Question

A Color class has a constructor that accepts three integer parameters: red, green and blue components in the range of 0 ... 255 with 0 representing no contribution of the component and 255 being the most intense value for that component. The effect of full or semi-transparency can be achieved by adding another component to the color called an alpha channel. This value can also be defined to be in the range of 0...255 with 0 representing opaque or totally non-transparent, and 255 representing full transparency. Define a class AlphaChannelColor to be a subclass of the Color class. AlphaChannelColor should have the following: - an integer instance variable alpha - a constructor that accepts four parameters: red, green, blue and alpha values in that order. The first three should be passed up to the Color class' constructor, and the alpha value should be used to initialize the alpha instance variable. - a getter (accessor) method for the alpha instance variable

Answer 1

The following are the code in the Java Programming Language.

//define a class and inherit the other class

public class AlphaChannelColor extends Color {

//define constructor and pass arguments

public AlphaChannelColor(int red, int green, int blue, int alpha) {

super(red, green, blue);

this.alpha = alpha;

}

//define function

public int getAlpha()

{

return alpha;

}

//declare a private type variable

private int alpha;

}

Step-by-step explanation:

The following are description of the program.

• Firstly, define a class 'AlphaChannelColor' that inherits the other class that is 'Color' through the extend keyword.
• Define the constructor (in Java, the class name and the name of the constructor remain same) and pass four integer data type arguments 'red', 'green', 'blue' and 'alpha' in its parameter.
• Define the integer data type function 'getAlpha()' that returns the value of the variable 'alpha'.