man XFontSetExtents (Fonctions bibliothèques) - XFontSetExtents structure
NAME
XFontSetExtents - XFontSetExtents structure
STRUCTURES
The structure contains:
typedef struct { XRectangle max_ink_extent; / over all drawable characters */ XRectangle max_logical_extent; / over all drawable characters */ } XFontSetExtents;
The structures used to return font set metrics are the usual Xlib screen-oriented rectangles with x, y giving the upper left corner, and width and height always positive.
The max_ink_extent member gives the maximum extent, over all drawable characters, of the rectangles that bound the character glyph image drawn in the foreground color, relative to a constant origin. See and for detailed semantics.
The max_logical_extent member gives the maximum extent, over all drawable characters, of the rectangles that specify minimum spacing to other graphical features, relative to a constant origin. Other graphical features drawn by the client, for example, a border surrounding the text, should not intersect this rectangle. The max_logical_extent member should be used to compute minimum interline spacing and the minimum area that must be allowed in a text field to draw a given number of arbitrary characters.
Due to context-dependent rendering, appending a given character to a string may change the string's extent by an amount other than that character's individual extent.