Undo a horizontally/vertically flipped bitmap

Question

I have succesfully flipped a bitmap horizontally

mMirror.preScale(-1.0f, 1.0f);`

and vertically

mFlip.setScale(-1, 1);
mFlip.postTranslate(bitmap.getWidth(), 0);

How do i revert these actions?

Answer 1

EDIT: you can try animations

final ObjectAnimator rotate = ObjectAnimator.ofFloat(imageview,
                "rotationY", 0f, 180f);
        rotate.setDuration(500); /* Duration for flipping the image */
        rotate.setRepeatCount(0);
        rotate.setInterpolator(new AccelerateDecelerateInterpolator());
rotate.start();

in case of undo change rotation values to 180,360

final ObjectAnimator rotate = ObjectAnimator.ofFloat(imagemain,
                "rotationY", 180f, 360f);
        rotate.setDuration(500); /* Duration for flipping the image */
        rotate.setRepeatCount(0);
        rotate.setInterpolator(new AccelerateDecelerateInterpolator());
        rotate.start();

Previous answer: You should again call these methods to undo the changes... or you can take help from this method:

public static final int FLIP_VERTICAL = 1;
    public static final int FLIP_HORIZONTAL = 2;

public Bitmap flipImage(Bitmap src, int type) {
        // create new matrix for transformation
        Matrix matrix = new Matrix();
        // if vertical
        if (type == FLIP_VERTICAL) {
            // y = y * -1
            matrix.preScale(1.0f, -1.0f);
        }
        // if horizonal
        else if (type == FLIP_HORIZONTAL) {
            // x = x * -1
            matrix.preScale(-1.0f, 1.0f);
            // unknown type
        } else {
            return null;
        }

        // return transformed image
        return Bitmap.createBitmap(src, 0, 0, src.getWidth(), src.getHeight(),
                matrix, true);
    }

You can flip your bitmap vertically or horizontally by putting the type in the arguments and restore them to original by again calling that method.