Merge Two Image on to one Image programmatically in iphone

Question

Hello I am developing the application which requires to merge two Image , My image size are 320*240 by merging both Image I want the size to be 320 * 480 . How can i do this

Answer 1

To avoid degrading image quality, use UIGraphicsBeginImageContextWithOptions.

If you specify a value of 0.0, the scale factor is set to the scale factor of the device’s main screen.

UIImage *image1 = [UIImage imageNamed:@"image1.png"];
UIImage *image2 = [UIImage imageNamed:@"image2.png"];

CGSize size = CGSizeMake(image1.size.width, image1.size.height + image2.size.height);

UIGraphicsBeginImageContextWithOptions(size, false, 0.0) // Use this call

[image1 drawInRect:CGRectMake(0,0,size.width, image1.size.height)];
[image2 drawInRect:CGRectMake(0,image1.size.height,size.width, image2.size.height)];

UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

//Add image to view
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, finalImage.size.width, finalImage.size.height)];
imageView.image = finalImage;
[self.view addSubview:imageView];

Answer 2

Swift 3:

accepts an images array and returns an image of the images one on top of the other takes max sizes into consideration so it's losless

func combineTopToBottom(imagesArray:[UIImage]) -> UIImage? {
    var dimensions = CGSize(width: 0.0, height: 0.0)
    for image in imagesArray {
        dimensions.width = max(dimensions.width, image!.size.width)
        dimensions.height += max(dimensions.height, image!.size.height)
    }

    UIGraphicsBeginImageContext(dimensions)

    var lastY = CGFloat(0.0)
    for image in imagesArray {
        image?.draw(in:CGRect(x: 0, y: lastY, width: dimensions.width, height: image!.size.height))
        lastY += image!.size.height
    }

    let finalImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    return finalImage
}

Answer 3

Just tested this, create your context based on the sizes of the images you are working with and draw them on top of each other (this assumes they are the same width):

UIImage *image1 = [UIImage imageNamed:@"image1.png"];
UIImage *image2 = [UIImage imageNamed:@"image2.png"];

CGSize size = CGSizeMake(image1.size.width, image1.size.height + image2.size.height);

UIGraphicsBeginImageContext(size);

[image1 drawInRect:CGRectMake(0,0,size.width, image1.size.height)];
[image2 drawInRect:CGRectMake(0,image1.size.height,size.width, image2.size.height)];

UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

//Add image to view
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, finalImage.size.width, finalImage.size.height)];
imageView.image = finalImage;
[self.view addSubview:imageView];

Answer 4

I think you must get contexts of ypur images and then marge it.

UIImage *eyes = [UIImage imageNamed:@"eyes"];
    UIGraphicsBeginImageContext(CGSizeMake(m, n));
    CGContextRef context1 = UIGraphicsGetCurrentContext(); 

    UIImage *mouth = [UIImage imageNamed:@"mouth"];
    UIGraphicsBeginImageContext(CGSizeMake(m, n));
    CGContextRef context2 = UIGraphicsGetCurrentContext(); 

Merge by drawing context with different bounds

Answer 5

#pragma mark - merging two images
-(void)mergeimage :(UIImage*)firstImage withImage:(UIImage*)secondImage{



    CGSize size = CGSizeMake(MAX(firstImage.size.width, secondImage.size.width), MAX(firstImage.size.height, secondImage.size.height));


    UIGraphicsBeginImageContext(size);


    [firstImage drawInRect:CGRectMake(self.view.frame.origin.x,self.view.frame.origin.y,size.width/2,size.height)];


    [secondImage drawInRect:CGRectMake(self.view.frame.origin.x+(size.width/2),self.view.frame.origin.y,size.width/2,size.height)];

    UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();


    UIGraphicsEndImageContext();
}

Answer 6

This implementation works for variadic arguments, so you can pass an unlimited number of images to merge vertically:

public static func mergeVertically(images: UIImage...) -> UIImage? {
    let maxWidth = images.reduce(0.0) { max($0, $1.size.width) }
    let totalHeight = images.reduce(0.0) { $0 + $1.size.height }

    UIGraphicsBeginImageContextWithOptions(CGSize(width: maxWidth, height: totalHeight), false, 0.0)
    defer {
        UIGraphicsEndImageContext()
    }

    let _ = images.reduce(CGFloat(0.0)) {
        $1.draw(in: CGRect(origin: CGPoint(x: 0.0, y: $0), size: $1.size))
        return $0 + $1.size.height
    }

    return UIGraphicsGetImageFromCurrentImageContext()
}