CODEWITHSUNDEEP
java
Slurp123
Slurp123

Reputation: 3

How to flip an image vertically?

I'm trying to get this code to run, but I keep getting an error saying:

at main.Main.flipVertically(Main.java:403) which is the code below.

img[row][col] = img[height - row - 1][col];

I don't know what's wrong with the code or the error they are talking about.

Here's the rest of the code:

public static int[][] flipVertically(int[][] img) {

    String dir = "image.jpg";

    img = Util.readImageToMatrix(dir);


    int height = img[0].length;
    int width = img.length;

    for(int row = 0; row < height/2; row++)
        {

            for(int col = 0; col < width; col++)
            {
                int p = img[row][col];
                img[row][col] = img[height - row - 1][col];
                img[height - row - 1][col] = p;
            }
        }
    return img;


}

Upvotes: 0

Views: 714

Answers (1)

user8426627
user8426627

Reputation: 943

  1. height and width swapped

    int height = img.length;
int width = img[0].length;

  2. you souldnt read the matrix in the loop and use the parameter img from function input, or better create a new matrix.

  3. you can swap entire rows like:

    public static void flipVertically(int[][] img) {

    int height = img.length;
    int width = img[0].length;  

    for(int row = 0; row < height/2; row++)
    {
        int [] myrow =  img[row];
        img [row] = img[height - row - 1];

        img[height - row - 1] = myrow;          
    }      
}

Upvotes: 1

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