PeachPDF
PeachPDF.PdfGenerateConfig
PdfGenerateConfig.JxlPassthrough Property
<b>Experimental, off by default.</b> When true and PdfVersion is
Pdf20, an opaque, upright, non-animated gray or RGB JPEG XL image is embedded
as its original bytes with the /JXLDecode filter instead of being decoded and recompressed. There is no
published PDF filter for JPEG XL yet: the name and layout follow the only open-source design so far (an
experimental PDFium decoder), so no shipping PDF reader opens such a file today. A JPEG XL with alpha, animation
or CMYK always takes the normal raster path. Ignored for other PdfVersion values, and under
Lossy (which asks for JPEG re-encoding).
public bool JxlPassthrough { get; set; }