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Thread: ArrayIndexOutOfBounds Help

  1. #1
    Junior Member
    Join Date
    Jan 2013
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    Default ArrayIndexOutOfBounds Help

    Can anyone help me and let me know why this is going out of bounds? Its throwing the exception on line 41
    The program is suppose to take a GImage and rotate it 90 degrees.
     * Mat2670 Homework 4 EX 5
     * Connor Moore
     * 03/07/2013
     * File: fliphorizontal.java
     * This program takes a .gif or .jpg image flips the image
     * horizontally and displays the image after the flip.
    package mat2670;
    import acm.graphics.*;
    import acm.program.*;
    import javax.swing.*;
    public class RotateLeft extends GraphicsProgram {
        public static void main(String[] args) {
            (new RotateLeft()).start();
        public void run() {
            //Declares an image to use
            JFileChooser chooser = new JFileChooser();
            String firefox = "firefox.gif";
            GImage image = new GImage(firefox);
            //Flips the image then shows it to the user.
    //Function that takes a Gimage and flips it horizontally
        private GImage rotateLeft(GImage image) {
            int[][] array = image.getPixelArray();
            int height = array.length;
            int width = array[0].length;
            for (int row = 0; row < width; row++) {
                for (int col = 0; col < height; col++) {
                    int temp = array[col][row];
                    array[row][col] = temp;            
            return new GImage(array);

  2. #2
    Join Date
    Jun 2012
    Left Coast, USA
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    Thanked 97 Times in 88 Posts

    Default Re: ArrayIndexOutOfBounds Help

    Step back from the program a minute and think about what you are trying to do.

    If the number of columns is not equal to the number of rows, you must create a new array.

    For example, suppose the original has 600 rows and 800 columns, Then the rotated image will have 800 rows and 600 columns. You can not simply exchange values the elements of the rows and columns of the original array. Period.

    Now go back to your program and see why it absolutely must create an array out-of-bounds exception for a non-square image. Every single time.


    Create a new array such that the height of the new array is equal to the width of the original and the width of the new array is equal to the height of the original.

    Then copy.



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