How to scale an image to a frame?

Question

Is it possible to scale a UIImage to the size of the frame? Take a big image and "force it in" the smaller box.

Please provide an example

Answer 1

If you are actually talking about changing the UIImage and not just changing the display frame, which can be done as described by Mark, by changing the UIViewContentMode of the UIImageView, you can change the size of the actual image with the following UIImage extension (taken from this source)

- (UIImage*)imageByScalingAndCroppingForSize:(CGSize)targetSize
{
    UIImage *sourceImage = self;
    UIImage *newImage = nil;        
    CGSize imageSize = sourceImage.size;
    CGFloat width = imageSize.width;
    CGFloat height = imageSize.height;
    CGFloat targetWidth = targetSize.width;
    CGFloat targetHeight = targetSize.height;
    CGFloat scaleFactor = 0.0;
    CGFloat scaledWidth = targetWidth;
    CGFloat scaledHeight = targetHeight;
    CGPoint thumbnailPoint = CGPointMake(0.0,0.0);

    if (CGSizeEqualToSize(imageSize, targetSize) == NO) 
    {
        CGFloat widthFactor = targetWidth / width;
        CGFloat heightFactor = targetHeight / height;

        if (widthFactor > heightFactor) 
            scaleFactor = widthFactor; // scale to fit height
        else
            scaleFactor = heightFactor; // scale to fit width
        scaledWidth  = width * scaleFactor;
        scaledHeight = height * scaleFactor;

        // center the image
        if (widthFactor > heightFactor)
        {
            thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5; 
        }
        else 
            if (widthFactor < heightFactor)
            {
                thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;
            }
    }       

    UIGraphicsBeginImageContext(targetSize); // this will crop

    CGRect thumbnailRect = CGRectZero;
    thumbnailRect.origin = thumbnailPoint;
    thumbnailRect.size.width  = scaledWidth;
    thumbnailRect.size.height = scaledHeight;

    [sourceImage drawInRect:thumbnailRect];

    newImage = UIGraphicsGetImageFromCurrentImageContext();
    if(newImage == nil) 
        NSLog(@"could not scale image");

    //pop the context to get back to the default
    UIGraphicsEndImageContext();
    return newImage;
}

Answer 2

possible dupe of this question: How to scale a UIImageView proportionally?

I'll copy over the accepted answer text as well. Assuming your frame is a uiview:

imageView.contentMode = UIViewContentModeScaleAspectFit; will do what you want.

from the docs, here are the other scaling options

UIViewContentMode

Specifies how a view adjusts its content when its size changes.
typedef enum {
   UIViewContentModeScaleToFill,
   UIViewContentModeScaleAspectFit,
   UIViewContentModeScaleAspectFill,
   UIViewContentModeRedraw,
   UIViewContentModeCenter,
   UIViewContentModeTop,
   UIViewContentModeBottom,
   UIViewContentModeLeft,
   UIViewContentModeRight,
   UIViewContentModeTopLeft,
   UIViewContentModeTopRight,
   UIViewContentModeBottomLeft,
   UIViewContentModeBottomRight,
} UIViewContentMode;

apple Documentation here: http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIImageView_Class/Reference/Reference.html