方面是否可以通过编程以适应iOS? [英] Aspect fit programmatically in iOS?

问题描述

我想使用宽高比选项将一个视图插入另一个视图.但是由于某些原因，我不能只设置contentMode.

I want to insert one view into another with aspect fit option. But I can't just set contentMode for some reasons.

您能否通过根据外部CGRect调整内部CGRect的大小来提供解决方案?

Could you provide a solution via resizing of the inner CGRect according to the outer CGRect?

是的，有很多类似的问题，但是没有人提供这样的解决方案.

And yes, there are a lot of similar questions but no one provides such solution.

推荐答案

我写了一个应该可以实现您想要的功能的函数.

在缩放比例使其适合给定outerRect的同时，它会返回给定innerRect的CGRect，同时保持宽高比. innerRect将位于outerRect的中心.

I wrote a function that should achieve what you desire.

It will return the CGRect of a given innerRect, after scaling it to fit within a given outerRect, while maintaining aspect ratio. The innerRect will be centered within the 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，innerRect对于outerRect而言太宽，因此将根据其宽度进行缩放.

In this case, the innerRect is too wide for the outerRect, so it will be scaled according to it's width.

在这里，红色区域是innerRect，绿色区域是outerRect.最初它们的高度相同，但是按比例缩小(宽度是原来的2倍) )，现在innerRect的高度是outerRect的一半.

Here, the red area is the innerRect and the green area is the outerRect. They both originally had the same height, but after being scaled down (as it was 2x as wide), the innerRect now has half the height of the outerRect.

此处，innerRect作为子视图添加到了outerRect. 如果要将它们添加到同一超级视图中，可以将outerRect的frame传递给函数，而不是bounds.

Here the innerRect is added as a subview to the outerRect. If you want to add them to the same superview, you can pass the outerRect's frame into the function, rather than the bounds.

这篇关于方面是否可以通过编程以适应iOS?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！