Ubuntu Manpage: XDrawText, XDrawText16, XTextItem, XTextItem16 - draw polytext text and text drawing structures

Provided by: libx11-doc_1.8.7-1build1_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