XDrawText(3X11) XLIB FUNCTIONS 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 rela-
tive 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 generates a BadFont error, the previous
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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
BadDrawable
A value for a Drawable argument does not name a
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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 ALSOXDrawImageString(3X11), XDrawString(3X11), XLoadFont(3X11)
Xlib - C Language X Interface
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