如何结合两个不同锚点的两个旋转来变换 UIView答案

【问题标题】：How to combine two rotations at two different anchor points to transform UIView如何结合两个不同锚点的两个旋转来变换 UIView
【发布时间】：2014-05-09 16:31:31
【问题描述】：

我想首先围绕它的左边缘旋转我的 UIView，然后围绕它的右边缘旋转。第一次旋转应该产生开门效果，一旦完成，第二次旋转应该开始。当第二次旋转完成时，效果应该就像视图在 z 平面中被推下一样。转换是手动动画的一部分，当然应该是无缝的。

凭直觉，我猜不可能使用锚点并连接发生在不同锚点的 2 个旋转（但如果我错了，请纠正我）。因此，我没有使用锚点，而是使用矩阵组合来产生“旋转”的效果。

第一次旋转很容易，但我不知道如何附加第二次。也许在应用第二次旋转之前，我应该在 y 坐标上向右平移并在 z 坐标上向下移动（使用 cos(90 - angle) * view.width 之类的东西）以到达右边缘的位置第一次旋转结束。然而我所做的尝试并没有成功。任何想法？这是我到目前为止第一次轮换的内容：

-(void) transform:(float) percentage{

    CATransform3D transform = CATransform3DIdentity;

    //here I get the angle for the 1st rotation (percentage 0 -> angle 0; percentage 0.5 -> angle 45°
    float angle = [self getFirstRotationAngle: percentage];
    CATransform3D translateToRotateAt = CATransform3DMakeTranslation(myView.frame.size.width / 2.0, 0.0, 0.0);
    CATransform3D rotation1 = CATransform3DIdentity;
    rotation1.m34 = 1.0 / -500;
    rotation1 = CATransform3DRotate(rotation1, angle, 0.0f, 1.0f, 0.0f);
    CATransform3D translateBackToRotateAt = CATransform3DMakeTranslation(-myView.frame.size.width / 2.0, 0.0, 0.0f);

    transform = CATransform3DConcat(translateToRotateAt, rotation1);
    transform = CATransform3DConcat(transform , translateBackToRotateAt);

    if (percentage > 0.5){
        angle = [self getSecondRotationAngle: percentage];

        // here I should get the second part of the transformation and concatenate it to the first part
    }

    myView.layer.transform = transform;
}

【问题讨论】：

标签： ios iphone cocoa-touch rotation transformation

【解决方案1】：

这种方法可以为你做一个转换，你的学位赋予它

func makeTransform(horizontalDegree: CGFloat, verticalDegree: CGFloat, maxVertical: CGFloat,rotateDegree: CGFloat, maxHorizontal: CGFloat) -> CATransform3D {
    var transform = CATransform3DIdentity
           
    transform.m34 = 1 / -500
    
    let xAnchor = (horizontalDegree / (2 * maxHorizontal)) + 0.5
    let yAnchor = (verticalDegree / (-2 * maxVertical)) + 0.5
    let anchor = CGPoint(x: xAnchor, y: yAnchor)
    
    setAnchorPoint(anchorPoint: anchor, forView: self.imgView)
    let hDegree  = (CGFloat(horizontalDegree) * .pi)  / 180
    let vDegree  = (CGFloat(verticalDegree) * .pi)  / 180
    let rDegree  = (CGFloat(rotateDegree) * .pi)  / 180
    transform = CATransform3DRotate(transform, vDegree , 1, 0, 0)
    transform = CATransform3DRotate(transform, hDegree , 0, 1, 0)
    transform = CATransform3DRotate(transform, rDegree , 0, 0, 1)
    
    return transform
}

func setAnchorPoint(anchorPoint: CGPoint, forView view: UIView) {
    var newPoint = CGPoint(x: view.bounds.size.width * anchorPoint.x, y: view.bounds.size.height * anchorPoint.y)
    var oldPoint = CGPoint(x: view.bounds.size.width * view.layer.anchorPoint.x, y: view.bounds.size.height * view.layer.anchorPoint.y)
    
    newPoint = newPoint.applying(view.transform)
    oldPoint = oldPoint.applying(view.transform)
    
    var position = view.layer.position
    position.x -= oldPoint.x
    position.x += newPoint.x
    
    position.y -= oldPoint.y
    position.y += newPoint.y
    
    print("Anchor: \(anchorPoint)")
    
    view.layer.position = position
    view.layer.anchorPoint = anchorPoint
}

【讨论】：