This property is applied only to text written in a horizontal writingMode.
The glyph orientation affects the amount that the current text position advances as each glyph is rendered. When the reference orientation direction is horizontal and the glyphOrientationHorizontal results in an orientation angle that is a multiple of 180 degrees, the current text position is incremented according to the horizontal metrics of the glyph. Otherwise, if the glyphOrientationHorizontal results in an orientation angle that is not a multiple of 180 degrees, the current text position is incremented according to the vertical metrics of the glyph.
glyph-orientation-horizontal: angle | inherit
- Scalable Vector Graphics: Text, Section 10.7.2
Microsoft Developer Network: [Windows Internet Explorer API reference Article]