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. and define
the origin of the first character
- x
-
- y
- Specify the x and y coordinates, which are relative to the
origin of the specified drawable .
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