Please help me with the questions below and explain the lines of code.

Method 1: negative

Add a method (negative) to Picture.java that takes in two parameters (1 pt), the first and last index which represent the region (part) of the pixel array to be modified.

o The method should access the pixel array of the calling picture object (that is use the this.getPixels() line to store the picture's pixels in an array).

o Then, using a while loop, invert the color (create the negative) of each pixel from the starting index to the ending index (inclusive) (1 pt).

o The method header for this should be something like: public void negative(int start, int end)

Method 2: grayscale

Add another method (named grayscale) to Picture.java. Like the negative method, grayscale should take both a starting and ending index to determine which pixels will be modified (1 pt). For the pixels in the specified range, you need to change the colors to their appropriate grayscale color using another while loop (1 pt).

The method header should look like: public void grayscale(int start, int end)

Method 3: myFilter

Add another method (named myFilter) to Picture.java. Again, this method should take at least two parameters: the first and last index in the pixel array to be modified (1 pt). You may have more parameters, depending on the effect you are using.

Apply any effect of your choice to the pixels in range using a while loop (1 pt). You can use any effect you want other than negative, grayscale, or something shown in the textbook. Take this as a chance to be creative and come up with an interesting effect.

Testing negative, grayscale, and myFilter:

Download the PSA3B.java file and save it in your PSA3/bookClasses directory.

This file will load a Picture of your choice using FileChooser.pickAFile().

Again, you can either choose a file in mediaSources or a personal image.

Display the original image.

Then call the negative method on the top third of pixels in the image. Next call

the grayscale method on the middle third of pixels in the image. Then apply the myFilter method to the bottom third of the pixels in the image (2 pts).

o Hint: Dont hard-code the parameter values for start and end when you call the methods let Java do the calculations for you!

Lastly, display your new image (1 pt).