gdk-Points-Rectangles-and-Regions: Points, Rectangles and Regions

In RGtk2: R Bindings for Gtk 2.8.0 and Above

Description

Simple graphical data types

Methods and Functions

gdkRectangleIntersect(src1, src2)
gdkRectangleUnion(src1, src2)
gdkRegionNew()
gdkRegionPolygon(points, fill.rule)
gdkRegionCopy(object)
gdkRegionRectangle(rectangle)
gdkRegionGetClipbox(object)
gdkRegionGetRectangles(object)
gdkRegionEmpty(object)
gdkRegionEqual(object, region2)
gdkRegionRectEqual(object, rectangle)
gdkRegionPointIn(object, x, y)
gdkRegionRectIn(object, rect)
gdkRegionOffset(object, dx, dy)
gdkRegionShrink(object, dx, dy)
gdkRegionUnionWithRect(object, rect)
gdkRegionIntersect(object, source2)
gdkRegionUnion(object, source2)
gdkRegionSubtract(object, source2)
gdkRegionXor(object, source2)
gdkRegionSpansIntersectForeach(object, spans, sorted, fun, data)

Detailed Description

GDK provides the GdkPoint, GdkRectangle, GdkRegion and GdkSpan data types for representing pixels and sets of pixels on the screen. GdkPoint is a simple structure containing an x and y coordinate of a point. GdkRectangle is a structure holding the position and size of a rectangle. The intersection of two rectangles can be computed with gdkRectangleIntersect. To find the union of two rectangles use gdkRectangleUnion. GdkRegion is an opaque data type holding a set of arbitrary pixels, and is usually used for clipping graphical operations (see gdkGCSetClipRegion). GdkSpan is a structure holding a spanline. A spanline is a horizontal line that is one pixel wide. It is mainly used when rasterizing other graphics primitives. It can be intersected to regions by using gdkRegionSpansIntersectForeach.

Structures

GdkPoint

Defines the x and y coordinates of a point. GdkPoint is a transparent-type.

x

the x coordinate of the point.

y

the y coordinate of the point.

GdkRectangle

Defines the position and size of a rectangle. GdkRectangle is a transparent-type.

x

[integer] the x coordinate of the left edge of the rectangle.

y

[integer] the y coordinate of the top of the rectangle.

width

[integer] the width of the rectangle.

height

[integer] the height of the rectangle.

GdkRegion

A GdkRegion represents a set of pixels on the screen.

GdkSpan

A GdkSpan represents a horizontal line of pixels starting at the pixel with coordinates x, y and ending before x + width, y. GdkSpan is a transparent-type.

x

[integer] x coordinate of the first pixel.

y

[integer] y coordinate of the first pixel.

width

[integer] number of pixels in the span.

Enums and Flags

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.

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 gdkRegionRectIn.

in

if the rectangle is inside the GdkRegion.

out

if the rectangle is outside the GdkRegion.

part

if the rectangle is partly inside the GdkRegion.

User Functions

GdkSpanFunc(span, data)

This defines the type of the function passed to gdkRegionSpansIntersectForeach.

span

a GdkSpan.

data

the user data passed to gdkRegionSpansIntersectForeach.

Author(s)

Derived by RGtkGen from GTK+ documentation

References

https://developer.gnome.org/gdk2/stable/gdk2-Points-Rectangles-and-Regions.html

RGtk2 documentation built on Oct. 14, 2021, 5:08 p.m.