Rotate an image in Canvas

We have an Bitmap icon in Canvas.

Bitmap icon = BitmapFactory.decodeResource(getResources(), R.drawable.abc);

We want to rotate it around it’s centre, use this code.

Matrix ma = new Matrix();

    float angle = (float) (System.currentTimeMillis() % 1000) / 1000 * 360;

ma.reset();

ma.postTranslate(-icon.getWidth() / 2, -icon.getHeight() / 2);

ma.postRotate(angle);

ma.postTranslate(200, 200);                       

canvas.drawBitmap(icon, ma, null);

Note the invalidate() must be call.

The line postTranslate(200, 200); show the position of icon.

If we want it rotate around a radius, use this.

ma.postTranslate(-icon.getWidth()/2, 100);

The radius is 100dp.