void GPCClipRectangle (llx, lly, urx, ury, units, border) LPLT.C Level 3
 
float llx, lly The lower left corner of the clip rectangle in the units specified.
float urx, ury The upper right corner of the clip rectangle in the units specified.
int units The units of the rectangle definition. The allowable values are
INCH_UNITS, USER_UNITS, or PIXEL_UNITS.
int border = 0 if no border is to be drawn around the rectangle.
= 1 if the rectangle is to have a border.
 
GPCClipRectangle () allows you to draw in a rectangular region and then protect it from any further drawing. Once this call is made the defined rectangle will be clipped against so that additional drawing will be excluded from the region. This call should be made only after the drawing in the protected area is complete.

One use of this function is to insert a label region within a plot area and to have any curves clipped when they cross this region.