在边界内旋转图像

我尝试在超视图中旋转图像视图,以便在旋转时此图像视图始终接触超视图的边界,而不会与它们交叉,并进行适当的调整。我如何实现这一点?图像视图应能旋转360度。

这里我使用基于三角形公式的计算,考虑到初始图像视图的对角线。

也许我应该考虑图像视图旋转后的新边框(它的X和Y坐标为负,转换后的边框尺寸也变大)。

到目前为止还没有成功,我的图像视图被缩小得太快太多。所以我的目标是,根据我的理解,为 CGAffineTransformScale . 也许还有其他方法可以做到这一点。

// set initial values

    _planImageView.layer.affineTransform = CGAffineTransformScale(CGAffineTransformIdentity, 1, 1);

    _degrees = 0;

    _initialWidth = _planImageView.frame.size.width;
    _initialHeight = _planImageView.frame.size.height;
    _initialAngle = MathUtils::radiansToDegrees(atan((_initialWidth / 2) / (_initialHeight / 2)));

// rotation routine

- (void)rotatePlanWithDegrees:(double)degrees
{
    double deltaDegrees = degrees - _degrees;
    _initialAngle -= deltaDegrees;
    double newAngle = _initialAngle;
    double newWidth = (_initialWidth / 2) * tan(MathUtils::degreesToRadians(newAngle)) * 2;
    double newHeight = newWidth * (_initialHeight / _initialWidth);

    NSLog(@"DEG %f DELTA %f A %f W %f H %f", degrees, deltaDegrees, newAngle, newWidth, newHeight);

    double currentScale = newWidth / _initialWidth;

    _planImageView.layer.affineTransform = CGAffineTransformScale(CGAffineTransformIdentity, currentScale, currentScale);
    _planImageView.layer.affineTransform = CGAffineTransformRotate(_planImageView.layer.affineTransform, (CGFloat) MathUtils::degreesToRadians(degrees));

    _degrees = degrees;

    self->_planImageView.center = _center;

//    NSLog(@"%@", NSStringFromCGRect(_planImageView.frame));
}

编辑

由于答案,我改写了程序,现在它开始工作了!

- (void)rotatePlanWithDegrees:(double)degrees
{
    double newWidth =
            _initialWidth  * abs(cos(MathUtils::degreesToRadians(degrees))) +
            _initialHeight * abs(sin(MathUtils::degreesToRadians(degrees)));
    double newHeight =
            _initialWidth  * abs(sin(MathUtils::degreesToRadians(degrees))) +
            _initialHeight * abs(cos(MathUtils::degreesToRadians(degrees)));

    CGFloat scale = (CGFloat) MIN(
            self.planImageScrollView.frame.size.width / newWidth,
            self.planImageScrollView.frame.size.height / newHeight);

    CGAffineTransform rotationTransform = CGAffineTransformMakeRotation((CGFloat) MathUtils::degreesToRadians(degrees));
    CGAffineTransform scaleTransform  = CGAffineTransformMakeScale(scale, scale);
    _planImageView.layer.affineTransform = CGAffineTransformConcat(rotationTransform, scaleTransform);

    self->_planImageView.center = _center;
}