Drawing mirrored bitmaps in android

Question

I\'m trying to learn how to make an animated sprite in android and couldn\'t figure out how to go about organising my bitmaps. I have a sprite sheet of my character walking

Answer 1

To draw a vertical mirrored bitmap bmp on a canvas:

Matrix m = new Matrix();
// Mirror is basically a rotation
m.setScale( -1 , 1 );
// so you got to move your bitmap back to it's place. otherwise you will not see it
m.postTranslate(canvas.getWidth(), 0);
canvas.drawBitmap(bmp, m, p);

Answer 2

Method 2 would be way too expensive, and you don't need a canvas to flip a bitmap. Simply create another bitmap with a Matrix applied, like so:

BitmapDrawable flip(BitmapDrawable d)
{
    Matrix m = new Matrix();
    m.preScale(-1, 1);
    Bitmap src = d.getBitmap();
    Bitmap dst = Bitmap.createBitmap(src, 0, 0, src.getWidth(), src.getHeight(), m, false);
    dst.setDensity(DisplayMetrics.DENSITY_DEFAULT);
    return new BitmapDrawable(dst);
}

Answer 3

To mirror your sprite simply apply the following transform on the Canvas: scale(-1, 1). You will have to offset the sprite by its width too.