Resizing UIImage in UIImageView

Question

I'm trying to create a UIPickerView with some images in it, but I can't seem to figure out how to get the images to fit in the view (right now they're too large and are overlapping each other).

I'm trying to use a function to resize each image when it's drawn, but I'm getting errors when the function is called, although the program compiles and runs fine (with the exception of the image not resizing). The resizing function and initialization functions are:

-(UIImage *)resizeImage:(UIImage *)image width:(int)width height:(int)height {
    NSLog(@"resizing");
    CGImageRef imageRef = [image CGImage];
    CGImageAlphaInfo alphaInfo = CGImageGetAlphaInfo(imageRef);
    
    //if (alphaInfo == kCGImageAlphaNone)
    alphaInfo = kCGImageAlphaNoneSkipLast;
    
    CGContextRef bitmap = CGBitmapContextCreate(NULL, width, height, CGImageGetBitsPerComponent(imageRef), 
                                                4 * width, CGImageGetColorSpace(imageRef), alphaInfo);
    CGContextDrawImage(bitmap, CGRectMake(0, 0, width, height), imageRef);
    CGImageRef ref = CGBitmapContextCreateImage(bitmap);
    UIImage *result = [UIImage imageWithCGImage:ref];
    
    CGContextRelease(bitmap);
    CGImageRelease(ref);
    
    return result;  
}

- (void)viewDidLoad {
    UIImage *h1 = [UIImage imageNamed:@"h1.png"];
    
    h1 = [self resizeImage:h1 width:50 height: 50];
    
    UIImageView *h1View = [[UIImageView alloc] initWithImage:h1];
        
    NSArray *imageViewArray = [[NSArray alloc] initWithObjects:
                                h1View, nil];
    
    NSString *fieldName = [[NSString alloc] initWithFormat:@"column1"];
    [self setValue:imageViewArray forKey:fieldName];
    [fieldName release];
    [imageViewArray release];
        
    [h1View release];
}

Console Output:

TabTemplate[29322:207] resizing

TabTemplate[29322] : CGBitmapContextCreate: unsupported colorspace

TabTemplate[29322] : CGContextDrawImage: invalid context

TabTemplate[29322] : CGBitmapContextCreateImage: invalid context

I can't figure out what's going wrong. Any help is greatly appreciated.

Did you check if the value returned by CGImageGetColorSpace(imageRef) is one of the values accepted by CGBitmapContextCreate? — Bemmu, Jun 17 '11 at 05:20

score 17 · Accepted Answer · edited May 23 '17 at 12:34

17

You don't require to resize your UIImage if you use the contentMode property of UIImageView.

    myImageView.contentMode  = UIViewContentModeScaleAspectFit;

Or if you still want to resize your UIImage, Have look at below SO post.

resizing a UIImage without loading it entirely into memory?

UIImage: Resize, then Crop

edited May 23 '17 at 12:34

Community

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answered Jun 17 '11 at 05:35

Jhaliya - Praveen Sharma

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score 14 · Answer 2 · edited May 13 '12 at 23:58

14

Use below to scale the image using aspect ratio, then clip the image to imageview's bounds.

imageView.contentMode = UIViewContentModeScaleAspectFill;
imageView.clipsToBounds = YES;

edited May 13 '12 at 23:58

max_

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answered Mar 06 '12 at 08:58

trillions

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Thank you for this answer. `clipsToBounds` was what I was missing - huge help! – StoriKnow Mar 23 '13 at 20:54
1

This will correctly fill the view with the image while keeping its aspect ratio but hides what doesn't fit in the area. – Ammar Mujeeb May 09 '17 at 06:26

score 0 · Answer 3 · answered Jul 26 '16 at 14:09

0

In case of swift

imageView.contentMode = .ScaleAspectFill
imageView.clipsToBounds = true

answered Jul 26 '16 at 14:09

Ghulam Rasool

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score -1 · Answer 4 · answered Nov 18 '16 at 20:49

-1

UIImage *image = [UIImage imageNamed:@"myImage"];
    [image drawInRect: destinationRect];
    UIImage *thumbnail = UIGraphicsGetImageFromCurrentImageContext();
UIImageWriteToSavedPhotosAlbum(image,nil,nil,nil);

answered Nov 18 '16 at 20:49

James Bush

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Resizing UIImage in UIImageView

4 Answers4