ios - CGRect在Swift中更改原点

https://drive.google.com/file/d/1Nd6q9OmDppJrxjZIRODzffVDiBXKnB_e/view?usp=sharing
我想改变“原点”的位置，就像一张用来合成水印的图片。
下面是我的代码。

var watermark = UIImage(named: "logo.png")
var newHeight = filteredImage.image?.size.height
var newWidth = filteredImage.image?.size.width

UIGraphicsBeginImageContext(CGSize(width:newWidth!, height:newHeight!))

watermark.draw(in: CGRect(x:-0, y:-0, width:400, height:300))

let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

watermark = newImage!

filter = CIFilter(name: "CISourceOverCompositing")
filter!.setValue(CIImage(image: watermark), forKey: "inputImage")
filter!.setValue(coreImage1, forKey: "inputBackgroundImage")

我该如何更改代码？

最佳答案

如果要将水印置于右下角，请使用：

var watermark = UIImage(named: "logo.png")!
var newSize = filteredImage.image.size

UIGraphicsBeginImageContext(newSize)

watermark.draw(in: CGRect(
    x: newSize.width - watermark.image.width,
    y: newSize.height - watermark.image.height,
    width: watermark.image.width,
    height: watermark.image.height
))

...

改变原点是可能的，但在这种情况下是不切实际的。