|Modifier and Type||Field and Description|
No background singleton to avoid creating several ones.
|Modifier and Type||Method and Description|
Applies the background on a graphics context.
Indicates whether some other object is "equal to" this one.
Returns a hash code value for the object.
Tells whether or not this background is transparent.
public static final NoBackground NO_BACKGROUND
public void apply(GraphicsContext g, int width, int height)
equals method implements an equivalence relation on non-null object references:
trueif and only if
y, multiple invocations of
trueor consistently return
false, provided no information used in
equalscomparisons on the objects is modified.
equals method for class
Object implements the most discriminating possible
equivalence relation on objects; that is, for any non-null reference values
y, this method returns
true if and only if
y refer to the
same object (
x == y has the value
Note that it is generally necessary to override the
hashCode method whenever this method
is overridden, so as to maintain the general contract for the
hashCode method, which
states that equal objects must have equal hash codes.
public int hashCode()
The general contract of
hashCodemethod must consistently return the same integer, provided no information used in
equalscomparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
equals(Object)method, then calling the
hashCodemethod on each of the two objects must produce the same integer result.
Object.equals(java.lang.Object)method, then calling the
hashCodemethod on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.
As much as is reasonably practical, the hashCode method defined by class
return distinct integers for distinct objects. (This is typically implemented by converting the
internal address of the object into an integer, but this implementation technique is not required
by the JavaTM programming language.)
public boolean isTransparent(int width, int height)
A background is considered as transparent if it does not draw every pixel with maximal opacity when it is applied. If a widget has a transparent background, its parent has to be rendered before the widget.