[JAVA][Beginning Java 8 Games Development]

Chapter 6 ■ The Foundation of Game Design: The JavaFX Scene Graph and the InvinciBagel Game Infrastructure
The Java class extension hierarchy for the Pos class starts at the java.lang.Object masterclass and progresses to the
java.lang.Enum class, finally ending with the javafx.geometry.Pos class. As Figure 6-4 demonstrates (l. 6), Pos
is in the JavaFX geometry package and uses the following subclass hierarchy structure:
java.lang.Object
> java.lang.Enum
> javafx.geometry.Pos
The Pos class has a set of constants for providing a generalized horizontal and vertical positioning and alignment
(see Table 6-1). As you will see in the next section, you will have to use an Insets class and object to obtain the
pixel-accurate positioning that you desire. You will employ the BOTTOM_LEFT constant to position the Button
control bank in the bottom-left corner of the splash screen.
Table 6-1. Pos Class Enum Constants That Can Be Used for Positioning and Alignment in JavaFX
Pos Constant
BASELINE_CENTER
BASELINE_LEFT
BASELINE_RIGHT
BOTTOM_CENTER
BOTTOM_LEFT
BOTTOM_RIGHT
CENTER
CENTER_LEFT
CENTER_RIGHT
TOP_CENTER
TOP_LEFT
TOP_RIGHT
Positioning Result (Object)
On the baseline, vertically; at the center, horizontally
On the baseline, vertically; on the left, horizontally
On the baseline, vertically; on the right, horizontally
On the bottom, vertically; at the center, horizontally
On the bottom, vertically; on the left, horizontally
On the bottom, vertically; on the right, horizontally
At the center, vertically and horizontally
At the center, vertically; on the left, horizontally
At the center, vertically; on the right, horizontally
At the top, vertically; at the center, horizontally
At the top, vertically; on the left, horizontally
At the top, vertically; on the right, horizontally
Because the Pos class offers generalized positioning, it should be used in conjunction with the Insets class to
effect pixel-precise positioning. Let’s take a look at the Insets class next, as it is also in the javafx.geometry package.
The JavaFX Insets Class: Providing Padding Values for Your UI
The Insets class is a public class that directly extends the java.lang.Object masterclass, meaning that the Insets class
was coded from scratch to provide insets, or offsets inside a rectangular area. Imagine a picture frame in which you
place a mat, or an attractive border between the frame on the outside and the picture on the inside. This is what
the Insets class does with two constructor methods: one provides equal, or even, insets, and the other, unequal, or
uneven, insets.
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