Tribblix: manual page: XDrawText.3

XDrawText(3) XLIB FUNCTIONS XDrawText(3)

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