How to merge two UIImages while keeping the aspect ratio and size?

Question

The code is added to Github to let you understand the real problem. This is the hierarchy: ``` -- ViewController.View P [width: 375, height: 667] ---- UIImageView A [width: 375, height: 667] Name: imgBackground [A is holding an image of size(1287,1662)] ---- UIImageView B [width: 100, height: 100] Name: imgForeground [B is holding an image of size(2400,982)] ``` I am trying to merge A with B but the result is stretched. This is the merge code: ``` func mixImagesWith(frontImage:UIImage?, backgroundImage: UIImage?, atPoint point:CGPoint, ofSize signatureSize:CGSize) -> UIImage { let size = self.imgBackground.frame.size UIGraphicsBeginImageContextWithOptions(size, false, UIScreen.main.scale) backgroundImage?.draw(in: CGRect.init(x: 0, y: 0, width: size.width, height: size.height)) frontImage?.draw(in: CGRect.init(x: point.x, y: point.y, width: signatureSize.width, height: signatureSize.height)) let newImage:UIImage = UIGraphicsGetImageFromCurrentImageContext()! UIGraphicsEndImageContext(…

Accepted Answer

You have two bugs in your code:

You should also calculate aspect for document image to fit it into `UIImageView`. In `mergeImages()` replace:

```
img.draw(in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
```

with:

```
img.draw(in: getAspectFitFrame(sizeImgView: size, sizeImage: img.size))
```

When calculating aspect you center image horizontally/vertically if its width/height less then `UIImageView` width/height. But instead of comparing `newWidth` and `newHeight` you should compare factors:

```
if hfactor > vfactor {
    y = (sizeImgView.height - newHeight) / 2
} else {
    x = (sizeImgView.width - newWidth) / 2
}
```

How to merge two UIImages while keeping the aspect ratio and size?

Solution

Problem