XDrawText(3X11) X Version 11 (Release 6.6) XDrawText(3X11)
NAME
XDrawText, XDrawText16, XTextItem, XTextItem16 - draw
polytext text and text drawing structures
SYNTAX
XDrawText(display, d, gc, x, y, items, nitems)
Display *display;
Drawable d;
GC gc;
int x, y;
XTextItem *items;
int nitems;
XDrawText16(display, d, gc, x, y, items, nitems)
Display *display;
Drawable d;
GC gc;
int x, y;
XTextItem16 *items;
int nitems;
ARGUMENTS
d Specifies the drawable.
display Specifies the connection to the X server.
gc Specifies the GC.
items Specifies an array of text items.
nitems Specifies the number of text items in the array.
x
y Specify the x and y coordinates, which are
relative to the origin of the specified drawable
and define the origin of the first character.
DESCRIPTION
The XDrawText16 function is similar to XDrawText except that
it uses 2-byte or 16-bit characters. Both functions allow
complex spacing and font shifts between counted strings.
Each text item is processed in turn. A font member other
than None in an item causes the font to be stored in the GC
and used for subsequent text. A text element delta specifies
an additional change in the position along the x axis before
the string is drawn. The delta is always added to the
character origin and is not dependent on any characteristics
of the font. Each character image, as defined by the font
in the GC, is treated as an additional mask for a fill
operation on the drawable. The drawable is modified only
where the font character has a bit set to 1. If a text item
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generates a BadFont error, the previous text items may have
been drawn.
For fonts defined with linear indexing rather than 2-byte
matrix indexing, each XChar2b structure is interpreted as a
16-bit number with byte1 as the most significant byte.
Both functions use these GC components: function, plane-
mask, fill-style, font, subwindow-mode, clip-x-origin,
clip-y-origin, and clip-mask. They also use these GC mode-
dependent components: foreground, background, tile, stipple,
tile-stipple-x-origin, and tile-stipple-y-origin.
XDrawText and XDrawText16 can generate BadDrawable, BadFont,
BadGC, and BadMatch errors.
STRUCTURES
The XTextItem and XTextItem16 structures contain:
typedef struct {
char *chars; /* pointer to string */
int nchars; /* number of characters */
int delta; /* delta between strings */
Font font; /* Font to print it in, None don't change */
} XTextItem;
typedef struct {
XChar2b *chars; /* pointer to two-byte characters */
int nchars; /* number of characters */
int delta; /* delta between strings */
Font font; /* font to print it in, None don't change */
} XTextItem16;
If the font member is not None, the font is changed before
printing and also is stored in the GC. If an error was
generated during text drawing, the previous items may have
been drawn. The baseline of the characters are drawn
starting at the x and y coordinates that you pass in the
text drawing functions.
For example, consider the background rectangle drawn by
XDrawImageString. If you want the upper-left corner of the
background rectangle to be at pixel coordinate (x,y), pass
the (x,y + ascent) as the baseline origin coordinates to the
text functions. The ascent is the font ascent, as given in
the XFontStruct structure. If you want the lower-left
corner of the background rectangle to be at pixel coordinate
(x,y), pass the (x,y - descent + 1) as the baseline origin
coordinates to the text functions. The descent is the font
descent, as given in the XFontStruct structure.
DIAGNOSTICS
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BadDrawable
A value for a Drawable argument does not name a
defined Window or Pixmap.
BadFont A value for a Font or GContext argument does not
name a defined Font.
BadGC A value for a GContext argument does not name a
defined GContext.
BadMatch An InputOnly window is used as a Drawable.
SEE ALSO
XDrawImageString(3X11), XDrawString(3X11), XLoadFont(3X11)
Xlib - C Language X Interface
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