Sets the width scale factor of the text boundary (DXF 41). This factor influences only on the text width and is used for scaling of letters and spaces when the height is constant. A value less than 1.0 condenses the text. A value greater than 1.0 expandes the text. The initial value is 1.0 by default. 

Example of Working with the Text Style Record Object 

Specific Properties of Text Styles 

OdDbTextStyleTableRecord::xScale() method