从中心旋转缩放的图像

Question

I have some sprites (Well, custom classes that implement Sprite , but whatever) that I resize. AndEngine resizes the image from the center, which makes an image placed at 0,0 no longer appear at 0,0. To fix this I applied

    sprite.setScaleCenterX(0);
    sprite.setScaleCenterY(0);

This places the image where I want it. However, now when I rotate the image, the image moves around (If the image were a plain square, rotating it should make no visible change). To fix this I applied

    sprite.setRotationCenterX((sprite.getWidth() * sprite.getScaleX()) / 2);
    sprite.setRotationCenterY((sprite.getHeight() * sprite.getScaleY()) / 2);

(For some reason, resizing a Sprite doesn't change the dimensions of the sprite, just the visual image, hence multiplying it by the scale). This, however, did not correct the problem, but merely changed where the image moved to when flipped.

Is my math off here? Wouldn't this center the rotation on the image so that the image doesn't move position? Or is there something else I'm missing?

Below is full code:

    Sprite sprite = new Sprite(0, 0, singleTrackTR, getVertexBufferObjectManager());
    sprite.setScale(scaleX, scaleY);
    sprite.setScaleCenterX(0);
    sprite.setScaleCenterY(0);
    sprite.setRotationCenterX((sprite.getWidth() * sprite.getScaleX()) / 2);
    sprite.setRotationCenterY((sprite.getHeight() * sprite.getScaleY()) / 2);

Answer 1

All your code is correct. I tried it myself, both the setProperty(x, y) and the setPropertyX/Y(a) versions.

By any chance, do you have it connected to a Body? Note that the Body also doesn't scale with a Sprite's setScale. It has its own setTransform method, which takes x and y (that you both have to divide by PhysicsConstants.PIXEL_TO_METER_RATIO_DEFAULT) and a rotation value.