How to merge two UIImages? - ios

Question

I am trying to merge two different images and create a new one. This is the way I would like to do:
I have this image (A):
It's a PNG image and I would like to merge this one with another image (B) which I took from the phone to create something like this:
I need a function who merge A with B creating C. The size must remain from the A image and the image B should auto adapt the size to fit into the polaroid (A). Is it possible to do that? Thank for your help!
UPDATE
Just one thing, the image (A) is a square and the image i took is a 16:9, how can i fix that?? If i use your function the image (B) that i took become stretched!

Answer 1

Hope this may help you,
var bottomImage = UIImage(named: "bottom.png")
var topImage = UIImage(named: "top.png")
var size = CGSize(width: 300, height: 300)
UIGraphicsBeginImageContext(size)
let areaSize = CGRect(x: 0, y: 0, width: size.width, height: size.height)
bottomImage!.draw(in: areaSize)
topImage!.draw(in: areaSize, blendMode: .normal, alpha: 0.8)
var newImage:UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
All the Best :)

Answer 2

Swift 5: Extension for UIImage
extension UIImage {
func mergeWith(topImage: UIImage) -> UIImage {
let bottomImage = self
UIGraphicsBeginImageContext(size)
let areaSize = CGRect(x: 0, y: 0, width: bottomImage.size.width, height: bottomImage.size.height)
bottomImage.draw(in: areaSize)
topImage.draw(in: areaSize, blendMode: .normal, alpha: 1.0)
let mergedImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return mergedImage
}
}

Answer 3

Swift 4 UIImage extension that enables easy image merging / overlaying.
extension UIImage {
func overlayWith(image: UIImage, posX: CGFloat, posY: CGFloat) -> UIImage {
let newWidth = size.width < posX + image.size.width ? posX + image.size.width : size.width
let newHeight = size.height < posY + image.size.height ? posY + image.size.height : size.height
let newSize = CGSize(width: newWidth, height: newHeight)
UIGraphicsBeginImageContextWithOptions(newSize, false, 0.0)
draw(in: CGRect(origin: CGPoint.zero, size: size))
image.draw(in: CGRect(origin: CGPoint(x: posX, y: posY), size: image.size))
let newImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return newImage
}
}

Answer 4

This way the overlay picture will be much cleaner:
class func mergeImages(imageView: UIImageView) -> UIImage {
UIGraphicsBeginImageContextWithOptions(imageView.frame.size, false, 0.0)
imageView.superview!.layer.renderInContext(UIGraphicsGetCurrentContext()!)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return image
}

Answer 5

Objective C version of this solution with top image re-centered logic :
-(UIImage *)getImageInclosedWithinAnotherImage
{
float innerImageSize = 20;
UIImage *finalImage;
UIImage *outerImage = [UIImage imageNamed:#"OuterImage.png"];
UIImage *innerImage = [UIImage imageNamed:#"InnerImage.png"];
CGSize outerImageSize = CGSizeMake(40, 40); // Provide custom size or size of your actual image
UIGraphicsBeginImageContext(outerImageSize);
//calculate areaSize for re-centered inner image
CGRect areSize = CGRectMake(((outerImageSize.width/2) - (innerImageSize/2)), ((outerImageSize.width/2) - (innerImageSize/2)), innerImageSize, innerImageSize);
[outerImage drawInRect:CGRectMake(0, 0, outerImageSize.width, outerImageSize.height)];
[innerImage drawInRect:areSize blendMode:kCGBlendModeNormal alpha:1.0];
finalImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return finalImage;
}

Answer 6

The upvoted answer stretches the background image changing its ratio. The solution below fixes that by rendering the image from a UIView that contains the two image views as subviews.
ANSWER YOU ARE LOOKING FOR (Swift 4):
func blendImages(_ img: UIImage,_ imgTwo: UIImage) -> Data? {
let bottomImage = img
let topImage = imgTwo
let imgView = UIImageView(frame: CGRect(x: 0, y: 0, width: 306, height: 306))
let imgView2 = UIImageView(frame: CGRect(x: 0, y: 0, width: 306, height: 306))
// - Set Content mode to what you desire
imgView.contentMode = .scaleAspectFill
imgView2.contentMode = .scaleAspectFit
// - Set Images
imgView.image = bottomImage
imgView2.image = topImage
// - Create UIView
let contentView = UIView(frame: CGRect(x: 0, y: 0, width: 306, height: 306))
contentView.addSubview(imgView)
contentView.addSubview(imgView2)
// - Set Size
let size = CGSize(width: 306, height: 306)
// - Where the magic happens
UIGraphicsBeginImageContextWithOptions(size, true, 0)
contentView.drawHierarchy(in: contentView.bounds, afterScreenUpdates: true)
guard let i = UIGraphicsGetImageFromCurrentImageContext(),
let data = UIImageJPEGRepresentation(i, 1.0)
else {return nil}
UIGraphicsEndImageContext()
return data
}
The returned image data doubles the size of the image, so set the size of the views at half the desired size.
EXAMPLE: I wanted the width and height of the image to be 612, so I set the view frames width and height to 306)
// Enjoy :)

Answer 7

Slightly modified version of answer by budidino. This implementation also handles negative posX and posY correctly.
extension UIImage {
func overlayWith(image: UIImage, posX: CGFloat, posY: CGFloat) -> UIImage {
let newWidth = posX < 0 ? abs(posX) + max(self.size.width, image.size.width) :
size.width < posX + image.size.width ? posX + image.size.width : size.width
let newHeight = posY < 0 ? abs(posY) + max(size.height, image.size.height) :
size.height < posY + image.size.height ? posY + image.size.height : size.height
let newSize = CGSize(width: newWidth, height: newHeight)
UIGraphicsBeginImageContextWithOptions(newSize, false, 0.0)
let originalPoint = CGPoint(x: posX < 0 ? abs(posX) : 0, y: posY < 0 ? abs(posY) : 0)
self.draw(in: CGRect(origin: originalPoint, size: self.size))
let overLayPoint = CGPoint(x: posX < 0 ? 0 : posX, y: posY < 0 ? 0 : posY)
image.draw(in: CGRect(origin: overLayPoint, size: image.size))
let newImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return newImage
}
}