This procedure returns whether there is a selection. If there isone, the upper left and lower right-hand corners of its bounding boxare returned. These coordinates are specified relative to thedrawable's origin, and bounded by the drawable's extents. Pleasenote that the pixel specified by the lower right-hand coordinate ofthe bounding box is not part of the selection. The selection ends atthe upper left corner of this pixel. This means the width of theselection can be calculated as (x2 - x1), its height as (y2 - y1).Note that the returned boolean does NOT correspond with the returnedregion being empty or not, it always returns whether the selectionis non_empty. See gimp_drawable_mask_intersect() for a booleanreturn value which is more useful in most cases.