The Line source can be used
to interactively or manually add a line to the 3D scene. The two end points
of the line, the resolution of the line, and the visibility of the interaction
widget can be changed used the property sheet. In addition, the two end
points can be specified using the interaction widget. The line can be
translated,
rotated, and scaled using the Actor control area of the Display tab for
this source, and it can be interactively positioned using the Move operation
of the camera. The
object created by this source is a vtkLineSource
object, and the output of this source is vtkPolyData.
An example of a line source is given on the right. Note that in this example
the interaction widget is visible, and the lower left point of the line
is being manipulated. Widget interaction is defined below.
The Line source has only one parameter:
Resolution:
This value represents the number of line segments in line. By default
this value is 1. As opposed to some other sources such as the sphere,
cone, and cylinder, increasing the resolution does not increase the accuracy
of the line, it simple increases the number of colinear line segments
defining the line. This can sometimes be useful when using the data as
input to a filter.
The Line source interaction widget has
the following parameters which are displayed on the Line source property
sheet:
Point1:
These three values indicate the coordinates of one of the two end points
of the line.
Point2:
These three values indicate the other end point coordinate of the line.
Visibility:
This check box can be used to toggle the visibility of the interaction
widget. When the interaction widget is visible, you will see a thick line
with two spheres at the end points. To see the actual line you must turn
off the visibility of the interaction widget. By default the interaction
widget is visible. This check box is tied to the interaction widget and
not the source object, and therefore has an immediate effect (the Accept
button does not need to be pressed).
The Line source interaction widget has
the behavior described below. Changes made through the interaction widget
must be accepted by pressing the Accept button on the property sheet before
the change will be reflected in the output of the line source.
Left
Mouse on End Point Ball: Clicking the left mouse button while the
cursor is over one of the end point spheres, then dragging the mouse will
cause that end point to translate.
Left
Mouse on Line: Clicking the left mouse button while the cursor
is over the line, then dragging the mouse will cause the line to translate.
Right
Mouse on Line: Clicking the left mouse button while the cursor
is over the line, then dragging the mouse will cause the line to increase
or decrease in length. Upward mouse motion will cause an increase in length,
downward motion will cause a decrease in length.
The Line source can be used
to interactively or manually add a line to the 3D scene. The two end points
of the line, the resolution of the line, and the visibility of the interaction
widget can be changed used the property sheet. In addition, the two end
points can be specified using the interaction widget. The line can be
translated,
rotated, and scaled using the Actor control area of the Display tab for
this source, and it can be interactively positioned using the Move operation
of the camera. The
object created by this source is a vtkLineSource
object, and the output of this source is vtkPolyData.
An example of a line source is given on the right. Note that in this example
the interaction widget is visible, and the lower left point of the line
is being manipulated. Widget interaction is defined below.