Manpages - XDrawString.3

XDrawString, XDrawString16 - draw text characters

int XDrawString ( Display */display/ , Drawable d , GC gc , int x , int y , _Xconst char */string/ , int length );

int XDrawString16 ( Display */display/ , Drawable d , GC gc , int x , int y , _Xconst XChar2b */string/ , int length );

1. Specifies the drawable.
2. Specifies the connection to the X server.
3. Specifies the GC.
4. Specifies the number of characters in the string argument.
5. Specifies the character string.
6. 
   
7. Specify the x and y coordinates, which are relative to the origin of the specified drawable and define the origin of the first character.

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. For fonts defined with 2-byte matrix indexing and used with XDrawString16, each byte is used as a byte2 with a byte1 of zero.

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.

XDrawString and XDrawString16 can generate BadDrawable, BadGC, and BadMatch errors.

BadDrawable

A value for a Drawable argument does not name a defined Window or Pixmap.

BadGC

A value for a GContext argument does not name a defined GContext.

BadMatch

An InputOnly window is used as a Drawable.

BadMatch

Some argument or pair of arguments has the correct type and range but fails to match in some other way required by the request.

XDrawImageString(3), XDrawText(3), XLoadFont(3)
Xlib - C Language X Interface