CODEWITHSUNDEEP
javaandroidimage-manipulation
Umair A.
Umair A.

Reputation: 6873

What's wrong with this Java code for Android?

I have written this piece of code to break an image into 9 pieces and it gives me runtime error. There is no error in LogCat and I am stuck. The error comes at line 7 line from bottom (Bitmap.createBitmap(...);). 

public Bitmap[] getPieces(Bitmap bmp) {
        Bitmap[] bmps = new Bitmap[9];

        int width = bmp.getWidth();
        int height = bmp.getHeight();

        int rows = 3;
        int cols = 3;

        int cellHeight = height / rows;
        int cellWidth = width / cols;

        int piece = 0;

        for (int x = 0; x <= width; x += cellWidth) {
            for (int y = 0; y <= height; y += cellHeight) {
                Bitmap b = Bitmap.createBitmap(bmp, x, y, cellWidth,
                        cellHeight, null, false);
                bmps[piece] = b;
                piece++;
            }
        }

        return bmps;
    }

Upvotes: 1

Views: 267

Answers (3)

Lou Franco
Lou Franco

Reputation: 89232

In your code, piece can be greater than 8, so you are getting index out of bounds on bmps. You need to rewrite it so that the right-most and bottom-most pieces just have all of the extra and aren't necessarily the same size.

Or, if you need them to be the same size, drop the extra rows/cols. To make sure, I would formulate my for loop like this

   for (int cellX = 0; cellX < 3; cellX++) {
        int x = cellX * cellWidth;
        for (int cellY = 0; cellY < 3; cellY++) {
               int y = cellY * cellHeight;
               // find the cellWidth/Height that doesn't overflow the original image
               Bitmap b = // get the bitmap

               bmps[piece] = b;
               piece++;
        }
   }

Upvotes: 0

ShahidAzim
ShahidAzim

Reputation: 1494

It is a limitation of android framework which doesn't give proper error message. The ideal solution would be to wrap your code in try / catch block and log the exception to console and fix your code accordingly, but use it only for debugging purposes.

try {
    // Code
}
catch (Exception e) {
    Log.e("ERROR", "ERROR IN CODE:"+e.toString());
}

The above code extracted from here:

http://moazzam-khan.com/blog/?p=41

Upvotes: 4

thejh
thejh

Reputation: 45578

Instead of

    for (int x = 0; x <= width; x += cellWidth) {
        for (int y = 0; y <= height; y += cellHeight) {

use

    for (int x = 0; x+cellWidth < width; x += cellWidth) {
        for (int y = 0; y+cellHeight < height; y += cellHeight) {

to avoid fetching parts of the image that (at least partly) don't exist.

Upvotes: 2

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