Mirroring Pixels

[Monkey101]

Mirroring is done by copying. Suppose a Picture has H rows of Pixels and W columns of Pixels and W is an even number, like W is 2N. Here N is a the whole number that is exactly 1/2 of W. How many Pixels are copied when the Picture is mirrored along the vertical line through its middle? <-- I understand what the question is asking. Its just how would I go about doing it? Should I type up a program?

[NormR1]

What are the coordinates for the pixels (source and target) as they are copied? Make a loop that copies the pixels for each row inside another loop that goes through the rows.

[JamesCherrill]

How many Pixels are copied when the Picture is mirrored along the vertical line through its middle?

Isn't the answer just "all of them" (H*W)? Or am I missing something?

[Monkey101]

public void mirrorVertical()
  {
    int width = this.getWidth();
    int mirrorPoint = width / 2;
    Pixel leftPixel = null;
    Pixel rightPixel = null;

   for(int y = 0; y < getHeight(); y++)
     {
       for(int x =0; x < mirrorPoint; x++)
        {
          leftPixel = getPixel(x,y);
          rightPixel = getPixel(width - 1- x, y);
          rightPixel.setColor(leftPixel.getColor());
       }
    }
  }

  public static void main(String[] args) 
  {
     String fileName = FileChooser.pickAFile();
     Picture pictObj = new Picture(fileName);
     pictObj.mirrorVertical();
     pictObj.repaint();
  }

This is what I have so far. I would have to change my for{} loops and add the source, target variables to count the copied pixels?

[NormR1]

Can you explain the logic for what you want the code to do?
Make a list of the steps in pseudo code.

What happens when you compile and execute the code?

[Monkey101]

I want the code to display the number pixels that are copied when the Picture is mirrored along the vertical line.

In my for loop I added the variable count

int count =0;

for(int y = 0; y < getHeight(); y++)
     {
       for(int x =0; x < mirrorPoint; x++)
        {
          leftPixel = getPixel(x,y);
          rightPixel = getPixel(width - 1- x, y);
          rightPixel.setColor(leftPixel.getColor());

          count = count + 1;
       }
    }

When I run the code its displays 153600 for the number of pixels copied.
I realized the code muiltple (Height x Width) / 2.
So I am assuming my answer is correct for the question...

[NormR1]

Counting the number moved doesn't mean that they were moved to the correct locations.

All the counting does is verify the product of width/2 * height