If the extent can not be obtained (e.g. missing support), all of x, y, width, height are set to -1.
Get the bounding box containing the glyph representing the character at a particular text offset.
The offset of the text character for which bounding information is required.
Pointer for the x coordinate of the bounding box
Pointer for the y coordinate of the bounding box
Pointer for the width of the bounding box
Pointer for the height of the bounding box
specify whether coordinates are relative to the screen or widget window