Drawing text in ProXL is like drawing lines or shapes. This means that
every command to draw text must supply a position at which the text is
to be drawn. ProXL does not maintain a current drawing
position in a window, so you cannot use the standard Prolog
primitives such as write/[1,2]
, or format/[2,3]
1 for putting text into an X window.
Furthermore, note that the position in a drawable at which text is to be drawn is given in pixel coordinates, not character coordinates. There are three reasons for this:
ProXL provides primitives for determining how large a string will be when it is displayed, including a primitive that will determine how many pixels left, right, above, and below the origin point a text string will occupy.