如何在 UIButton 中居中图像而不在 Swift 中双向拉伸? [英] How to center an image inside an UIButton without stretching in both direction in Swift?

问题描述

我正在制作一个自定义键盘，我需要在 shift 按钮内居中显示 shift 图标的图像.图像为 100 像素 x 100 像素.

I am making a custom keyboard and I need to centre the image of the shift icon inside the shift button. The image is 100px x 100px.

但是，纵向的按钮框架是36pt x 38pt，横向是68pt x 32pt.我尝试使用按钮图像插入属性来使图像居中.但是，它没有这样做.

However, the button frame in portrait is 36pt x 38pt, and in landscape, it is 68pt x 32pt. I have tried using button image inset property to centre the image. However, it does not does so.

我自己尝试并将图像边缘插入设置为 (25,25,25,25)，图像以两种尺寸居中.但是，图标变得太小而无法看到.

I tried myself and set the image edge insets to (25,25,25,25), the image centres in both sizes. However, the icon becomes too small to see.

shiftButton.setImage(UIImage(named: "shift"), forState: .Normal)

shiftButton.imageEdgeInsets = UIEdgeInsetsMake(0,0,0,0)

我正在以编程方式制作按钮.而且，我需要按钮来缩放保持其纵横比，即 1:1.它的最大宽度或高度总是与按钮本身的高度相关联.图像宽度/高度应为按钮高度的最大值.而且，它不应该以任何方式拉伸以扭曲图标.但是，按钮本身可以拉伸.

I am making the button programatically. And, I need the button to scale maintaining its aspect ratio i.e. 1:1. Its maximum width or height is always tied to the button's height itself. The image width/height should be maximum of button's height. And, it should not stretch in any way to distort the icon. However, the button itself can stretch.

我需要根据按钮框架缩放图像，但要保持其纵横比.而且，它可以缩小或放大，但应始终保持 1:1 的纵横比.

I need the image to scale according to button frame but maintain its aspect ratio. And, it can down scale or up scale, but should always maintain the 1:1 aspect ratio.

对解决这个问题有什么建议吗?

Any suggestions for solving this problem?

推荐答案

终于找到了解决方案.您必须为 UIButton 内的图像设置内容模式.

Finally a solution came through. You must set the content mode for the image inside the UIButton.

解决方案是在按钮内使用前景图像时更新 Image 的 contentMode 以及UIButton.

The solution is to update the contentMode of the Image when you are using a foreground image inside a button along with the contentMode of the UIButton.

shiftButton.contentMode = .Center
shiftButton.imageView?.contentMode = .ScaleAspectFit

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