Creating a User Interface in JavaFX - JavaFX 8: A Definitive Guide to Building Desktop, Mobile, and Embedded Java Clients - page 68

Using the PathTransition Class
As shown in Listing 2-7, defining a PathTransition includes supplying an instance of type Path to the path property
that represents the geometric path that the node is to travel. Here we're creating a Path instance that defines an arc
beginning at 100 pixels on the x axis and 50 pixels on the y axis, ending at 300 pixels on the x axis and 50 pixels on the y
axis, with 350 pixel horizontal and vertical radii. This is accomplished by creating a Path that contains the MoveTo and
ArcTo path elements. Take a look at the javafx.scene.shape package in the JavaFX API docs for more information on
the PathElement class and its subclasses, which are used for creating a path.

■ the properties in the ArcTo class are fairly intuitive except for sweepFlag . if sweepFlag is true, the line joining
the center of the arc to the arc itself sweeps through increasing angles. Otherwise, it sweeps through decreasing angles.

Tip

Another property of the PathTransition class is orientation, which controls whether the node's orientation
remains unchanged or stays perpendicular to the path's tangent as it moves along the path. Listing 2-7 uses the
OrientationType.ORTHOGONAL_TO_TANGENT constant to accomplish the latter, as the former is the default.

Drawing an Ellipse
As shown in Listing 2-7, drawing an Ellipse is similar to drawing a Circle , the difference being that an additional
radius is required ( radiusX and radiusY instead of just radius ).
Now that you've learned how to animate nodes by creating a timeline and by creating transitions, we create a very
simple Pong-style game that requires animating a ping pong ball. In the process, you learn how to detect when the
ball has hit a paddle or wall in the game.

The Zen of Node Collision Detection
When animating a node, you sometimes need to know when the node has collided with another node. To
demonstrate this capability, our colleague Chris Wright developed a simple version of the Pong-style game that we
call ZenPong. Originally we asked him to build the game with only one paddle, which brought the famous Zen koan
(philosophical riddle), “What is the sound of one hand clapping,” to mind. Chris had so much fun developing the
game that he snuck a second paddle in, but we're still calling this example ZenPong. Figure 2-11 shows this very
simple form of the game when first invoked.