ios - 如何在 swift 中对 UIView 的 AspectFit 背景图像进行 AspectFit？

Question

当我将背景图像设置为图案图像时，图像会被拉伸(stretch)，所以我想将此图案图像设置为纵横比适合，如何才能做到这一点？

 let Image1 = UIImage(named: KeyboardBG_image)
    UIGraphicsBeginImageContext(keyboardview.frame.size);
    Image1?.draw(in: keyboardview.bounds);
    let image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

self.view.backgroundColor = UIColor(patternImage: image!)

谢谢..

Answer 1

AVFoundation 中有一种方法可以帮助您创建特定大小的矩形图像，同时保持纵横比。这将根据您提供的尺寸计算矩形尺寸，我使用了最大高度，因为原始图像是横向图像。

/* create the image at original size */
let image1 = UIImage(named: "Landscape-1276x800.jpg")!

/*
 * create bounding rect with largest possible height based on width
 * this will get you the aspect height for the specified width
 */
let boundingRect = CGRect(x: 0, y: 0, width: 200, height:CGFloat.greatestFiniteMagnitude)

/*
 * Returns a scaled CGRect that maintains the aspect ratio specified
 * by a CGSize within a bounding CGRect
 */
let aspectRect = AVMakeRect(aspectRatio: image1.size, insideRect: boundingRect)

/* 
 * create a UIGraphicsImageRenderer to draw the image, this replaces all
 * the  UIGraphicsContext stuff that was used to draw images
 */
let renderer = UIGraphicsImageRenderer(size: aspectRect.size)

/*
 * WARNING be careful about the origin points, if the result of the calculation 
 * is an exponential value like 8.988465674311579e+307, then the image won't draw. 
 * To be safe I set the origin to .zero
 */
let img = renderer.image { (context) in
    image1.draw(in: CGRect(origin: .zero, size: aspectRect.size))
}