Image Decoding

CodeGlyphX includes a built-in decoder for reading QR codes and barcodes from images.

Basic Usage

using CodeGlyphX;

// Decode from file
byte[] imageBytes = File.ReadAllBytes("qrcode.png");

if (QrImageDecoder.TryDecodeImage(imageBytes, out var result))
{
    Console.WriteLine($"Decoded: {result.Text}");
    Console.WriteLine($"Format: {result.BarcodeFormat}");
}

// Decode from stream
using var stream = File.OpenRead("barcode.png");
var decodeResult = QrImageDecoder.DecodeImage(stream);

Supported Formats for Decoding

• Images: PNG, JPEG, WebP, BMP, GIF, TIFF, PPM/PGM/PBM/PAM, TGA, ICO/CUR, XBM, XPM
• QR Codes: Standard QR, Micro QR
• 1D Barcodes: Code 128, Code 39/93, EAN/UPC, ITF, Codabar, MSI, Telepen, Plessey, more
• 2D Matrix: Data Matrix, PDF417, Aztec

Known Gaps (Decoding)

• AVIF, HEIC, JPEG2000
• ImageReader.DecodeRgba32 returns the first GIF/WebP frame; use ImageReader.DecodeGifAnimationFrames / DecodeWebpAnimationFrames (or GifReader/WebpReader) for animation frames
• ImageReader.DecodeRgba32 returns the first TIFF page; use ImageReader.TryDecodeTiffPagesRgba32 (or TiffReader.DecodePagesRgba32) for multi-page
• PDF decode supports image-only PDFs with embedded JPEG/Flate; PS decode still needs rasterization

Format Corpus (Optional)

We maintain external image samples to validate edge cases (PNG/TIFF suites, packed bit-depths, interlace, etc.). These are not stored in the repo.

// Download the image format corpus
pwsh Build/Download-ImageSamples.ps1

// Download external barcode/QR samples
pwsh Build/Download-ExternalSamples.ps1

Handling Multiple Results

// Decode all barcodes in an image
var results = QrImageDecoder.DecodeAllImages(imageBytes);

foreach (var barcode in results)
{
    Console.WriteLine($"{barcode.BarcodeFormat}: {barcode.Text}");
}

Diagnostics

using CodeGlyphX;

if (!CodeGlyph.TryDecodeImage(imageBytes, out var decoded, out var diagnostics, options: null))
{
    Console.WriteLine(diagnostics.FailureReason);
    Console.WriteLine(diagnostics.Failure);
}