protected boolean getChildStaticTransformation(View child, Transformation trans)  
    { //图像的中心点和宽度 
        final int childCenter = getCenterOfView(child); 
        final int childWidth = child.getWidth(); 
        int rotationAngle = 0; 
 
        trans.clear(); 
        trans.setTransformationType(Transformation.TYPE_BOTH);        // alpha 和 matrix 都变换 
 
        if (childCenter == mCoveflowCenter)  
        {      // 正中间的childView 
            transformImageBitmap((ImageView) child, trans, 0);     
        }  
        else  
        {          // 两侧的childView 
            rotationAngle = (int) ( ( (float) (mCoveflowCenter - childCenter) / childWidth ) * mMaxRotationAngle ); 
            if (Math.abs(rotationAngle) > mMaxRotationAngle)  
            { 
                rotationAngle = (rotationAngle < 0) ? -mMaxRotationAngle : mMaxRotationAngle; 
            }　//根据偏移角度对图片进行处理，看上去有3D的效果。 
            transformImageBitmap((ImageView) child, trans, rotationAngle); 
        } 
 
        return true; 
    }