafe
+    {
+        fixed (Vertex* pvert = vertices)
+        {
+            // We have to do it this way because the garbage collector may
+            // move the vertex data at any time. The OpenGL client will
+            // handle streaming the data at the glDrawArrays call, unlike
+            // the modern method.
+            GL.VertexPointer(2, VertexPointerType.Float, 32, (nint)(&pvert->X));
+            GL.TexCoordPointer(2, TexCoordPointerType.Float, 32, (nint)(&pvert->U));
+            GL.ColorPointer(4, ColorPointerType.Float, 32, (nint)(&pvert->Color));
+            GL.DrawArrays(PrimitiveType.Triangles, 0, vertices.Length);
+        }
+    }
+
+    window.Context.SwapBuffers();
+}
+
+void ResizeImage()
+{
+    // Regenerates the vertex positions to maintain the aspect ratio and fill the window.
+    float windowAspect = (float)window.FramebufferSize.X / window.FramebufferSize.Y;
+    float imageAspect = (float)imageWidth / imageHeight;
+    float ratio = imageAspect / windowAspect;
+
+    float widthNDC, heightNDC;
+    if (ratio > 1)
+    {
+        widthNDC = 2.0f;
+        heightNDC = 2.0f / ratio;
+    }
+    else
+    {
+        heightNDC = 2.0f;
+        widthNDC = 2.0f * ratio;
+    }
+
+    vertices[0].X = -widthNDC / 2; vertices[0].Y = -heightNDC / 2;
+    vertices[1].X = widthNDC / 2; vertices[1].Y = -heightNDC / 2;
+    vertices[2].X = widthNDC / 2; vertices[2].Y = heightNDC / 2;
+    vertices[3].X = -widthNDC / 2; vertices[3].Y = -heightNDC / 2;
+    vertices[4].X = widthNDC / 2; vertices[4].Y = heightNDC / 2;
+    vertices[5].X = -widthNDC / 2; vertices[5].Y = heightNDC / 2;
+}
+
+void LoadImage(string? path)
+{
+    // Load the given image, or the default if the path is null, or any other error happens.
+    StbImage? image = null;
+    if (path != null && File.Exists(path))
+    {
+        try
+        {
+            using Stream str = File.OpenRead(path);
+            StbImage.TryLoad(out image, str);
+        }
+        catch
+        {
+            // Ignore
+        }
+    }
+
+    if (image == null)
+    {
+        using Stream str = Assembly.GetExecutingAssembly().GetManifestResourceStream("default.png")!;
+        image = StbImage.Load(str);
+    }
+
+    // Boilerplate code for creating a new OpenGL texture.
+
+    GL.DeleteTexture(texture);
+    texture = GL.GenTexture();
+    GL.BindTexture(TextureTarget.Texture2D, texture);
+    GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba, image.Width, image.Height, 0, image.Format switch
+    {
+        StbiImageFormat.Grey => PixelFormat.Red,
+        StbiImageFormat.GreyAlpha => PixelFormat.Rg,
+        StbiImageFormat.Rgb => PixelFormat.Rgb,
+        StbiImageFormat.Rgba => PixelFormat.Rgba,
+        _ => throw new Exception()
+    }, image.IsFloat ? PixelType.Float : PixelType.UnsignedByte, image.ImagePointer);
+    
+    // Generate mipmaps for better minification.
+    GL.GenerateMipmap(GenerateMipmapTarget.Texture2D);
+    // Enable them.
+    GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.LinearMipmapLinear);
+    GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);
+
+    // Set texture wrap mode to clamp to border to prevent bleeding on the image edges.
+    GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapS, (int)TextureWrapMode.ClampToBorder);
+    GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapT, (int)TextureWrapMode.ClampToBorder);
+
+    // For R or RA format images, we need to set the swizzle mask.
+    switch (image.Format)
+    {
+        case StbiImageFormat.Grey:
+            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureSwizzleR, (int)TextureSwizzle.Red);
+            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureSwizzleG, (int)TextureSwizzle.Red);
+            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureSwizzleB, (int)TextureSwizzle.Red);
+            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureSwizzleA, (int)TextureSwizzle.One);
+            break;
+        case StbiImageFormat.GreyAlpha:
+            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureSwizzleR, (int)TextureSwizzle.Red);
+            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureSwizzleG, (int)TextureSwizzle.Red);
+            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureSwizzleA, (int)TextureSwizzle.Green);
+            // Yes the last channel is green, we uploaded the texture with the Rg color format.
+            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureSwizzleB, (int)TextureSwizzle.Red);
+            break;
+    }
+
+    imageWidth = image.Width;
+    imageHeight = image.Height;
+    ResizeImage();
+
+    image.Dispose();
+}
+
+// Vertex struct for convenience. Padded to 32 bytes for memory alignment.
+[StructLayout(LayoutKind.Sequential, Size = 32)]
+struct Vertex(float x, float y, float u, float v)
+{
+    public float X = x, Y = y, U = u, V = v;
+    public Color4 Color = Color4.White;
+}
+

ReFuel.StbImage.Viewer/ReFuel.StbImage.Viewer.csproj

@@ -0,0 +1,18 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <!-- <ProjectReference Include="..\ReFuel.StbImage\ReFuel.StbImage.csproj" /> -->
+    <PackageReference Include="ReFuel.StbImage" Version="2.1.0"/>
+    <PackageReference Include="OpenTK" Version="4.9.4" /> 
+    <EmbeddedResource Include="../rf_stbimage.png" LogicalName="default.png"/>
+  </ItemGroup>
+
+</Project>

ReFuel.StbImage.sln

@@ -3,20 +3,46 @@ Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio Version 17
 VisualStudioVersion = 17.0.31903.59
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ReFuel.StbImage", "ReFuel.StbImage.csproj", "{413ACBF4-3851-416F-B2A2-F7157EC306B2}"
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ReFuel.StbImage", "ReFuel.StbImage\ReFuel.StbImage.csproj", "{EB001CC8-6821-4579-BD5D-27C56A3C121E}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ReFuel.StbImage.Viewer", "ReFuel.StbImage.Viewer\ReFuel.StbImage.Viewer.csproj", "{4CFB8D5B-8CE9-46EE-A34B-0D61693BDE50}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
+		Debug|x64 = Debug|x64
+		Debug|x86 = Debug|x86
 		Release|Any CPU = Release|Any CPU
+		Release|x64 = Release|x64
+		Release|x86 = Release|x86
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{EB001CC8-6821-4579-BD5D-27C56A3C121E}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{EB001CC8-6821-4579-BD5D-27C56A3C121E}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{EB001CC8-6821-4579-BD5D-27C56A3C121E}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{EB001CC8-6821-4579-BD5D-27C56A3C121E}.Debug|x64.Build.0 = Debug|Any CPU
+		{EB001CC8-6821-4579-BD5D-27C56A3C121E}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{EB001CC8-6821-4579-BD5D-27C56A3C121E}.Debug|x86.Build.0 = Debug|Any CPU
+		{EB001CC8-6821-4579-BD5D-27C56A3C121E}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{EB001CC8-6821-4579-BD5D-27C56A3C121E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{EB001CC8-6821-4579-BD5D-27C56A3C121E}.Release|x64.ActiveCfg = Release|Any CPU
+		{EB001CC8-6821-4579-BD5D-27C56A3C121E}.Release|x64.Build.0 = Release|Any CPU
+		{EB001CC8-6821-4579-BD5D-27C56A3C121E}.Release|x86.ActiveCfg = Release|Any CPU
+		{EB001CC8-6821-4579-BD5D-27C56A3C121E}.Release|x86.Build.0 = Release|Any CPU
+		{4CFB8D5B-8CE9-46EE-A34B-0D61693BDE50}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{4CFB8D5B-8CE9-46EE-A34B-0D61693BDE50}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{4CFB8D5B-8CE9-46EE-A34B-0D61693BDE50}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{4CFB8D5B-8CE9-46EE-A34B-0D61693BDE50}.Debug|x64.Build.0 = Debug|Any CPU
+		{4CFB8D5B-8CE9-46EE-A34B-0D61693BDE50}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{4CFB8D5B-8CE9-46EE-A34B-0D61693BDE50}.Debug|x86.Build.0 = Debug|Any CPU
+		{4CFB8D5B-8CE9-46EE-A34B-0D61693BDE50}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{4CFB8D5B-8CE9-46EE-A34B-0D61693BDE50}.Release|Any CPU.Build.0 = Release|Any CPU
+		{4CFB8D5B-8CE9-46EE-A34B-0D61693BDE50}.Release|x64.ActiveCfg = Release|Any CPU
+		{4CFB8D5B-8CE9-46EE-A34B-0D61693BDE50}.Release|x64.Build.0 = Release|Any CPU
+		{4CFB8D5B-8CE9-46EE-A34B-0D61693BDE50}.Release|x86.ActiveCfg = Release|Any CPU
+		{4CFB8D5B-8CE9-46EE-A34B-0D61693BDE50}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
 	EndGlobalSection
-	GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		{413ACBF4-3851-416F-B2A2-F7157EC306B2}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{413ACBF4-3851-416F-B2A2-F7157EC306B2}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{413ACBF4-3851-416F-B2A2-F7157EC306B2}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{413ACBF4-3851-416F-B2A2-F7157EC306B2}.Release|Any CPU.Build.0 = Release|Any CPU
-	EndGlobalSection
 EndGlobal

ReFuel.StbImage/ReFuel.StbImage.csproj

@@ -1,19 +1,20 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
-    <Nullable>disable</Nullable>
-    <LangVersion>7.3</LangVersion>
+    <TargetFrameworks>net6.0;net8.0</TargetFrameworks>
+    <Nullable>enable</Nullable>
+    <LangVersion>latest</LangVersion>
     <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
     <RuntimeIdentifiers>linux-arm;linux-arm64;linux-x64;win-x86;win-x64;osx-arm64;osx-x64</RuntimeIdentifiers>
     <RootNamespace>ReFuel.Stb</RootNamespace>
+    <Optimize>true</Optimize>
   </PropertyGroup>
 
   <PropertyGroup>
     <!-- Nuget Properties. -->
     <GeneratePackageOnBuild>True</GeneratePackageOnBuild>
     <PackageId>ReFuel.StbImage</PackageId>
-    <Version>1.0.1</Version>
+    <Version>2.1.0</Version>
     <Authors>STBI Authors, H. Utku Maden</Authors>
     <Description>
       A C# wrapper for the ubiquitous stb_image.h and stb_image_write.h library.
@@ -21,6 +22,21 @@
     <PackageReadmeFile>README.md</PackageReadmeFile>
     <PackageLicenseFile>LICENSE.md</PackageLicenseFile>
     <PackageIcon>images\icon.png</PackageIcon>
+    <PackageProjectUrl>https://refuel.mixedup.dev/docs/ReFuel.StbImage.html</PackageProjectUrl>
+    <RepositoryUrl>https://git.mixedup.dev/ReFuel/ReFuel.StbImage</RepositoryUrl>
+    <RepositoryType>git</RepositoryType>
+    <PackageTags>stb; stb_image; stbi; image; load; save; read; write</PackageTags>
+    <PackageReleaseNotes># 2.1.0 (ABI BRAKING)
+* Fixed calling convention of unmanaged function pointers. (Thanks NogginBops!)
+* Modified StbiStreamWrapper in order to fixed backing delegates of function pointers from being prematurely collected 
+  by release mode JIT and the GC. StbiStreamWrapper.Callbacks is now a readonly field. (ABI BREAKING)
+
+# 2.0.1
+* Enabled optimizations across the board for native and managed assemblies.
+
+# 2.0.0
+* Exposed stbi_image_write.h
+* Moved native function calls to ReFuel.Stb.Native</PackageReleaseNotes>
   </PropertyGroup>
 
   <!--
@@ -30,8 +46,8 @@
     that determines a lot of load paths for projects.
   -->
   <ItemGroup>
-    <Content Include="*.md" Pack="true" PackagePath="/"/>
-    <None Include="rf_stbimage.png" Pack="true" PackagePath="images\icon.png"/>
+    <Content Include="*.md" Pack="true" PackagePath="/" />
+    <None Include="rf_stbimage.png" Pack="true" PackagePath="images\icon.png" />
     <Content Include="runtimes/linux-arm/native/*.so">
       <PackagePath>runtimes/linux-arm/native/</PackagePath>
       <Pack>true</Pack>
@@ -40,7 +56,7 @@
     <Content Include="runtimes/linux-arm64/native/*.so">
       <PackagePath>runtimes/linux-arm64/native/</PackagePath>
       <Pack>true</Pack>
-      <CopyToOutputDirectory>PreserveNewest/</CopyToOutputDirectory>
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
     <Content Include="runtimes/linux-x64/native/*.so">
       <PackagePath>runtimes/linux-x64/native/</PackagePath>

ReFuel.StbImage/StbImage.cs

@@ -0,0 +1,575 @@
+using ReFuel.Stb.Native;
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.IO;
+using System.Runtime.InteropServices;
+
+namespace ReFuel.Stb
+{
+    /// <summary>
+    /// A class that encompasses all features of stb_image.h in a safe way.
+    /// </summary>
+    public unsafe class StbImage : IDisposable
+    {
+        private bool isDisposed = false;
+
+        /// <summary>
+        /// Pointer to the image.
+        /// </summary>
+        public IntPtr ImagePointer { get; }
+
+        /// <summary>
+        /// Width of the image.
+        /// </summary>
+        public int Width { get; }
+
+        /// <summary>
+        /// Height of the image.
+        /// </summary>
+        /// <value></value>
+        public int Height { get; }
+
+        /// <summary>
+        /// Internal image format.
+        /// </summary>
+        public StbiImageFormat Format { get; }
+
+        /// <summary>
+        /// True if the image is a floating point image.
+        /// </summary>
+        public bool IsFloat { get; }
+
+        private StbImage(IntPtr image, int x, int y, StbiImageFormat format, bool isFloat)
+        {
+            ImagePointer = image;
+            Width = x;
+            Height = y;
+            Format = format;
+            IsFloat = isFloat;
+        }
+
+        ~StbImage()
+        {
+            Dispose(false);
+        }
+
+        /// <summary>
+        /// Get a safe span to the image pointer.
+        /// </summary>
+        /// <typeparam name="T">The pixel type.</typeparam>
+        /// <returns>A span to the image data.</returns>
+        /// <exception cref="Exception">The image uses an unexpected image format.</exception>
+        public ReadOnlySpan<T> AsSpan<T>() where T : unmanaged
+        {
+            int sz = Format switch
+            {
+                StbiImageFormat.Grey => 1,
+                StbiImageFormat.GreyAlpha => 2,
+                StbiImageFormat.Rgb => 3,
+                StbiImageFormat.Rgba => 4,
+                _ => throw new Exception("unknown image format")
+            } * (IsFloat ? sizeof(float) : sizeof(byte));
+
+            return new ReadOnlySpan<T>((T*)ImagePointer, Width * Height * sz / sizeof(T));
+        }
+
+        /// <summary>
+        /// Write image to a PNG file.
+        /// </summary>
+        /// <param name="dest">The destination stream.</param>
+        /// <remarks>
+        /// Incurs a conversion cost if the image format is not a byte format. Affected by non-thread safe global options.
+        /// </remarks>
+        public void WritePng(Stream dest) => WritePng(AsSpan<byte>(), Width, Height, Format, dest, isFloat: IsFloat);
+
+        /// <summary>
+        /// Write image to a BMP file.
+        /// </summary>
+        /// <param name="dest">The destination stream.</param>
+        /// <remarks>
+        /// Incurs a conversion cost if the image format is not a byte format. Affected by non-thread safe global options.
+        /// </remarks>
+        public void WriteBmp(Stream dest) => WriteBmp(AsSpan<byte>(), Width, Height, Format, dest, isFloat: IsFloat);
+
+        /// <summary>
+        /// Write image to a TGA file.
+        /// </summary>
+        /// <param name="dest">The destination stream.</param>
+        /// <remarks>
+        /// Incurs a conversion cost if the image format is not a byte format. Ignores alpha channel. Affected by non-thread safe global options.
+        /// </remarks>
+        public void WriteTga(Stream dest) => WriteTga(AsSpan<byte>(), Width, Height, Format, dest, isFloat: IsFloat);
+
+        /// <summary>
+        /// Write image to a PNG file.
+        /// </summary>
+        /// <param name="dest">The destination stream.</param>
+        /// <remarks>
+        /// Incurs a conversion cost if the image format is not a float format. Affected by non-thread safe global options.
+        /// </remarks>
+        public void WriteHdr(Stream dest) => WriteHdr(AsSpan<byte>(), Width, Height, Format, dest, isFloat: IsFloat);
+
+        /// <summary>
+        /// Write image to a PNG file.
+        /// </summary>
+        /// <param name="dest">The destination stream.</param>
+        /// <param name="quality">The JPEG quality factor.</param>
+        /// <remarks>
+        /// Incurs a conversion cost if the image format is not a byte format. Ignores alpha channel. Affected by non-thread safe global options.
+        /// </remarks>
+        public void WriteJpg(Stream dest, int quality = 90) => WriteJpg(AsSpan<byte>(), Width, Height, Format, dest, quality: quality, isFloat: IsFloat);
+
+        public void Dispose() => Dispose(true);
+
+        private void Dispose(bool disposing)
+        {
+            if (isDisposed) return;
+
+            if (disposing)
+            {
+                GC.SuppressFinalize(this);
+            }
+
+            Stbi.image_free(ImagePointer.ToPointer());
+            isDisposed = true;
+        }
+
+        /// <summary>
+        /// Set to flip the y-axis of loaded images on load.
+        /// </summary>
+        public static bool FlipVerticallyOnLoad { set => Stbi.set_flip_vertically_on_load(value ? 1 : 0); }
+
+        /// <summary>
+        /// Set to flip the y-axis of saved images.
+        /// </summary>
+        public static bool FlipVerticallyOnSave { set => Stbi.flip_vertically_on_write(value ? 1 : 0); }
+
+        /// <summary>
+        /// Set to unpremultiply images on load.
+        /// </summary>
+        /// <remarks>
+        /// According to the stb_image documentation, only iPhone PNG images
+        /// can come with premultiplied alpha.
+        /// </remarks>
+        public static bool UnpremultiplyOnLoad { set => Stbi.set_unpremultiply_on_load(value ? 1 : 0); }
+
+        /// <summary>
+        /// Force a filter on PNG filter when saving.
+        /// </summary>
+        /// <remarks>
+        /// -1 for auto, 0 through 5 to pick a filter. Higher is more. Not thread safe.
+        /// </remarks>
+        public static int WriteForcePngFilter
+        {
+            get => Stbi.write_force_png_filter;
+            set
+            {
+                if (value < -1 || value > 5)
+                {
+                    throw new ArgumentOutOfRangeException(nameof(value), "The PNG filter must be in the range 0 to 5, or -1 for auto.");
+                }
+
+                Stbi.write_force_png_filter = value;
+            }
+        }
+
+        /// <summary>
+        /// Change the PNG compression level on save.
+        /// </summary>
+        /// <remarks>
+        /// Higher is more. Defaults to 8. Not thread safe.
+        /// </remarks>
+        public static int WritePngCompressionLevel
+        {
+            get => Stbi.write_png_compression_level;
+            set => Stbi.write_png_compression_level = value;
+        }
+
+        /// <summary>
+        /// Enable run length encoding on TGA images on save.
+        /// </summary>
+        /// <remarks>
+        /// Not thread safe.
+        /// </remarks>
+        public static bool WriteTgaEnableRLE
+        {
+            get => Stbi.write_tga_with_rle != 0;
+            set => Stbi.write_tga_with_rle = value ? 1 : 0;
+        }
+
+        /// <summary>
+        /// Try loading an image, without raising exceptions.
+        /// </summary>
+        /// <param name="image">The resulting image.</param>
+        /// <param name="stream">Source stream.</param>
+        /// <param name="format">The desired image format.</param>
+        /// <param name="asFloat">The buffer uses floating point pixels if true.</param>
+        /// <returns>True on success.</returns>
+        public static bool TryLoad([NotNullWhen(true)] out StbImage? image, Stream stream, StbiImageFormat format = StbiImageFormat.Default, bool asFloat = false)
+        {
+            int x, y, iFormat;
+            StbiStreamWrapper wrapper = new StbiStreamWrapper(stream, true);
+            stream.Position = 0;
+            IntPtr imagePtr;
+            fixed (stbi_io_callbacks* cb = &wrapper.Callbacks)
+            {
+                if (asFloat)
+                {
+                    imagePtr = (IntPtr)Stbi.loadf_from_callbacks(cb, null, &x, &y, &iFormat, (int)format);
+                }
+                else
+                {
+                    imagePtr = (IntPtr)Stbi.load_from_callbacks(cb, null, &x, &y, &iFormat, (int)format);
+                }
+            }
+
+            if (imagePtr != IntPtr.Zero)
+            {
+                image = new StbImage(imagePtr, x, y, (StbiImageFormat)iFormat, asFloat);
+                return true;
+            }
+            else
+            {
+                image = null;
+                return false;
+            }
+        }
+
+        /// <summary>
+        /// Try loading an image, without raising exceptions.
+        /// </summary>
+        /// <param name="image">The resulting image.</param>
+        /// <param name="span">Source memory span.</param>
+        /// <param name="format">The desired image format.</param>
+        /// <param name="asFloat">The buffer uses floating point pixels if true.</param>
+        /// <returns>True on success.</returns>
+        public static bool TryLoad([NotNullWhen(true)] out StbImage? image, ReadOnlySpan<byte> span, StbiImageFormat format = StbiImageFormat.Default, bool asFloat = false)
+        {
+            IntPtr imagePtr = IntPtr.Zero;
+            int x, y, iFormat;
+            fixed (byte *ptr = MemoryMarshal.AsBytes(span))
+            {
+                if (asFloat)
+                {
+                    imagePtr = (IntPtr)Stbi.loadf_from_memory(ptr, span.Length, &x, &y, &iFormat, (int)format);
+                }
+                else
+                {
+                    imagePtr = (IntPtr)Stbi.load_from_memory(ptr, span.Length, &x, &y, &iFormat, (int)format);
+                }
+
+                if (imagePtr != IntPtr.Zero)
+                {
+                    image = new StbImage(imagePtr, x, y, (StbiImageFormat)iFormat, asFloat);
+                    return true;
+                }
+                else
+                {
+                    image = null;
+                    return false;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Load an image.
+        /// </summary>
+        /// <param name="stream">The stream to load from.</param>
+        /// <param name="format">The desired image format.</param>
+        /// <param name="asFloat">The buffer uses floating point pixels if true.</param>
+        /// <returns>The image object.</returns>
+        public static StbImage Load(Stream stream, StbiImageFormat format = StbiImageFormat.Default, bool asFloat = false)
+        {
+            if (TryLoad(out StbImage? image, stream, format, asFloat))
+            {
+                return image;
+            }
+
+            string reason = Marshal.PtrToStringUTF8((IntPtr)Stbi.failure_reason())!;
+            throw new Exception($"Failed to load image: {reason}");
+        }
+
+        /// <summary>
+        /// Load an image.
+        /// </summary>
+        /// <param name="span">The span of memory to load from.</param>
+        /// <param name="format">The desired image format.</param>
+        /// <param name="asFloat">The buffer uses floating point pixels if true.</param>
+        /// <returns>The image object.</returns>
+        public static StbImage Load(ReadOnlySpan<byte> span, StbiImageFormat format = StbiImageFormat.Default, bool asFloat = false)
+        {
+            if (TryLoad(out StbImage? image, span, format, asFloat))
+            {
+                return image;
+            }
+
+            string reason = Marshal.PtrToStringUTF8((IntPtr)Stbi.failure_reason())!;
+            throw new Exception($"Failed to load image: {reason}");
+        }
+
+        /// <summary>
+        /// Peek image info from a stream.
+        /// </summary>
+        /// <param name="stream">The stream to peek into.</param>
+        /// <param name="width">Width of the image.</param>
+        /// <param name="height">Height of the image.</param>
+        /// <param name="format">The image format.</param>
+        /// <returns>True if the stream contained an image.</returns>
+        public static bool PeekInfo(Stream stream, out int width, out int height, out StbiImageFormat format)
+        {
+            int x, y, iFormat;
+            StbiStreamWrapper wrapper = new StbiStreamWrapper(stream, true);
+            int result;
+            stream.Position = 0;
+            fixed (stbi_io_callbacks* cb = &wrapper.Callbacks)
+            {
+                result = Stbi.info_from_callbacks(cb, null, &x, &y, &iFormat);
+            }
+
+            width = x;
+            height = y;
+            format = (StbiImageFormat)iFormat;
+
+            return result != 0;
+        }
+
+        /// <summary>
+        /// Peek image info from a span.
+        /// </summary>
+        /// <param name="span">The span to peek into.</param>
+        /// <param name="width">Width of the image.</param>
+        /// <param name="height">Height of the image.</param>
+        /// <param name="format">The image format.</param>
+        /// <returns>True if the stream contained an image.</returns>
+        public static bool PeekInfo<T>(ReadOnlySpan<T> span, out int width, out int height, out StbiImageFormat format) where T : unmanaged
+        {
+            fixed (byte* ptr = MemoryMarshal.AsBytes(span))
+            {
+                int x, y, iFormat;
+                int result = Stbi.info_from_memory(ptr, span.Length * sizeof(T), &x, &y, &iFormat);
+                width = x;
+                height = y;
+                format = (StbiImageFormat)iFormat;
+                return result != 0;
+            }
+        }
+
+        private static int Components(StbiImageFormat format) => format switch
+        {
+            StbiImageFormat.Grey => 1,
+            StbiImageFormat.GreyAlpha => 2,
+            StbiImageFormat.Rgb => 3,
+            StbiImageFormat.Rgba => 4,
+            _ => throw new ArgumentException("Expected a fully qualified format.")
+        };
+
+        private static byte[] ConvertFloatToByte<T>(ReadOnlySpan<T> source, int width, int height, int components)
+            where T : unmanaged
+        {
+            byte[] conversion = new byte[width * height * components];
+            ReadOnlySpan<float> dataAsFloat = MemoryMarshal.Cast<T, float>(source);
+
+            for (int i = 0; i<conversion.Length; i++)
+            {
+                conversion[i] = (byte) Math.Clamp(MathF.Round(dataAsFloat[i]* 255), 0, 255);
+            }
+
+            return conversion;
+        }
+
+        private static float[] ConvertByteToFloat<T>(ReadOnlySpan<T> source, int width, int height, int components)
+            where T : unmanaged
+        {
+            float[] conversion = new float[width * height * components];
+            ReadOnlySpan<byte> dataAsByte = MemoryMarshal.Cast<T, byte>(source);
+
+            for (int i = 0; i < conversion.Length; i++)
+            {
+                conversion[i] = Math.Clamp(dataAsByte[i]/255f, 0f, 1f);
+            }
+
+            return conversion;
+        }
+
+        /// <summary>
+        /// Write any image to a PNG file.
+        /// </summary>
+        /// <typeparam name="T">Any packed byte or float array structure.</typeparam>
+        /// <param name="data">Span of pixel data.</param>
+        /// <param name="width">Width of the pixel data in pixels.</param>
+        /// <param name="height">Height of the pixel data in pixels.</param>
+        /// <param name="format">Color format of the pixel data. Must not be <see cref="StbiImageFormat"/>.</param>
+        /// <param name="destination">The destination stream.</param>
+        /// <param name="isFloat">True if the pixel format in data is a floating point format.</param>
+        /// <remarks>
+        /// This will incur a conversion cost if the pixel format is not a byte format. Affected by global non-thread safe options.
+        /// </remarks>
+        public static void WritePng<T>(ReadOnlySpan<T> data, int width, int height, StbiImageFormat format, Stream destination, bool isFloat = false)
+            where T : unmanaged
+        {
+            int components = Components(format);
+            ReadOnlySpan<byte> source;
+            byte[]? conversion;
+
+            if (isFloat)
+            {
+                conversion = ConvertFloatToByte(data, width, height, components);
+                source = conversion;
+            }
+            else
+            {
+                source = MemoryMarshal.AsBytes(data);
+            }
+
+            StbiWriteStreamWrapper wrapper = new StbiWriteStreamWrapper(destination);
+
+            fixed (byte *ptr = source)
+                Stbi.write_png_to_func(wrapper, null, width, height, components, ptr, width * components);
+        }
+
+        /// <summary>
+        /// Write any image to a BMP file.
+        /// </summary>
+        /// <typeparam name="T">Any packed byte or float array structure.</typeparam>
+        /// <param name="data">Span of pixel data.</param>
+        /// <param name="width">Width of the pixel data in pixels.</param>
+        /// <param name="height">Height of the pixel data in pixels.</param>
+        /// <param name="format">Color format of the pixel data. Must not be <see cref="StbiImageFormat"/>.</param>
+        /// <param name="destination">The destination stream.</param>
+        /// <param name="isFloat">True if the pixel format in data is a floating point format.</param>
+        /// <remarks>
+        /// This will incur a conversion cost if the pixel format is not a byte format. Ignores the alpha channel. Affected by global non-thread safe options.
+        /// </remarks>
+        public static void WriteBmp<T>(ReadOnlySpan<T> data, int width, int height, StbiImageFormat format, Stream destination, bool isFloat = false)
+            where T : unmanaged
+        {
+            int components = Components(format);
+            ReadOnlySpan<byte> source;
+            byte[]? conversion;
+
+            if (isFloat)
+            {
+                conversion = ConvertFloatToByte(data, width, height, components);
+                source = conversion;
+            }
+            else
+            {
+                source = MemoryMarshal.AsBytes(data);
+            }
+
+            StbiWriteStreamWrapper wrapper = new StbiWriteStreamWrapper(destination);
+
+            fixed (byte* ptr = source)
+                Stbi.write_bmp_to_func(wrapper, null, width, height, components, ptr);
+        }
+
+        /// <summary>
+        /// Write any image to a TGA file.
+        /// </summary>
+        /// <typeparam name="T">Any packed byte or float array structure.</typeparam>
+        /// <param name="data">Span of pixel data.</param>
+        /// <param name="width">Width of the pixel data in pixels.</param>
+        /// <param name="height">Height of the pixel data in pixels.</param>
+        /// <param name="format">Color format of the pixel data. Must not be <see cref="StbiImageFormat"/>.</param>
+        /// <param name="destination">The destination stream.</param>
+        /// <param name="isFloat">True if the pixel format in data is a floating point format.</param>
+        /// <remarks>
+        /// This will incur a conversion cost if the pixel format is not a byte format. Affected by global non-thread safe options.
+        /// </remarks>
+        public static void WriteTga<T>(ReadOnlySpan<T> data, int width, int height, StbiImageFormat format, Stream destination, bool isFloat = false)
+            where T : unmanaged
+        {
+            int components = Components(format);
+            ReadOnlySpan<byte> source;
+            byte[]? conversion;
+
+            if (isFloat)
+            {
+                conversion = ConvertFloatToByte(data, width, height, components);
+                source = conversion;
+            }
+            else
+            {
+                source = MemoryMarshal.AsBytes(data);
+            }
+
+            StbiWriteStreamWrapper wrapper = new StbiWriteStreamWrapper(destination);
+
+            fixed (byte* ptr = source)
+                Stbi.write_tga_to_func(wrapper, null, width, height, components, ptr);
+        }
+
+        /// <summary>
+        /// Write any image to a PNG file.
+        /// </summary>
+        /// <typeparam name="T">Any packed byte or float array structure.</typeparam>
+        /// <param name="data">Span of pixel data.</param>
+        /// <param name="width">Width of the pixel data in pixels.</param>
+        /// <param name="height">Height of the pixel data in pixels.</param>
+        /// <param name="format">Color format of the pixel data. Must not be <see cref="StbiImageFormat"/>.</param>
+        /// <param name="destination">The destination stream.</param>
+        /// <param name="isFloat">True if the pixel format in data is a floating point format.</param>
+        /// <remarks>
+        /// This will incur a conversion cost if the pixel format is not a float format. Affected by global non-thread safe options.
+        /// </remarks>
+        public static void WriteHdr<T>(ReadOnlySpan<T> data, int width, int height, StbiImageFormat format, Stream destination, bool isFloat = false)
+            where T : unmanaged
+        {
+            int components = Components(format);
+            ReadOnlySpan<float> source;
+            float[]? conversion;
+
+            if (!isFloat)
+            {
+                conversion = ConvertByteToFloat(data, width, height, components);
+                source = conversion;
+            }
+            else
+            {
+                source = MemoryMarshal.Cast<T, float>(data);
+            }
+
+            StbiWriteStreamWrapper wrapper = new StbiWriteStreamWrapper(destination);
+
+            fixed (float* ptr = source)
+                Stbi.write_hdr_to_func(wrapper, null, width, height, components, ptr);
+        }
+
+        /// <summary>
+        /// Write any image to a PNG file.
+        /// </summary>
+        /// <typeparam name="T">Any packed byte or float array structure.</typeparam>
+        /// <param name="data">Span of pixel data.</param>
+        /// <param name="width">Width of the pixel data in pixels.</param>
+        /// <param name="height">Height of the pixel data in pixels.</param>
+        /// <param name="format">Color format of the pixel data. Must not be <see cref="StbiImageFormat"/>.</param>
+        /// <param name="destination">The destination stream.</param>
+        /// <param name="quality">The JPEG quality factor.</param>
+        /// <param name="isFloat">True if the pixel format in data is a floating point format.</param>
+        /// <remarks>
+        /// This will incur a conversion cost if the pixel format is not a byte format. Ignores the alpha channel. Affected by global non-thread safe options.
+        /// </remarks>
+        public static void WriteJpg<T>(ReadOnlySpan<T> data, int width, int height, StbiImageFormat format, Stream destination, int quality = 90, bool isFloat = false)
+            where T : unmanaged
+        {
+            int components = Components(format);
+            ReadOnlySpan<byte> source;
+            byte[]? conversion;
+
+            if (isFloat)
+            {
+                conversion = ConvertFloatToByte(data, width, height, components);
+                source = conversion;
+            }
+            else
+            {
+                source = MemoryMarshal.AsBytes(data);
+            }
+
+            StbiWriteStreamWrapper wrapper = new StbiWriteStreamWrapper(destination);
+
+            fixed (byte* ptr = source)
+                Stbi.write_jpg_to_func(wrapper, null, width, height, components, ptr, quality);
+        }
+    }
+}

ReFuel.StbImage/Stbi.Manual.cs

@@ -1,14 +1,16 @@
 using System;
-using System.IO;
-using System.Diagnostics;
 using System.Runtime.InteropServices;
 using System.Reflection;
 
-namespace ReFuel.Stb
+namespace ReFuel.Stb.Native
 {
+    /// <summary>
+    /// Direct access to the native STBI function calls.
+    /// </summary>
     public unsafe static partial class Stbi
     {
         private delegate void FailedAssertProc(byte *expression, byte *file, int line, byte *function);
+        private static IntPtr stbiHandle;
 
         private static readonly string[] LibraryNames = new string[] 
         {
@@ -29,22 +31,33 @@ namespace ReFuel.Stb
         static Stbi()
         {
             NativeLibrary.SetDllImportResolver(Assembly.GetExecutingAssembly(), Resolver);
+
+            // Dummy call to fail_reason so we have a handle to STBI.
+            failure_reason();
+
+            // Load global address pointers.
+
+            _tga_with_rle_ptr = (int*)NativeLibrary.GetExport(stbiHandle, "stbi_write_tga_with_rle");
+            _png_compression_level_ptr = (int*)NativeLibrary.GetExport(stbiHandle, "stbi_write_png_compression_level");
+            _force_png_filter_ptr = (int*)NativeLibrary.GetExport(stbiHandle, "stbi_write_force_png_filter");
         }
 
         private static IntPtr Resolver(string libraryName, Assembly assembly, DllImportSearchPath? searchPath)
         {
             if (libraryName != "stbi")
                 return IntPtr.Zero;
+            else if (stbiHandle != IntPtr.Zero)
+                return stbiHandle;
 
             foreach (string name in LibraryNames)
             {
-                if (NativeLibrary.TryLoad(name, assembly, searchPath, out IntPtr handle))
+                if (NativeLibrary.TryLoad(name, assembly, searchPath, out stbiHandle))
                 {
-                    return handle;
+                    return stbiHandle;
                 }
             }
 
-            return NativeLibrary.Load(libraryName);
+            return stbiHandle = NativeLibrary.Load(libraryName);
         }
     }
 }

ReFuel.StbImage/Stbi.cs

@@ -1,7 +1,7 @@
 using System;
 using System.Runtime.InteropServices;
 
-namespace ReFuel.Stb
+namespace ReFuel.Stb.Native
 {
     public enum StbiEnum : uint
     {

ReFuel.StbImage/StbiImageFormat.cs

@@ -1,5 +1,10 @@
+using ReFuel.Stb.Native;
+
 namespace ReFuel.Stb
 {
+    /// <summary>
+    /// Enumeration of supported STBI image formats.
+    /// </summary>
     public enum StbiImageFormat
     {
         Default     = (int)StbiEnum.STBI_default,

ReFuel.StbImage/StbiStreamWrapper.cs

@@ -0,0 +1,122 @@
+using ReFuel.Stb.Native;
+using System;
+using System.IO;
+using System.Runtime.InteropServices;
+
+namespace ReFuel.Stb
+{
+    /// <summary>
+    /// Pointer to STBI stream read function.
+    /// </summary>
+    /// <param name="userdata">User provided userdata pointer.</param>
+    /// <param name="buffer">C array to read into.</param>
+    /// <param name="count">Size of the C array in bytes.</param>
+    /// <returns>The number of bytes read from the stream.</returns>
+    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+    public unsafe delegate int StbiReadProc(void *userdata, byte* buffer, int count);
+
+    /// <summary>
+    /// Pointer to STBI stream skip function.
+    /// </summary>
+    /// <param name="userdata">User provided userdata pointer.</param>
+    /// <param name="count">Number of bytes to skip.</param>
+    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+    public unsafe delegate void StbiSkipProc(void *userdata, int count);
+
+    /// <summary>
+    /// Pointer to STBI stream end of file function.
+    /// </summary>
+    /// <param name="userdata">User provided userdata pointer.</param>
+    /// <returns>Non-zero value if the end of the stream has been reached.</returns>
+    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+    public unsafe delegate int StbiEofProc(void *userdata);
+
+    /// <summary>
+    /// An easy-to-use stream wrapper for use with STBI image load functions.
+    /// </summary>
+    public unsafe class StbiStreamWrapper : IDisposable
+    {
+        public readonly stbi_io_callbacks Callbacks;
+
+        private readonly Stream _stream;
+        private readonly bool _keepOpen;
+        private bool _isDisposed;
+
+        private StbiReadProc _readCb;
+        private StbiSkipProc _skipCb;
+        private StbiEofProc _eofCb;
+
+        public StbiStreamWrapper(Stream stream, bool keepOpen = false)
+        {
+            if (stream == null) throw new ArgumentNullException(nameof(stream));
+
+            _stream = stream;
+            _keepOpen = keepOpen;
+
+            _readCb = ReadCb;
+            _skipCb = SkipCb;
+            _eofCb = EofCb;
+
+            Callbacks = default;
+            Callbacks.read = Marshal.GetFunctionPointerForDelegate<StbiReadProc>(_readCb);
+            Callbacks.skip = Marshal.GetFunctionPointerForDelegate<StbiSkipProc>(_skipCb);
+            Callbacks.eof = Marshal.GetFunctionPointerForDelegate<StbiEofProc>(_eofCb);
+        }
+
+        private int ReadCb(void *userdata, byte* buffer, int count)
+        {
+            Span<byte> bytes = new Span<byte>(buffer, count);
+            return _stream.Read(bytes);
+        }
+
+        private void SkipCb(void *userdata, int count)
+        {
+            _stream.Seek(count, SeekOrigin.Current);
+        }
+
+        private int EofCb(void *userdata)
+        {
+            if (!_stream.CanRead || _stream.Position == _stream.Length)
+                return 1;
+            return 0;
+        }
+
+        public void Dispose()
+        {
+            if (_isDisposed) return;
+
+            if (!_keepOpen) _stream.Dispose();
+
+            _isDisposed = true;
+        }
+    }
+
+    /// <summary>
+    /// An easy to use stream wrapper for STBI image write functions.
+    /// </summary>
+    /// <remarks>Keep object alive for the duration of the write operation.</remarks>
+    public class StbiWriteStreamWrapper
+    {
+        private readonly Stream _stream;
+        private readonly StbiWriteProc _cb;
+
+        public IntPtr Callback { get; }
+
+        public StbiWriteStreamWrapper(Stream stream)
+        {
+            _stream = stream;
+            unsafe
+            {
+                _cb = WriteCb;
+            }
+            Callback = Marshal.GetFunctionPointerForDelegate(_cb);
+        }
+
+        private unsafe void WriteCb(void *context, void *data, int size)
+        {
+            _stream.Write(new ReadOnlySpan<byte>((byte*)data, size));
+        }
+
+        public static implicit operator IntPtr(in StbiWriteStreamWrapper wrapper) => wrapper.Callback;
+    }
+}

ReFuel.StbImage/StbiWrite.cs

@@ -0,0 +1,57 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace ReFuel.Stb.Native
+{
+    /// <summary>
+    /// Procedure to STBI image write function.
+    /// </summary>
+    /// <param name="context">User provided context pointer.</param>
+    /// <param name="data">C Array of data to write.</param>
+    /// <param name="size">Size of the C array in bytes.</param>
+    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+    public unsafe delegate void StbiWriteProc(void* context, void* data, int size);
+
+    public unsafe partial class Stbi
+    {
+        private static readonly int* _tga_with_rle_ptr;
+        private static readonly int* _png_compression_level_ptr;
+        private static readonly int* _force_png_filter_ptr;
+
+        public static int write_tga_with_rle
+        {
+            get => *_tga_with_rle_ptr;
+            set => *_tga_with_rle_ptr = value;
+        }
+
+        public static int write_png_compression_level
+        {
+            get => *_png_compression_level_ptr;
+            set => *_png_compression_level_ptr = value;
+        }
+
+        public static int write_force_png_filter
+        {
+            get => *_force_png_filter_ptr;
+            set => *_force_png_filter_ptr = value;
+        }
+
+        [DllImport("stbi", CallingConvention = CallingConvention.Cdecl, EntryPoint = "stbi_write_png_to_func")]
+        public static extern int write_png_to_func(IntPtr func, void* context, int w, int h, int comp, void* data, int stride_in_bytes);
+
+        [DllImport("stbi", CallingConvention = CallingConvention.Cdecl, EntryPoint = "stbi_write_bmp_to_func")]
+        public static extern int write_bmp_to_func(IntPtr func, void* context, int w, int h, int comp, void* data);
+
+        [DllImport("stbi", CallingConvention = CallingConvention.Cdecl, EntryPoint = "stbi_write_tga_to_func")]
+        public static extern int write_tga_to_func(IntPtr func, void* context, int w, int h, int comp, void* data);
+
+        [DllImport("stbi", CallingConvention = CallingConvention.Cdecl, EntryPoint = "stbi_write_hdr_to_func")]
+        public static extern int write_hdr_to_func(IntPtr func, void* context, int w, int h, int comp, void* data);
+
+        [DllImport("stbi", CallingConvention = CallingConvention.Cdecl, EntryPoint = "stbi_write_jpg_to_func")]
+        public static extern int write_jpg_to_func(IntPtr func, void* context, int w, int h, int comp, void* data, int quality);
+
+        [DllImport("stbi", CallingConvention = CallingConvention.Cdecl, EntryPoint = "stbi_flip_vertically_on_write")]
+        public static extern int flip_vertically_on_write(int value);
+    }
+}

StbImage.cs

@@ -1,234 +0,0 @@
-using System;
-using System.IO;
-using System.Runtime.InteropServices;
-
-namespace ReFuel.Stb
-{
-    /// <summary>
-    /// A class that encompasses all features of stb_image.h in a safe way.
-    /// </summary>
-    public unsafe class StbImage : IDisposable
-    {
-        private bool isDisposed = false;
-
-        /// <summary>
-        /// Pointer to the image.
-        /// </summary>
-        public IntPtr ImagePointer { get; }
-
-        /// <summary>
-        /// Width of the image.
-        /// </summary>
-        public int Width { get; }
-
-        /// <summary>
-        /// Height of the image.
-        /// </summary>
-        /// <value></value>
-        public int Height { get; }
-
-        /// <summary>
-        /// Internal image format.
-        /// </summary>
-        public StbiImageFormat Format { get; }
-        /// <summary>
-        /// True if the image is a floating point image.
-        /// </summary>
-        public bool IsFloat { get; }
-
-        private StbImage(IntPtr image, int x, int y, StbiImageFormat format, bool isFloat)
-        {
-            ImagePointer = image;
-            Width = x;
-            Height = y;
-            Format = format;
-            IsFloat = isFloat;
-        }
-
-        ~StbImage()
-        {
-            Dispose(false);
-        }
-
-        public void Dispose() => Dispose(true);
-
-        private void Dispose(bool disposing)
-        {
-            if (isDisposed) return;
-
-            if (disposing)
-            {
-                GC.SuppressFinalize(this);
-            }
-
-            Stbi.image_free(ImagePointer.ToPointer());
-            isDisposed = true;
-        }
-
-        /// <summary>
-        /// Set to flip the y-axis of loaded images on load.
-        /// </summary>
-        public static bool FlipVerticallyOnLoad { set => Stbi.set_flip_vertically_on_load(1); }
-
-        /// <summary>
-        /// Set to unpremultiply images on load.
-        /// </summary>
-        /// <remarks>
-        /// According to the stb_image documentation, only iPhone PNG images
-        /// can come with premultiplied alpha.
-        /// </remarks>
-        public static bool UnpremultiplyOnLoad { set => Stbi.set_unpremultiply_on_load(1); }
-
-        /// <summary>
-        /// Try loading an image, without raising exceptions.
-        /// </summary>
-        /// <param name="image">The resulting image.</param>
-        /// <param name="stream">Source stream.</param>
-        /// <param name="format">The desired image format.</param>
-        /// <returns>True on success.</returns>
-        public static bool TryLoad(out StbImage image, Stream stream, StbiImageFormat format = StbiImageFormat.Default, bool isFloat = false)
-        {
-            int x, y, iFormat;
-            StbiStreamWrapper wrapper = new StbiStreamWrapper(stream, true);
-            wrapper.CreateCallbacks(out stbi_io_callbacks cb);
-
-            stream.Position = 0;
-            IntPtr imagePtr;
-            if (isFloat)
-            {
-                imagePtr = (IntPtr)Stbi.loadf_from_callbacks(&cb, null, &x, &y, &iFormat, (int)format);
-            }
-            else
-            {
-                imagePtr = (IntPtr)Stbi.load_from_callbacks(&cb, null, &x, &y, &iFormat, (int)format);
-            }
-
-            if (imagePtr != IntPtr.Zero)
-            {
-                image = new StbImage(imagePtr, x, y, (StbiImageFormat)iFormat, isFloat);
-                return true;
-            }
-            else
-            {
-                image = null;
-                return false;
-            }
-        }
-
-        /// <summary>
-        /// Try loading an image, without raising exceptions.
-        /// </summary>
-        /// <param name="image">The resulting image.</param>
-        /// <param name="span">Source memory span.</param>
-        /// <param name="format">The desired image format.</param>
-        /// <returns>True on success.</returns>
-        public static bool TryLoad<T>(out StbImage image, ReadOnlySpan<T> span, StbiImageFormat format = StbiImageFormat.Default, bool isFloat = false)
-            where T : unmanaged
-        {
-            IntPtr imagePtr = IntPtr.Zero;
-            int x, y, iFormat;
-            fixed (byte *ptr = MemoryMarshal.AsBytes(span))
-            {
-                if (isFloat)
-                {
-                    imagePtr = (IntPtr)Stbi.loadf_from_memory(ptr, span.Length * sizeof(T), &x, &y, &iFormat, (int)format);
-                }
-                else
-                {
-                    imagePtr = (IntPtr)Stbi.load_from_memory(ptr, span.Length * sizeof(T), &x, &y, &iFormat, (int)format);
-                }
-
-                if (imagePtr != IntPtr.Zero)
-                {
-                    image = new StbImage(imagePtr, x, y, (StbiImageFormat)iFormat, isFloat);
-                    return true;
-                }
-                else
-                {
-                    image = null;
-                    return false;
-                }
-            }
-        }
-
-        /// <summary>
-        /// Load an image.
-        /// </summary>
-        /// <param name="stream">The stream to load from.</param>
-        /// <param name="format">The desired image format.</param>
-        /// <returns>The image object.</returns>
-        public static StbImage Load(Stream stream, StbiImageFormat format = StbiImageFormat.Default, bool isFloat = false)
-        {
-            if (TryLoad(out StbImage image, stream, format, isFloat))
-            {
-                return image;
-            }
-
-            string reason = Marshal.PtrToStringUTF8((IntPtr)Stbi.failure_reason());
-            throw new Exception($"Failed to load image: {reason}");
-        }
-
-        /// <summary>
-        /// Load an image.
-        /// </summary>
-        /// <param name="span">The span of memory to load from.</param>
-        /// <param name="format">The desired image format.</param>
-        /// <returns>The image object.</returns>
-        public static StbImage Load<T>(ReadOnlySpan<T> span, StbiImageFormat format = StbiImageFormat.Default, bool isFloat = false)
-            where T : unmanaged
-        {
-            if (TryLoad(out StbImage image, span, format, isFloat))
-            {
-                return image;
-            }
-
-            string reason = Marshal.PtrToStringUTF8((IntPtr)Stbi.failure_reason());
-            throw new Exception($"Failed to load image: {reason}");
-        }
-
-        /// <summary>
-        /// Peek image info from a stream.
-        /// </summary>
-        /// <param name="stream">The stream to peek into.</param>
-        /// <param name="width">Width of the image.</param>
-        /// <param name="height">Height of the image.</param>
-        /// <param name="format">The image format.</param>
-        /// <returns>True if the stream contained an image.</returns>
-        public static bool PeekInfo(Stream stream, out int width, out int height, out StbiImageFormat format)
-        {
-            int x, y, iFormat;
-            StbiStreamWrapper wrapper = new StbiStreamWrapper(stream, true);
-            wrapper.CreateCallbacks(out stbi_io_callbacks cb);
-
-            stream.Position = 0;
-            int result = Stbi.info_from_callbacks(&cb, null, &x, &y, &iFormat);
-
-            width = x;
-            height = y;
-            format = (StbiImageFormat)iFormat;
-
-            return result != 0;
-        }
-
-        /// <summary>
-        /// Peek image info from a span.
-        /// </summary>
-        /// <param name="span">The span to peek into.</param>
-        /// <param name="width">Width of the image.</param>
-        /// <param name="height">Height of the image.</param>
-        /// <param name="format">The image format.</param>
-        /// <returns>True if the stream contained an image.</returns>
-        public static bool PeekInfo<T>(ReadOnlySpan<T> span, out int width, out int height, out StbiImageFormat format) where T : unmanaged
-        {
-            fixed (byte* ptr = MemoryMarshal.AsBytes(span))
-            {
-                int x, y, iFormat;
-                int result = Stbi.info_from_memory(ptr, span.Length * sizeof(T), &x, &y, &iFormat);
-                width = x;
-                height = y;
-                format = (StbiImageFormat)iFormat;
-                return result != 0;
-            }
-        }
-    }
-}

StbiStreamWrapper.cs

@@ -1,68 +0,0 @@
-using System;
-using System.IO;
-using System.Runtime.InteropServices;
-
-namespace ReFuel.Stb
-{
-    public unsafe delegate int StbiReadProc(void *userdata, byte* buffer, int count);
-    public unsafe delegate void StbiSkipProc(void *userdata, int count);
-    public unsafe delegate int StbiEofProc(void *userdata);
-
-    public unsafe class StbiStreamWrapper : IDisposable
-    {
-        private Stream _stream;
-        private bool _keepOpen;
-        private bool _isDisposed;
-
-        private StbiReadProc _readCb;
-        private StbiSkipProc _skipCb;
-        private StbiEofProc _eofCb;
-
-        public StbiStreamWrapper(Stream stream, bool keepOpen = false)
-        {
-            if (stream == null) throw new ArgumentNullException(nameof(stream));
-
-            _stream = stream;
-            _keepOpen = keepOpen;
-
-            _readCb = ReadCb;
-            _skipCb = SkipCb;
-            _eofCb = EofCb;
-        }
-
-        public void CreateCallbacks(out stbi_io_callbacks cb)
-        {
-            cb = default;
-            cb.read = Marshal.GetFunctionPointerForDelegate<StbiReadProc>(_readCb);
-            cb.skip = Marshal.GetFunctionPointerForDelegate<StbiSkipProc>(_skipCb);
-            cb.eof = Marshal.GetFunctionPointerForDelegate<StbiEofProc>(_eofCb);
-        }
-
-        private int ReadCb(void *userdata, byte* buffer, int count)
-        {
-            Span<byte> bytes = new Span<byte>(buffer, count);
-            return _stream.Read(bytes);
-        }
-
-        private void SkipCb(void *userdata, int count)
-        {
-            _stream.Seek(count, SeekOrigin.Current);
-        }
-
-        private int EofCb(void *userdata)
-        {
-            if (!_stream.CanRead || _stream.Position == _stream.Length)
-                return 1;
-            return 0;
-        }
-
-        public void Dispose()
-        {
-            if (_isDisposed) return;
-
-            if (!_keepOpen) _stream.Dispose();
-
-            _isDisposed = true;
-        }
-    }
-}

build_native.sh

@@ -1,4 +1,4 @@
 #!/bin/bash
 cd $(dirname "$0")
 ./docker-cross-compiler/sh/build_native.sh .
-dotnet build
+dotnet build -c Release

rf_stbi.h

@@ -7,6 +7,7 @@
 #define STBI_NO_THREAD_LOCALS 1
 #include "stb/stb_image.h"
 
+#define STBIWDEF RFEXTERN
 #define STBI_WRITE_NO_STDIO 1
 #include "stb/stb_image_write.h"