Resizing UIImage height while keeping it's aspect ratio (iOS) [duplicate] - ios

Question

This question already has answers here:
Resize UIImage by keeping Aspect ratio and width
(19 answers)
Closed 7 years ago.
I'm using the UIImagePickerController to chose an image from my library and uploading it to Parse. How can I resize my image's height only? I want the image to keep it's aspect ratio but I don't want the height to be taller than 1000px.
Right now I'm resizing both the width and height to a fixed number with this code:
ViewController.h
- (UIImage *)resizeImage:(UIImage *)image toWidth:(float)width andHeight:(float)height;
ViewController.h
- (UIImage *)resizeImage:(UIImage *)image toWidth:(float)width andHeight:(float)height {
CGSize newSize = CGSizeMake(width, height);
CGRect newRectangle = CGRectMake(0, 0, width, height);
UIGraphicsBeginImageContext(newSize);
[self.image drawInRect:newRectangle];
UIImage *resizedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return resizedImage;
}
- (IBAction)createProduct:(id)sender {
UIImage *newImage = [self resizeImage:self.image toWidth:750.0f andHeight:1000.0f];
NSData *imageData = UIImagePNGRepresentation(newImage);
PFFile *imageFile = [PFFile fileWithName:#"image.jpg" data:imageData];
}
Thanks.

Answer 1

+(UIImage*)imageWithImage: (UIImage*) sourceImage scaledToHeight: (float) i_height
{
float oldHeight = sourceImage.size.height;
float scaleFactor = i_height / oldHeight;
float newWidth = sourceImage.size.width* scaleFactor;
float newHeight = oldHeight * scaleFactor;
UIGraphicsBeginImageContext(CGSizeMake(newWidth, newHeight));
[sourceImage drawInRect:CGRectMake(0, 0, newWidth, newHeight)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}

Answer 2

You will have to get the aspect ration of the original dimensions and multiply that with your new height
Pseudocode
if (height > 1000){
aspectRatio = width/height;
height = 1000;
width = height * aspectRatio
}
- (IBAction)createProduct:(id)sender {
UIImage *newImage;
if (self.image.size.height > 1000){
CGFloat aspectRatio = self.image.size.width/self.image.size.height;
CGFloat height = 1000;
CGFloat width = height * aspectRatio;
newImage = [self resizeImage:self.image toWidth:width andHeight:height];
} else {
newImage = self.image;
}
NSData *imageData = UIImagePNGRepresentation(newImage);
PFFile *imageFile = [PFFile fileWithName:#"image.jpg" data:imageData];
}