d2phap/ImageGlass · error · Exception

Can't configure preset

Error message

Can't configure preset

What it means

Thrown by the advanced EncodeLossy(Bitmap, int, int, bool) when LibWebp.WebPConfigInit returns 0. WebPConfigInit initializes a WebPConfig struct with a preset; returning 0 means the ABI/version handshake with the native libwebp failed or the preset is invalid. Effectively: the wrapper cannot initialize the encoder configuration.

Solutions

1. Verify the bundled libwebp binary matches the process architecture (x64 DLL for x64 process) and loads without error.
2. Check WebPWrapper.GetVersion() returns a sane libwebp version before encoding.
3. Ship the libwebp build that matches the wrapper's expected ABI; rebuild the wrapper against your libwebp if needed.
4. Fall back to the simple EncodeLossy(bmp, quality) API which does not require WebPConfigInit.

Example fix

// before
var bytes = webp.EncodeLossy(bmp, quality, speed);

// after
if (Version.Parse(WebPWrapper.GetVersion()).Major < 1)
    throw new InvalidOperationException("Incompatible libwebp; use simple encoder.");
var bytes = webp.EncodeLossy(bmp, quality); // simple API, no WebPConfigInit

var ver = WebPWrapper.GetVersion();
if (string.IsNullOrEmpty(ver) || Version.Parse(ver).Major < 1)
    throw new InvalidOperationException("libwebp not loaded or too old for advanced encode.");

byte[] bytes;
try { bytes = webp.EncodeLossy(bmp, quality, speed); }
catch (Exception ex) when (ex.Message == "Can't configure preset")
{ bytes = webp.EncodeLossy(bmp, quality); /* simple API fallback */ }

When it happens

Trigger: Calling the three-argument EncodeLossy(bmp, quality, speed) where WebPConfigInit(WEBP_PRESET_DEFAULT, 75) returns 0. Most often caused by a libwebp DLL whose version/ABI does not match the wrapper's P/Invoke signatures, or a missing/broken native binary.

Common situations: Deploying with the wrong libwebp.dll build (x86 vs x64, debug vs release); a corrupted or truncated DLL; calling encode before the native library is loaded successfully; version skew between the C# wrapper and the bundled libwebp.

Related errors

• Can't config preset
• Bad configuration parameters
• Bitmap's dimension is too large. Max is
• Can't configure lossless preset
• Can't encode WebP

AI-assisted analysis of d2phap/ImageGlass@4a3c4fecef (2026-08-13). Data as JSON: /api/errors/f80cd97a4905f468. Report an issue: GitHub.

Appendix: source

Thrown at v9/Components/ImageGlass.WebP/WebPWrapper.cs:447

            if (unmanagedData != IntPtr.Zero)
                LibWebp.WebPFree(unmanagedData);
        }
    }


    /// <summary>Lossy encoding bitmap to WebP (Advanced encoding API)</summary>
    /// <param name="bmp">Bitmap with the image</param>
    /// <param name="quality">Between 0 (lower quality, lowest file size) and 100 (highest quality, higher file size)</param>
    /// <param name="speed">Between 0 (fastest, lowest compression) and 9 (slower, best compression)</param>
    /// <returns>Compressed data</returns>
    public byte[] EncodeLossy(Bitmap bmp, int quality, int speed, bool info = false)
    {
        // Initialize configuration structure
        var config = new WebPConfig();

        // Set compression parameters
        if (LibWebp.WebPConfigInit(ref config, WebPPreset.WEBP_PRESET_DEFAULT, 75) == 0)
            throw new Exception("Can't configure preset");

        // Add additional tuning:
        config.method = speed;
        if (config.method > 6) config.method = 6;

        config.quality = quality;
        config.autofilter = 1;
        config.pass = speed + 1;
        config.segments = 4;
        config.partitions = 3;
        config.thread_level = 1;
        config.alpha_quality = quality;
        config.alpha_filtering = 2;
        config.use_sharp_yuv = 1;

        if (LibWebp.WebPGetDecoderVersion() > 1082) // Old version does not support preprocessing 4
        {
            config.preprocessing = 4;

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