XPolygonRegion()XPolygonRegion()NameXPolygonRegion – generate a region from points in a polygon.
Synopsis
Region XPolygonRegion(points, n, fill_rule)
XPoint points[];
int n;
int fill_rule;
Arguments
points Specifies a pointer to an array of points.
n Specifies the number of points in the polygon.
fill_rule Specifies whether areas overlapping an odd number of times
should be part of the region (WindingRule) or not part of the
region (EvenOddRule). See Volume One, Chapter 5, The Graph‐
ics Context, for a description of the fill rule.
Returns
The created region.
DescriptionXPolygonRegion() creates a region defined by connecting the specified
points, and returns a pointer to be used to refer to the region.
Regions are located relative to a point (the region origin) which is
common to all regions. In XPolygonRegion(), the coordinates specified
in points are relative to the region origin. By specifying all points
relative to the drawable in which they will be used, the region origin
can be coincident with the drawable origin. It is up to the applica‐
tion whether to interpret the location of the region relative to a
drawable or not.
If the region is to be used as a clip_mask by calling XSetRegion(), the
upper-left corner of the region relative to the drawable used in the
graphics request will be at (xoffset + clip_x_origin, yoffset +
clip_y_origin), where xoffset and yoffset are the offset of the region
(if any) and clip_x_origin and clip_y_origin are elements of the GC
used in the graphics request. The fill_rule can be either of these
values:
EvenOddRule Areas overlapping an odd number of times are not part of
the region.
WindingRule Overlapping areas are always filled.
For more information on structures, see Volume One, Chapter 6, Drawing
Graphics and Text.
Structures
Region is a pointer to an opaque structure type.
See AlsoXClipBox(), XCreateRegion(), XDestroyRegion(), XEmptyRegion(), XEqual‐
Region(), XIntersectRegion(), XOffsetRegion(), XPointInRegion(), XRect‐
InRegion(), XSetRegion(), XShrinkRegion(), XSubtractRegion(), XUnion‐
RectWithRegion(), XUnionRegion(), XXorRegion().
Xlib - Regions XPolygonRegion()