PhotoSauce.MagicScaler

APNG decoding is enabled by default. However, APNG encoding is disabled by default due to an intermittent memory corruption bug in APNG-patched libpng.

To enable APNG encoding for testing, set the PhotoSauce.NativeCodecs.Libpng.EnableApngEncode switch at application startup using AppContext.SetSwitch or via your runtimeconfig.json file.

MagicScaler uses several advanced techniques to ensure superior resizing quality compared to standard libraries:

1. Linear Light Processing: It performs resampling in linear light, which preserves highlights and prevents color shifts during blending.
2. High-Quality Resampling: It defaults to high-quality resampling algorithms to prevent blurriness.
3. Post-Resizing Sharpening: It automatically applies a sharpening step to compensate for the natural blurring that occurs during the resizing process.

To enable GIF support via Giflib, call the UseGiflib extension method within your CodecManager.Configure action during application startup.

Note: By default, this plugin will remove or replace the built-in Windows GIF codec if it is detected in the pipeline.

using PhotoSauce.MagicScaler;
using PhotoSauce.NativeCodecs.Giflib;

CodecManager.Configure(codecs => {
    codecs.UseGiflib();
});

To run PhotoSauce.WebRSize, your hosting environment must meet the following criteria:

• IIS Version: IIS 7 or higher.
• ASP.NET Version: ASP.NET 4.6.1 or higher (compatible with WebForms or MVC).
• App Pool Mode: The host Application Pool must be running in Integrated Pipeline Mode.

By default, WebRSize requests are ineligible for http.sys kernel caching because they use query strings and URL rewriting. To achieve performance parity with static image files, you must explicitly configure a kernelCachePolicy in your IIS configuration.

This allows processed images to be served directly from the kernel cache once they have been written to the disk cache.

To enable this for .jpg files, add a profile to your web.config using the following configuration:

<system.webServer>
  <caching>
    <profiles>
      <add extension=".jpg" kernelCachePolicy="CacheUntilChange" location="Any" />
    </profiles>
  </caching>
</system.webServer>

The WebRSizeModule (an IHttpModule) manages processing and caching. Because image file extensions are often mapped to the unmanaged IIS static file handler, the module might not automatically receive event notifications via PreApplicationStartMethodAttribute.

To ensure the module intercepts requests, use one of these two methods:

1. Explicit Module Registration (Recommended)

Register the module explicitly in the system.webServer section and omit the preCondition attribute. This ensures the module sees all requests, managed or not.

<system.webServer>
  <modules>
    <add name="WebRSize" type="PhotoSauce.WebRSize.WebRSizeModule" />
  </modules>
</system.webServer>

2. Explicit Handler Mapping

Map specific image extensions to a managed IHttpHandler (like System.Web.StaticFileHandler). This allows the self-registered module to intercept the requests.

PhotoSauce.NativeCodecs.Libpng is a MagicScaler plugin that wraps the libpng native codec. It provides PNG support for non-Windows platforms or enhanced capabilities on Windows.

Requirements

• A compatible native binary must be present. The NuGet package includes binaries for:
  • Windows: x86, x64, and ARM64
  • Linux: glibc x64 and ARM64
• If you need to build for an unsupported platform, you must use a custom build of libpng. A specialized vcpkg port is available in the PhotoSauce GitHub repository under build/vcpkg/ports/pspng.

<!-- No installation command provided in source, but refers to NuGet package -->

To use this plugin, a compatible native binary must be present. The NuGet package provides native binaries for the following platforms:

• Windows: x86, x64, and ARM64
• Linux: glibc x64 and ARM64

This plugin is primarily used to provide GIF support on non-Windows platforms where the auto-discoverable Windows GIF codec is unavailable.

WebRSize requires explicit opt-in for image folders and a registered ConfigSection. Note that WebRSize currently only works with ASP.NET hosted with IIS Integrated Pipeline Mode; ASP.NET Core support is pending.

To enable WebRSize, first register the webrsize section in your web.config:

<configSections>
  <section name="webrsize" type="PhotoSauce.WebRSize.WebRSizeSection" />
</configSections>

Then, provide a minimal configuration specifying a diskCache path and at least one imageFolders entry. The diskCache folder must exist and the App Pool identity must have write access to it.

<configSections>
  <section name="webrsize" type="PhotoSauce.WebRSize.WebRSizeSection" />
</configSections>

<webrsize>
  <diskCache path="/webrsizecache" />
  <imageFolders>
    <add name="images" path="/images/" />
  </imageFolders>
</webrsize>