NAME
XDrawText, XDrawText16, XTextItem, XTextItem16 - draw polytext text and
text drawing structures
SYNTAX
int XDrawText(Display *display, Drawable d, GC gc, int x, int y,
XTextItem *items, int nitems);
int XDrawText16(Display *display, Drawable d, GC gc, int x, int 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 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
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(3), XDrawString(3), XLoadFont(3)
Xlib - C Language X Interface