I have searched around and found that most of the answers convert a WriteableBitmap to a System.Drawing.Bitmap. I am currently thinking of using WriteableBitmapEx's Blitz() function to overlay a bitmap with text onto the existing bitmap, but I don't really find functions that return WriteableBitmap.
Is there a easy way to draw text?
I managed to use the WriteableBitmapEx DrawString() method to achieve this directly.
Unfortunately it is not inside the Nuget Packages so it has to be compiled from the source of another project:
https://writeablebitmapex.codeplex.com/discussions/579148
https://fastwpfgrid.codeplex.com/SourceControl/latest#WriteableBitmapEx/LetterGlyphTool.cs