void set_fixed_height_from_font(int number_of_rows);

Sets the height of the renderer to a value determined by its current font and y_pad values. number_of_rows specifies the number of rows of text each cell renderer should be allocated. If number_of_rows is -1, the fixed height will be unset and the height will be determined by the properties again.

This method is unflexible, and should really only be used if calculating the size of a cell is too slow (ie, a massive number of cells displayed).