Gets the logical and ink extents of a glyph within a font.
The coordinate system for each rectangle has its origin at the base line and horizontal origin of the character with increasing coordinates
extending to the right and down. The macros
PANGO_RBEARING can be used to convert from the extents rectangle to more traditional font metrics. The units of the rectangles are in
1/PANGO_SCALE of a device unit.
If this is null, this function gracefully sets some sane values in the output variables and returns.
the glyph index
rectangle used to store the extents of the glyph as drawn
rectangle used to store the logical extents of the glyph