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<!-- ##### SECTION Title ##### -->
Points, Rectangles and Regions
<!-- ##### SECTION Short_Description ##### -->
simple graphical data types.
<!-- ##### SECTION Long_Description ##### -->
<para>
GDK provides the #GdkPoint, #GdkRectangle and #GdkRegion data types for
representing pixels and sets of pixels on the screen.
</para>
<para>
#GdkPoint is a simple structure containing an x and y coordinate of a point.
</para>
<para>
#GdkRectangle is a structure holding the position and size of a rectangle.
The intersection of two rectangles can be computed with
gdk_rectangle_intersect(). To find the union of two rectangles use
gdk_rectangle_union().
</para>
<para>
#GdkRegion 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()).
</para>
<!-- ##### SECTION See_Also ##### -->
<para>
</para>
<!-- ##### STRUCT GdkPoint ##### -->
<para>
Defines the x and y coordinates of a point.
Note that both are defined as #gint16 values, so the coordinates are limited
to between -32,768 and 32,767.
</para>
@x: the x coordinate of the point.
@y: the y coordinate of the point.
<!-- ##### STRUCT GdkRectangle ##### -->
<para>
Defines the position and size of a rectangle.
</para>
@x: the x coordinate of the left edge of the rectangle.
@y: the y coordinate of the top of the rectangle.
@width: the width of the rectangle.
@height: the height of the rectangle.
<!-- ##### FUNCTION gdk_rectangle_intersect ##### -->
<para>
Calculates the intersection of two rectangles.
</para>
@src1: a #GdkRectangle.
@src2: a #GdkRectangle.
@dest: the intersection of @src1 and @src2.
@Returns: TRUE if the rectangles intersect.
<!-- ##### FUNCTION gdk_rectangle_union ##### -->
<para>
Calculates the union of two rectangles.
The union of rectangles @src1 and @src2 is the smallest rectangle which
includes both @src1 and @src2 within it.
</para>
@src1: a #GdkRectangle.
@src2: a #GdkRectangle.
@dest: the union of @src1 and @src2.
<!-- ##### STRUCT GdkRegion ##### -->
<para>
A GdkRegion represents a set of pixels on the screen.
The only user-visible field of the structure is the user_data member, which
can be used to attach arbitrary data to the #GdkRegion.
</para>
@user_data: arbitrary data attached to the #GdkRegion.
<!-- ##### FUNCTION gdk_region_new ##### -->
<para>
Creates a new empty #GdkRegion.
</para>
@Returns: a new empty #GdkRegion.
<!-- ##### FUNCTION gdk_region_destroy ##### -->
<para>
Destroys a #GdkRegion.
</para>
@region: a #GdkRegion.
<!-- ##### FUNCTION gdk_region_get_clipbox ##### -->
<para>
Returns the smallest rectangle which includes the entire #GdkRegion.
</para>
@region: a #GdkRegion.
@rectangle: returns the smallest rectangle which includes all of @region.
<!-- ##### FUNCTION gdk_region_empty ##### -->
<para>
Returns TRUE if the #GdkRegion is empty.
</para>
@region: a #GdkRegion.
@Returns: TRUE if @region is empty.
<!-- ##### FUNCTION gdk_region_equal ##### -->
<para>
Returns TRUE if the two regions are the same.
</para>
@region1: a #GdkRegion.
@region2: a #GdkRegion.
@Returns: TRUE if @region1 and @region2 are equal.
<!-- ##### FUNCTION gdk_region_point_in ##### -->
<para>
Returns TRUE if a point is in a region.
</para>
@region: a #GdkRegion.
@x: the x coordinate of a point.
@y: the y coordinate of a point.
@Returns: TRUE if the point is in @region.
<!-- ##### FUNCTION gdk_region_rect_in ##### -->
<para>
Tests whether a rectangle is within a region.
</para>
@region: a #GdkRegion.
@rect: a #GdkRectangle.
@Returns: GDK_OVERLAP_RECTANGLE_IN, GDK_OVERLAP_RECTANGLE_OUT, or
GDK_OVERLAP_RECTANGLE_PART, depending on whether the rectangle is inside,
outside, or partly inside the #GdkRegion, respectively.
<!-- ##### ENUM GdkOverlapType ##### -->
<para>
Specifies the possible values returned by gdk_region_rect_in().
</para>
@GDK_OVERLAP_RECTANGLE_IN: if the rectangle is inside the #GdkRegion.
@GDK_OVERLAP_RECTANGLE_OUT: if the rectangle is outside the #GdkRegion.
@GDK_OVERLAP_RECTANGLE_PART: if the rectangle is partly inside the #GdkRegion.
<!-- ##### FUNCTION gdk_region_polygon ##### -->
<para>
Creates a new #GdkRegion using the polygon defined by a number of points.
</para>
@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.
<!-- ##### FUNCTION gdk_region_offset ##### -->
<para>
Moves a region.
</para>
@region: a #GdkRegion.
@dx: the distance to move the region horizontally.
@dy: the distance to move the region vertically.
<!-- ##### FUNCTION gdk_region_shrink ##### -->
<para>
Resizes a region.
</para>
@region: a #GdkRegion.
@dx:
@dy:
<!-- ##### FUNCTION gdk_region_union_with_rect ##### -->
<para>
Returns the union of a region and a rectangle.
</para>
@region: a #GdkRegion.
@rect: a #GdkRectangle.
@Returns: the union of @region and @rect.
<!-- ##### FUNCTION gdk_regions_intersect ##### -->
<para>
Returns the intersection of two regions.
</para>
@source1: a #GdkRegion.
@source2: a #GdkRegion.
@Returns: the intersection of @source1 and @source2.
<!-- ##### FUNCTION gdk_regions_union ##### -->
<para>
Returns the union of two regions.
This is all pixels in either of @source1 or @source2.
</para>
@source1: a #GdkRegion.
@source2: a #GdkRegion.
@Returns: the union of @source1 and @source2.
<!-- ##### FUNCTION gdk_regions_subtract ##### -->
<para>
Subtracts one region from another.
The result is a region containing all the pixels which are in @source1, but
which are not in @source2.
</para>
@source1: a #GdkRegion.
@source2: a #GdkRegion to subtract from @source1.
@Returns: @source1 - @source2.
<!-- ##### FUNCTION gdk_regions_xor ##### -->
<para>
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.
</para>
@source1: a #GdkRegion.
@source2: a #GdkRegion.
@Returns: the difference between the union and the intersection of @source1
and @source2.
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