Resize UImage

UIImage can be re sized or scaled to fit in frame or to reduce size to send over network. Below is the utility function that takes UIImage and target dimensions (in terms of CGSize), and returns resized UIImage.

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Example - 1

UIImage *small = [UIImage imageWithCGImage:original.CGImage scale:0.25 orientation:original.imageOrientation];

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Example - 2

UIGraphicsBeginImageContext(CGSizeMake(100,100));

 [imgView.image drawInRect:CGRectMake(0, 0,100,100)];
 UIImage* scaledImage = UIGraphicsGetImageFromCurrentImageContext();
 imgView.image = scaledImage;
 UIGraphicsEndImageContext();

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Include QuartzCore.FrameWork in project
Import <QuartzCore/QuartzCore.h> in implementation file

Example - 3

- (UIImage *)resizeImageToSize:(CGSize)targetSize

{

UIImage *sourceImage = self.imageToFitInBackground;

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;

else

scaleFactor = heightFactor;

scaledWidth  = width * scaleFactor;

scaledHeight = height * scaleFactor;

// make image center aligned

if (widthFactor < heightFactor)

{

thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5;

}

else if (widthFactor > heightFactor)

{

thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;

}

}

UIGraphicsBeginImageContext(targetSize);

CGRect thumbnailRect = CGRectZero;

thumbnailRect.origin = thumbnailPoint;

thumbnailRect.size.width  = scaledWidth;

thumbnailRect.size.height = scaledHeight;

[sourceImage drawInRect:thumbnailRect];

newImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

if(newImage == nil)

NSLog(@"could not scale image");

return newImage ;

}

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Example - 4

- (UIImage *)scaleAndRotateImage:(UIImage *)image
{
    static int kMaxResolution = 300;
   
    CGImageRef imgRef = image.CGImage;
    CGFloat widtha = CGImageGetWidth(imgRef);
    CGFloat heighta = CGImageGetHeight(imgRef);
   
    CGAffineTransform transform = CGAffineTransformIdentity;
    CGRect bounds = CGRectMake(0, 0, widtha, heighta);
    if (widtha > kMaxResolution || heighta > kMaxResolution) {
        CGFloat ratio = widtha/heighta;
        if (ratio > 1) {
            bounds.size.width = kMaxResolution;
            bounds.size.height = bounds.size.width / ratio;
        } else {
            bounds.size.height = kMaxResolution;
            bounds.size.width = bounds.size.height * ratio;
        }
    }
   
    CGFloat scaleRatio = bounds.size.width / widtha;
    CGSize imageSize = CGSizeMake(CGImageGetWidth(imgRef), CGImageGetHeight(imgRef));
    CGFloat boundHeight;
   
    UIImageOrientation orient = image.imageOrientation;
    switch(orient) {
        case UIImageOrientationUp:
            transform = CGAffineTransformIdentity;
            break;
        case UIImageOrientationUpMirrored:
            transform = CGAffineTransformMakeTranslation(imageSize.width, 0.0);
            transform = CGAffineTransformScale(transform, -1.0, 1.0);
            break;
        case UIImageOrientationDown:
            transform = CGAffineTransformMakeTranslation(imageSize.width, imageSize.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformMakeTranslation(0.0, imageSize.height);
            transform = CGAffineTransformScale(transform, 1.0, -1.0);
            break;
        case UIImageOrientationLeftMirrored:
            boundHeight = bounds.size.height;
            bounds.size.height = bounds.size.width;
            bounds.size.width = boundHeight;
            transform = CGAffineTransformMakeTranslation(imageSize.height, imageSize.width);
            transform = CGAffineTransformScale(transform, -1.0, 1.0);
            transform = CGAffineTransformRotate(transform, 3.0 * M_PI / 2.0);
            break;
        case UIImageOrientationLeft:
            boundHeight = bounds.size.height;
            bounds.size.height = bounds.size.width;
            bounds.size.width = boundHeight;
            transform = CGAffineTransformMakeTranslation(0.0, imageSize.width);
            transform = CGAffineTransformRotate(transform, 3.0 * M_PI / 2.0);
            break;
        case UIImageOrientationRightMirrored:
            boundHeight = bounds.size.height;
            bounds.size.height = bounds.size.width;
            bounds.size.width = boundHeight;
            transform = CGAffineTransformMakeScale(-1.0, 1.0);
            transform = CGAffineTransformRotate(transform, M_PI / 2.0);
            break;
        case UIImageOrientationRight:
            boundHeight = bounds.size.height;
            bounds.size.height = bounds.size.width;
            bounds.size.width = boundHeight;
            transform = CGAffineTransformMakeTranslation(imageSize.height, 0.0);
            transform = CGAffineTransformRotate(transform, M_PI / 2.0);
            break;
        default:
            [NSException raise:NSInternalInconsistencyException format:@"Invalid image orientation"];
    }
   
    UIGraphicsBeginImageContext(bounds.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    if (orient == UIImageOrientationRight || orient == UIImageOrientationLeft) {
        CGContextScaleCTM(context, -scaleRatio, scaleRatio);
        CGContextTranslateCTM(context, -heighta, 0);
    } else {
        CGContextScaleCTM(context, scaleRatio, -scaleRatio);
        CGContextTranslateCTM(context, 0, -heighta);
    }
    CGContextConcatCTM(context, transform);
    CGContextDrawImage(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, widtha, heighta), imgRef);
    UIImage *imageCopy = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
   
   
    UIGraphicsBeginImageContext(CGSizeMake(250.0f,250.0f));
    [imageCopy drawInRect:CGRectMake(0, 0, 250, 250)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();   
    UIGraphicsEndImageContext();
    // return newImage;
   
   
    return newImage;
}



UIImage Utility 
UIImage 

Attch UIToolbar with UITextfield key-board.

As of iOS 3.2 there's a new way to achieve this effect:
UITextFields and UITextViews have an inputAccessoryView property, which you can set to any view, that is automatically displayed above and animated with the keyboard.
Note that the view you use should neither be in the view hierarchy elsewhere, nor should you add it to some superview, this is done for you.
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Code Example:

UIToolbar* numberToolbar = [[UIToolbar alloc]initWithFrame:CGRectMake(0, 0, 320, 50)];
    numberToolbar.barStyle = UIBarStyleBlack;
    numberToolbar.items = [NSArray arrayWithObjects:
                           [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil],
                           [[UIBarButtonItem alloc]initWithTitle:@"Done" style:UIBarButtonItemStyleDone target:self action:@selector(doneWithNumberPad)],
                           nil];
    [numberToolbar sizeToFit];
    textField.inputAccessoryView = numberToolbar; //textfield is reference for your text box.

-(void)doneWithNumberPad
{
    [textField resignFirstResponder];
}









More Detail

Reload UITableView particular row with animation.

To animate a batch insertion and deletion of rows and sections, call the insertion and deletion methods within an animation block defined by successive calls to beginUpdates and endUpdates. If you don’t call the insertion and deletion methods within this block, row and section indexes may be invalid. beginUpdates...endUpdates blocks are not nestable.
At the conclusion of a block—that is, after endUpdates returns—the table view queries its data source and delegate as usual for row and section data. Thus the collection objects backing the table view should be updated to reflect the new or removed rows or sections.
The reloadSections:withRowAnimation: and reloadRowsAtIndexPaths:withRowAnimation: methods, which were introduced in iPhone OS 3.0, are related to the methods discussed above. They allow you to request the table view to reload the data for specific sections and rows instead of loading the entire visible table view by calling reloadData.

 Example Code:

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 NSIndexPath *myIP = [NSIndexPath indexPathForRow:0 inSection:0];//Indexpath for row which want to reload
   
    [tableView canCancelContentTouches];
    [tableView beginUpdates];
    [tableView reloadRowsAtIndexPaths:[NSArray arrayWithObject:myIP]
                 withRowAnimation:UITableViewRowAnimationRight];//You can change animation option.
    [tableView endUpdates];