https://learn.microsoft.com/es-es/dotnet/api/system.drawing.drawing2d.pathgradientbrush.blend?view=netframework-4.8.1
PathGradientBrush.Blend Property (System.Drawing.Drawing2D) | Microsoft Learn
Gets or sets a Blend that specifies positions and factors that define a custom falloff for the gradient.
property systemblenddrawingmicrosoftlearn
https://www.syncfusion.com/feedback/64330/need-to-provide-pathgradientbrush-support-in-pdf-library
Need to provide PathGradientBrush support in PDF library in ASP.NET Core | Feedback Portal
Check out the feature request in ASP.NET Core - PDF - Need to provide PathGradientBrush support in PDF library.