Color Scaling in Java

Question

I am trying to scale the color components of a pixel. To do this I am creating a new pixel where each color component is the original value * the scaling factor for that color. The resulting pixel must have values that fall within the range of 0 <= color <= 255 .

This is what I am doing so far

public class ColorScale implements Transformer {
    /* This part creates a transformer that scales the color in each pixel by the following factors
        parameter r0 = red factor
        parameter b0 = blue factor
        parameter g0 = green factor 
    */

    public ColorScale(double r0, double g0, double b0) {
       // need guidance as what to do here
    }

    public Pixel transformPixel(pixel p) {
        return p;
    }
}

More info is here: http://www.seas.upenn.edu/~cis120/current/hw/hw07/javadoc/ColorScale.html

I am new to Java, so I just need guidance as to what to do in the ColorScale function.

Answer 1

From the JavaDoc you provided, ColorScale is one of the Transformer implementations.

From your code snippet:

public ColorScale(double r0, double g0, double b0) {
   // need guidance as what to do here
}

This is the constructor. You are creating an instance of a specific implementation of a Pixel Transformer (in this case, ColorScale ).

The constructor should simply set the internal state of the Transformer , and then it will be set up for transforming Pixels via the contract method transformPixel .

In other words,

public ColorScale(double r0, double g0, double b0) {
   // Set internal state fields. 
   this.r0 = r0;
   this.g0 = g0;
   this.b0 = b0;
}