add overview for text-extents section

Signed-off-by: Thomas E. Dickey <dickey@invisible-island.net>

1 files changed, 19 insertions, 3 deletions

diff --git a/man/Xft.man b/man/Xft.man
index 9d6b68b..afb1fb0 100644
--- a/man/Xft.man
+++ b/man/Xft.man
@@ -646,7 +646,7 @@ Example:
                         NULL);
 .QE
 .IP
-This opens the \(lqcharter\(rq font at 12 points.
+This opens the \*(``charter\*('' font at 12 points.
 The point size is automatically converted to the correct pixel size based
 on the resolution of the monitor.
 .PP
@@ -697,7 +697,15 @@ and
 .B FcResult
 data types are defined by the Fontconfig library.
 .\" *************************************************************************
-.SS "Determining the Pixel Extents of a Text String"
+.SS "Determining Text Extents"
+.B Xft
+provides several functions for determining the required height and width
+for displaying a text-string.
+After accounting for the
+.IR offset ,
+in cases where the string will be shifted up, down, left or right,
+these numbers are referred to as
+.IR Itext extents .
 .PS
 \fBvoid\fP \fBXftTextExtents8\fP (
 	\fBDisplay\fP	*\fIdpy\fP,
@@ -835,7 +843,7 @@ data type is defined by the X Rendering Extension library.
 	\fBXGlyphInfo\fP	*\fIextents\fP);
 .PE
 Also used internally by the
-.BR XftTextExtents *
+.BR XftTextExtents *()
 functions,
 .B XftGlyphExtents
 computes the pixel extents on display
@@ -853,6 +861,14 @@ The
 data type is defined by the FreeType library, and the
 .B XGlyphInfo
 data type is defined by the X Rendering Extension library.
+.IP
+If any of the
+.I glyphs
+are missing (determined by a check with
+.BR XftFontCheckGlyph ()),
+the corresponding entry in
+.I extents
+is filled with zeroes.
 .\" *************************************************************************
 .SS "Drawing Strings (and Other Things)"
 .PS