TextHeight in RichTextBox

Question

Hi all,

I made a custom column that can read RTF so that colors and fonts can be used.
Now that this is done, I encountered a problem.
The rows in this datagridview can be minimized (standardheight) or maximized (height of the text in the rtf cell).
But when using different fonts and images in this rtf cell, it all goes wrong.
Does anyone have any idea on how to get the correct height?

Been stuck in this for a few days now.

Kind regards

Coupé Dries