Text Rotation in degrees.
When this value is from 0 to 90 then this is the rotation degrees in the up direction.
When this value is from 91 to 180 then this is a rotation in the down direction. 91 means -1 degree rotation, 92 means -2 degrees, and so on until 180 which means -90 degrees.
255 is vertical text.
Other values are invalid.