By using this code we can rotate an image:
JavaScript
x
public static Bitmap RotateBitmap(Bitmap source, float angle) {
Matrix matrix = new Matrix();
matrix.postRotate(angle);
return Bitmap.createBitmap(source, 0, 0, source.getWidth(), source.getHeight(), matrix, true);
}
But how can we flip an image horizontally or vertically?
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Answer
Given cx,cy
is the centre of the image:
Flip in x:
JavaScript
matrix.postScale(-1, 1, cx, cy);
Flip in y:
JavaScript
matrix.postScale(1, -1, cx, cy);
Altogether:
JavaScript
public static Bitmap createFlippedBitmap(Bitmap source, boolean xFlip, boolean yFlip) {
Matrix matrix = new Matrix();
matrix.postScale(xFlip ? -1 : 1, yFlip ? -1 : 1, source.getWidth() / 2f, source.getHeight() / 2f);
return Bitmap.createBitmap(source, 0, 0, source.getWidth(), source.getHeight(), matrix, true);
}