在Android上围绕中心旋转位图

Question

Good day, my first question here after wasting 3+ hours. I have reviewed dozens of different posts with similar questions and a small wide of answers.

I'm currently designing a function that takes a bitmap and an angle, and returns a rotated version, for my spaceship android game

public static Bitmap RotateBitmap(Bitmap source, float angle){ 


    Matrix matrix = new Matrix();

    matrix.setRotate(angle, source.getWidth()/2,  source.getHeight()/2);

    return Bitmap.createBitmap(source, 0, 0, source.getWidth(), source.getHeight(), matrix, true);

}

i have tried several different options , mixing translate, post and pre rotate methods, but all proven unneffective. I have to admit I have limited knowledge on matrix but android developer sources seem crystal clear to me, yet any method I tried does anything regarding the pivot point. The rotation always happens but effectively displacing my ship to other hexes

Thanks in advance ^^

Answer 1

Couldn't manage with this function so I ended up making another with same effect.

public void rotate(Bitmap paramBitmap, float angle, Canvas canvas, int x, int y)
{
    canvas.save();
    canvas.translate(x, y);
    canvas.rotate(angle);
    canvas.translate(-paramBitmap.getWidth() / 2, -paramBitmap.getHeight() / 2);
    canvas.drawBitmap(paramBitmap, 0, 0, new Paint());
    canvas.restore();

}

It rotates the canvas instead

Answer 2

I've arrived at the same point you were at when you posted this question. My bitmap is rotated, but also offset. The offset isn't very noticeable until you place another image under or over it, and it then becomes VERY evident.
To clarify, was your workaround to rotate the entire display around your spaceship image, keeping your bitmap image static (ie always pointing in the same direction)? I'm considering moving to a different tool other than Canvas to do this, and will report back if I find something more effective.