A set of values that define the size, position and spacing of a glyph when performing text layout.
| height | The height of the glyph. | 
| horizontalAdvance | The horizontal distance to increase (left to right) or decrease (right to left) the drawing position relative to the origin of the text element. | 
| horizontalBearingX | The horizontal distance from the current drawing position (origin) relative to the element's left bounding box edge (bbox). | 
| horizontalBearingY | The vertical distance from the current baseline relative to the element's top bounding box edge (bbox). | 
| width | The width of the glyph. | 
| GlyphMetrics | Constructs a new GlyphMetrics structure. |