Ubuntu Manpage: XDrawText, XDrawText16, XTextItem, XTextItem16

Provided by: libx11-doc_1.6.9-2ubuntu1.6_all

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