Gdk::Region
class Gdk::Region
Gdk::Region is an opaque data type holding a set of arbitrary pixels, and is usually used for clipping graphical operations (see Gdk::GC#set_clip_region).
Class Methods
Gdk::Region.new

Creates a new empty Gdk::Region.
 Returns : a new empty Gdk::Region.
Gdk::Region.new(rectangle)

Creates a new region containing the area rectangle.
 rectangle: a Gdk::Rectangle
 Returns: a new Gdk::Region
Gdk::Region.new(points, fill_rule)

Creates a new Gdk::Region using the polygon defined by a number of points.
 points: [[x1, y1], [x2, y2], ... ]: an array of points.
 fill_rule: specifies which pixels are included in the region when the polygon overlaps itself. (GdkFillRule)
 Returns: a new Gdk::Region based on the given polygon.
Instance Methods
clipbox

Returns the smallest rectangle which includes the entire Gdk::Region.
 Returns: the smallest rectangle(Gdk::Rectangle) which includes all of region.
rectangles

Obtains the area covered by the region as a list of rectangles.
 Returns: an array of rectangles(Gdk::Rectangle)
empty?

Returns true if the Gdk::Region is empty.
 Returns: true if region is empty.
==(other)

Returns true if the two regions are the same value.
 other: a Gdk::Region.
 Returns: true if self and other are equal.
point_in?(x, y)

Returns true if a point is in a region.
 x: the x coordinate of a point.
 y: the y coordinate of a point.
 Returns: true if the point is in region.
rect_in(rectangle)

Tests whether a rectangle is within a region.
 rect: a Gdk::Rectangle.
 Returns: Gdk::Region::OVERLAP_RECTANGLE_IN, Gdk::Region::OVERLAP_RECTANGLE_OUT, or Gdk::Region::OVERLAP_RECTANGLE_PART, depending on whether the rectangle is inside, outside, or partly inside the Gdk::Region, respectively.
offset(dx, dy)

Moves a region the specified distance.
 dx: the distance to move the region horizontally.
 dy: the distance to move the region vertically.
 Returns: self
shrink(dx, dy)

Resizes a region by the specified amount. Positive values shrink the region. Negative values expand it.
 dx: the number of pixels to shrink the region horizontally.
 dy: the number of pixels to shrink the region vertically.
 Returns: self
union(other)

Sets the area of this region to the union of the areas of self and other. The resulting area is the set of pixels contained in either region or rect.
 other: a Gdk::Region or a Gdk::Rectangle
 Returns: self
intersect(other)

Sets the area of this region to the intersection of the areas of self and other. The resulting area is the set of pixels contained in both self and other.
 other: a Gdk::Region
 Returns: self
subtract(other)

Subtracts the area of other from the area of this region. The resulting area is the set of pixels contained in self but not in other.
 other: a Gdk::Region
 Returns: self
xor(other)

Sets the area of this region to the exclusiveOR of the areas of self and other. The resulting area is the set of pixels contained in one or the other of the two sources but not in both.
 other: a Gdk::Region
 Returns: self
spans_intersect_each(spans, sorted){span ...}

Calls a block on each span in the intersection of region and spans.
 spans: an array of spans [[x1, y1, width1], [x2, y2, width2], ... ].
 sorted: true if spans is sorted wrt. the y coordinate
 {x, y, width ...}: a block to call on each span in the intersection
 Returns: self
Constants
GdkFillRule
The method for determining which pixels are included in a region, when creating a Gdk::Region from a polygon. The fill rule is only relevant for polygons which overlap themselves.
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.
WINDING_RULE
 overlapping areas are always included.
GdkOverlapType
Specifies the possible values returned by Gdk::Region#rect_in.
OVERLAP_RECTANGLE_IN
 if the rectangle is inside the GdkRegion.
OVERLAP_RECTANGLE_OUT
 if the rectangle is outside the GdkRegion.
OVERLAP_RECTANGLE_PART
 the rectangle is partly inside the GdkRegion.
See Also
Gdk::Rectangle, Gdk::Span?
Keyword(s):
References:[apigdkindex] [Cairo::Context] [Ruby/GDK] [indexrubygdk2] [Gdk::EventExpose] [Pango::Layout] [Gdk::GC] [Gdk::Window] [Gdk::Region::OverlapType] [News_20050306_1] [Gdk::Drawable] [News_20031116_1] [Gdk::Region] [Gtk::Widget] [Gdk::Region::FillRule]