9 Working with
Raster
Selection
135
Comparing the
Crossing Window
selection methods
Let us consider several examples that illustrate the difference between
raster
selection types
that apply to the same
selection methods.
In the first example we select raster using the
Crossing Window
method with the
different raster selection types.
Note that when you select raster with
Crossing Window,
you should click on two
opposite corners of a rectangular area. Once the area is defined, the program
selects all raster data that lies entirely inside the area and adds the raster objects
crossing the area boundary.
In the examples below we select, and then
delete raster to see which raster objects have
been selected.
In all three cases the selection window is
defined in the same manner. The dimension
line and the text lie inside the window, the
extension lines cross the selection window.
The selection window boundary is shown as a
dashed rectangle.
Entity Type Recognition
In this case the program selects the entire
dimensional object including the extension
lines up their intersections with the third circle,
endpoints of the crossed
raster entities
. After
deletion of raster graphics (see the figure) the
raster circles that were crossed by the deleted
extension lines are not broken.
Line Following
In this case the program selects the entire
dimensional object as well, but extension lines
are selected only up to their intersections with
the first circle. Parts of the crossed raster lines
limited by nodes are added to the selection
set. This shows in the figure that represents
the deletion result.