XTextExtents(3X11) MIT X11R4 XTextExtents(3X11)
Name
XTextExtents, XTextExtents16, XQueryTextExtents, XQueryTextExtents16 - compute or query text extents
Syntax
XTextExtents(font_struct, string, nchars, direction_return, font_ascent_return, font_descent_return, overall_return)
XFontStruct *font_struct;
char *string;
int nchars;
int *direction_return;
int *font_ascent_return, *font_descent_return;
XCharStruct *overall_return;
XTextExtents16(font_struct, string, nchars, direction_return, font_ascent_return, font_descent_return, overall_return)
XFontStruct *font_struct;
XChar2b *string;
int nchars;
int *direction_return;
int *font_ascent_return, *font_descent_return;
XCharStruct *overall_return;
XQueryTextExtents(display, font_ID, string, nchars, direction_return, font_ascent_return, font_descent_return, overall_return)
Display *display;
XID font_ID;
char *string;
int nchars;
int *direction_return;
int *font_ascent_return, *font_descent_return;
XCharStruct *overall_return;
XQueryTextExtents16(display, font_ID, string, nchars, direction_return, font_ascent_return, font_descent_return, overall_return)
Display *display;
XID font_ID;
XChar2b *string;
int nchars;
int *direction_return;
int *font_ascent_return, *font_descent_return;
XCharStruct *overall_return;
Arguments
direction_return
Returns the value of the direction hint or
display Specifies the connection to the X server.
font_ID Specifies either the font ID or the ID that contains the font.
font_ascent_return
Returns the font ascent.
font_descent_return
Returns the font descent.
font_struct
Specifies a pointer to the structure.
nchars Specifies the number of characters in the character string.
string Specifies the character string.
overall_return
Returns the overall size in the specified structure.
Description
The and functions perform the size computation locally and, thereby, avoid the round-trip overhead of and Both functions return an struc-
ture, whose members are set to the values as follows.
The ascent member is set to the maximum of the ascent metrics of all characters in the string. The descent member is set to the maximum of
the descent metrics. The width member is set to the sum of the character-width metrics of all characters in the string. For each charac-
ter in the string, let W be the sum of the character-width metrics of all characters preceding it in the string. Let L be the left-side-
bearing metric of the character plus W. Let R be the right-side-bearing metric of the character plus W. The lbearing member is set to the
minimum L of all characters in the string. The rbearing member is set to the maximum R.
For fonts defined with linear indexing rather than 2-byte matrix indexing, each structure is interpreted as a 16-bit number with byte1 as
the most-significant byte. If the font has no defined default character, undefined characters in the string are taken to have all zero
metrics.
The and functions return the bounding box of the specified 8-bit and 16-bit character string in the specified font or the font contained in
the specified GC. These functions query the X server and, therefore, suffer the round-trip overhead that is avoided by and Both functions
return a structure, whose members are set to the values as follows.
The ascent member is set to the maximum of the ascent metrics of all characters in the string. The descent member is set to the maximum of
the descent metrics. The width member is set to the sum of the character-width metrics of all characters in the string. For each charac-
ter in the string, let W be the sum of the character-width metrics of all characters preceding it in the string. Let L be the left-side-
bearing metric of the character plus W. Let R be the right-side-bearing metric of the character plus W. The lbearing member is set to the
minimum L of all characters in the string. The rbearing member is set to the maximum R.
For fonts defined with linear indexing rather than 2-byte matrix indexing, each structure is interpreted as a 16-bit number with byte1 as
the most-significant byte. If the font has no defined default character, undefined characters in the string are taken to have all zero
metrics.
Characters with all zero metrics are ignored. If the font has no defined default_char, the undefined characters in the string are also
ignored.
and can generate and errors.
Diagnostics
A value for a Font or GContext argument does not name a defined Font.
A value for a GContext argument does not name a defined GContext.
See Also
XLoadFont(3X11), XTextWidth(3X11)
X Window System: The Complete Reference, Second Edition, Robert W. Scheifler and James Gettys
XTextExtents(3X11)