Advanced Configuration

WebPEncoderConfig Fluent API

WebPEncoderConfig provides a fluent builder for all libwebp encoding parameters:

using Imazen.WebP;

var config = new WebPEncoderConfig()
    .SetQuality(85)           // Lossy quality 0–100
    .SetMethod(6)             // Compression effort 0–6
    .SetSharpYuv()            // Better chroma downsampling
    .SetSnsStrength(50)       // Spatial noise shaping 0–100
    .SetFilterStrength(20)    // Deblocking filter 0–100
    .SetAlphaQuality(90)      // Alpha quality 0–100
    .SetMultiThreaded()       // Multi-threaded encoding
    .SetExact();              // Preserve RGB under transparent areas

All Available Settings

Method	Description	Range
`SetQuality(float)`	Lossy quality level	0–100
`SetLossless(bool)`	Enable lossless mode	—
`SetLosslessPreset(int)`	Lossless preset level	0–9
`SetMethod(int)`	Compression speed/quality tradeoff	0–6
`SetNearLossless(int)`	Near-lossless preprocessing	0–100
`SetTargetSize(int)`	Target file size in bytes	—
`SetTargetPSNR(float)`	Target PSNR in dB	—
`SetMultiThreaded(bool)`	Multi-threaded encoding	—
`SetSnsStrength(int)`	Spatial noise shaping	0–100
`SetFilterStrength(int)`	Deblocking filter	0–100
`SetAlphaQuality(int)`	Alpha channel quality	0–100
`SetImageHint(WebPImageHint)`	Content type hint	—
`SetExact(bool)`	Preserve RGB under transparency	—
`SetSharpYuv(bool)`	Sharp RGB→YUV conversion	—

Validation

Validate your configuration before encoding:

if (!config.Validate())
    throw new ArgumentException("Invalid encoder config");

Native Config Access

For direct P/Invoke scenarios, get the underlying WebPConfig struct:

WebPConfig nativeConfig = config.GetNativeConfig();

ABI Version Checks

The library automatically validates ABI compatibility when the native library is first loaded. You can also check manually:

using Imazen.WebP;

// Throws NotSupportedException if incompatible
AbiVersionCheck.ValidateOrThrow();

// Get version string
string version = AbiVersionCheck.GetVersionString();
// e.g. "decoder=1.5.0, encoder=1.5.0"

// Individual version strings
string decoderVer = SimpleDecoder.GetDecoderVersion();
string encoderVer = SimpleEncoder.GetEncoderVersion();

Native Library Loading

Imazen.WebP automatically locates and loads native libraries using this search order:

runtimes/{rid}/native/ — standard .NET runtime package location
Architecture subdirectory (x64/, arm64/, etc.)
Application base directory

The library resolves the correct platform and architecture at runtime via RuntimeInformation. Supported platforms:

Windows: webp.dll, webpdemux.dll, webpmux.dll
Linux: libwebp.so, libwebpdemux.so, libwebpmux.so
macOS: libwebp.dylib, libwebpdemux.dylib, libwebpmux.dylib

If loading fails, a detailed DllNotFoundException is thrown with diagnostics showing all paths attempted.

WebPInfo — Image Probing

Query image metadata without full decoding:

using Imazen.WebP;

byte[] data = File.ReadAllBytes("image.webp");

// Quick size check (returns false for invalid data)
if (WebPInfo.TryGetSize(data, out int width, out int height))
    Console.WriteLine($"{width}x{height}");

// Full bitstream features
WebPImageInfo info = WebPInfo.GetImageInfo(data);
// info.Width, info.Height
// info.HasAlpha — true if image has transparency
// info.HasAnimation — true if animated WebP
// info.Format — 0=undefined/mixed, 1=lossy, 2=lossless

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