GDK Reference Manual

gdk_region_polygon ()
GdkRegion*gdk_region_polygon(GdkPoint *points,
gint npoints,GdkFillRule fill_rule); 

　　Creates a new GdkRegion using the polygon defined by a number of points.

　　points : an array of GdkPoint structs.

　　npoints : the number of elements in the points array.

　　fill_rule : specifies which pixels are included in the region when the polygon overlaps itself.

　　Returns : a new GdkRegion based on the given polygon.

　　enum GdkFillRule

typedef enum
{
GDK_EVEN_ODD_RULE,
GDK_WINDING_RULE
} GdkFillRule; 

　　The method for determining which pixels are included in a region, when creating a GdkRegion from a polygon. The fill rule is only relevant for polygons which overlap themselves.

　　GDK_EVEN_ODD_RULE areas which are overlapped an odd number of times are included in the region, while areas overlapped an even number of times are not.

　　GDK_WINDING_RULE overlapping areas are always included.

gdk_region_destroy ()
voidgdk_region_destroy(GdkRegion *region); 

　　Destroys a GdkRegion.

　　region : a GdkRegion.

gdk_regions_intersect ()
GdkRegion*gdk_regions_intersect (GdkRegion *source1,GdkRegion *source2); 

　　Returns the intersection of two regions.

　　source1 : a GdkRegion.

　　source2 : a GdkRegion.

　　Returns : the intersection of source1 and source2.

gdk_regions_union ()
GdkRegion*gdk_regions_union (GdkRegion *source1,GdkRegion *source2); 

　　Returns the union of two regions. This is all pixels in either of source1 or source2.

　　source1 : a GdkRegion.

　　source2 : a GdkRegion.

　　Returns : the union of source1 and source2.

gdk_regions_subtract ()
GdkRegion*gdk_regions_subtract(GdkRegion *source1,GdkRegion *source2); 

　　Subtracts one region from another. The result is a region containing all the pixels which are in source1, but which are not in source2.

　　source1 : a GdkRegion.

　　source2 : a GdkRegion to subtract from source1.

　　Returns : source1 - source2.

gdk_regions_xor ()
GdkRegion*gdk_regions_xor (GdkRegion *source1,GdkRegion *source2); 

　　Returns the difference between the union and the intersection of two regions. This is a region containing the pixels that are in one of the source regions, but which are not in both.

　　source1 : a GdkRegion.

　　source2 : a GdkRegion.

　　Returns : the difference between the union and the intersection of source1 and source2.

gdk_region_union_with_rect ()
GdkRegion*gdk_region_union_with_rect(GdkRegion *region,GdkRectangle *rect); 

　　Returns the union of a region and a rectangle.

　　region : a GdkRegion.

　　rect : a GdkRectangle.

　　Returns : the union of region and rect.

gdk_region_offset ()
voidgdk_region_offset (GdkRegion *region,gint dx,gint dy); 

　　Moves a region the specified distance.

　　region : a GdkRegion.

　　dx : the distance to move the region horizontally.

　　dy : the distance to move the region vertically.

gdk_region_shrink ()
voidgdk_region_shrink (GdkRegion *region,gint dx,gint dy); 

　　Resizes a region by the specified amount. Positive values shrink the region. Negative values expand it.

　　region : a GdkRegion.

　　dx : the number of pixels to shrink the region horizontally.

　　dy : the number of pixels to shrink the region vertically.

gdk_region_empty ()
gbooleangdk_region_empty(GdkRegion *region);