ios - 在iOS中以编程方式适合方面？

Question

我想使用方面适合选项将一个视图插入另一个视图。但我不能仅仅contentMode因为某些原因而设置。

您能否通过CGRect根据外部调整内部大小来提供解决方案CGRect？

是的，有很多类似的问题，但没有人提供这样的解决方案。

Answer 1

我写了一个应该实现你想要的功能。

它将返回CGRect给定的innerRect，在缩放它以适应给定的 后outerRect，同时保持纵横比。将innerRect在outerRect.

static inline CGRect aspectFitRect(CGRect outerRect, CGRect innerRect) {

    // the width and height ratios of the rects
    CGFloat wRatio = outerRect.size.width/innerRect.size.width;
    CGFloat hRatio = outerRect.size.height/innerRect.size.height;

    // calculate scaling ratio based on the smallest ratio.
    CGFloat ratio = (wRatio < hRatio)? wRatio:hRatio;

    // The x-offset of the inner rect as it gets centered
    CGFloat xOffset = (outerRect.size.width-(innerRect.size.width*ratio))*0.5;

    // The y-offset of the inner rect as it gets centered
    CGFloat yOffset = (outerRect.size.height-(innerRect.size.height*ratio))*0.5;

    // aspect fitted origin and size
    CGPoint innerRectOrigin = {xOffset+outerRect.origin.x, yOffset+outerRect.origin.y};
    CGSize innerRectSize = {innerRect.size.width*ratio, innerRect.size.height*ratio};

    return (CGRect){innerRectOrigin, innerRectSize};
}

然后，您可以像这样使用它：

// outer rect
CGRect outerRect = CGRectMake(0, 100, self.view.bounds.size.width, 500);

// outer rect's view
UIView* v = [[UIView alloc] initWithFrame:outerRect];
v.backgroundColor = [UIColor greenColor];
[self.view addSubview:v];

// inner rect
CGRect innerRect = CGRectMake(0, 0, self.view.bounds.size.width*2, 500);
CGRect scaledInnerRect = aspectFitRect(v.bounds, innerRect);

// inner rect's view
UIView* v1 = [[UIView alloc] initWithFrame:scaledInnerRect];
v1.backgroundColor = [UIColor redColor];
[v addSubview:v1];

在这种情况下， 对innerRect来说太宽了outerRect，所以它会根据它的宽度进行缩放。

这里，红色区域是innerRect，绿色区域是outerRect。它们最初具有相同的高度，但是在按比例缩小（因为它是原来的 2 倍）之后，innerRect现在的高度只有outerRect.

这里innerRect将作为子视图添加到outerRect. 如果要将它们添加到同一个超级视图中，可以将outerRect's传递frame给函数，而不是bounds.

Answer 2

下面是 CGSize 和 CGRect 扩展，分别用于将一个尺寸拟合到另一个尺寸内，并将一个矩形拟合到另一个矩形内：

extension CGSize
{
    func sizeThatFitsSize(_ aSize: CGSize) -> CGSize
    {
        let width = min(self.width * aSize.height / self.height, aSize.width)
        return CGSize(width: width, height: self.height * width / self.width)
    }
}

extension CGRect
{
    func rectThatFitsRect(_ aRect:CGRect) -> CGRect
    {
        let sizeThatFits = self.size.sizeThatFitsSize(aRect.size)

        let xPos = (aRect.size.width - sizeThatFits.width) / 2
        let yPos = (aRect.size.height - sizeThatFits.height) / 2

        let ret = CGRect(x: xPos, y: yPos, width: sizeThatFits.width, height: sizeThatFits.height)
        return ret
    }
}

Answer 3

    // Your First View
    UIView *firstView = self;

    // Your second View
    UIView *secondView = [[UIView alloc] initWithFrame:CGRectZero]; change
    newSubview.translatesAutoresizingMaskIntoConstraints = NO;
    [containerView addSubview:newSubview];

    // Top Constraint
    [firstView addConstraint:[NSLayoutConstraint constraintWithItem:secondView
                                                              attribute:NSLayoutAttributeTop
                                                              relatedBy:NSLayoutRelationEqual
                                                                 toItem:firstView
                                                              attribute:NSLayoutAttributeTop
                                                             multiplier:1.0
                                                               constant:0.0]];
     // Leading Constraint                                                      
    [firstView addConstraint:[NSLayoutConstraint constraintWithItem:secondView
                                                              attribute:NSLayoutAttributeLeading
                                                              relatedBy:NSLayoutRelationEqual
                                                                 toItem:firstView
                                                              attribute:NSLayoutAttributeLeading
                                                             multiplier:1.0
                                                               constant:0.0]];
    // Bottom Constraint
    [firstView addConstraint:[NSLayoutConstraint constraintWithItem:secondView
                                                              attribute:NSLayoutAttributeBottom
                                                              relatedBy:NSLayoutRelationEqual
                                                                 toItem:firstView
                                                              attribute:NSLayoutAttributeBottom
                                                             multiplier:1.0
                                                               constant:0.0]];
    // Trailing Constraint
    [firstView addConstraint:[NSLayoutConstraint constraintWithItem:secondView
                                                              attribute:NSLayoutAttributeTrailing
                                                              relatedBy:NSLayoutRelationEqual
                                                                 toItem:firstView
                                                              attribute:NSLayoutAttributeTrailing
                                                             multiplier:1.0
                                                               constant:0.0]];

}

我认为这对你有帮助。