Image resizing and masking in IOS

Resize UIImage :

+(UIImage *)resizeImage:(UIImage *)image toSize:(CGSize)destSize{

    float currentHeight = image.size.height;

    float currentWidth = image.size.width;

    float liChange ;

    CGSize newSize ;

    if(currentWidth == currentHeight) // image is square

        {

             liChange = destSize.height / currentHeight;

             newSize.height = currentHeight * liChange;

             newSize.width = currentWidth * liChange;

            }

    else if(currentHeight > currentWidth) // image is landscape

         {

              liChange = destSize.width / currentWidth;

              newSize.height = currentHeight * liChange;

              newSize.width = destSize.width;

             }

    else        // image is Portrait

         {

             liChange = destSize.height / currentHeight;

             newSize.height= destSize.height;

             newSize.width = currentWidth * liChange;

             }

    

    

    UIGraphicsBeginImageContext( newSize );

    CGContextRef    context;

    UIImage      *outputImage = nil;

    

    context = UIGraphicsGetCurrentContext();

    CGContextSetInterpolationQuality(context, kCGInterpolationHigh);

    [image drawInRect:CGRectMake( 0, 0, newSize.width, newSize.height )];

    outputImage = UIGraphicsGetImageFromCurrentImageContext();

    

    UIGraphicsEndImageContext();

    

    CGImageRef imageRef;

    int x = (newSize.width == destSize.width) ? 0 : (newSize.width - destSize.width)/2;

    int y = (newSize.height == destSize.height) ? 0 : (newSize.height - destSize.height )/2;

    if ( ( imageRef = CGImageCreateWithImageInRect( outputImage.CGImage, CGRectMake(x, y, destSize.width, destSize.height) ) ) ) {

         outputImage = [[UIImage alloc] initWithCGImage: imageRef] ;

         CGImageRelease( imageRef );

        }

     

    return outputImage;

}

Mask image:

+(UIImage *)maskImage:(UIImage *)image andMaskingImage:(UIImage *)maskingImage{

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    CGImageRef maskImageRef = [maskingImage CGImage];

    CGContextRef mainViewContentContext = CGBitmapContextCreate (NULL, maskingImage.size.width, maskingImage.size.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast);

    if (mainViewContentContext==NULL)

         return NULL;

    CGFloat ratio = 0;

    ratio = maskingImage.size.width/ image.size.width;

    if(ratio * image.size.height < maskingImage.size.height) {

         ratio = maskingImage.size.height/ image.size.height;

        }

    CGRect rect1= {{0, 0}, {maskingImage.size.width, maskingImage.size.height}};

    CGRect rect2= {{-((image.size.width*ratio)-maskingImage.size.width)/2 , -((image.size.height*ratio)-maskingImage.size.height)/2}, {image.size.width*ratio, image.size.height*ratio}};

    CGContextClipToMask(mainViewContentContext, rect1, maskImageRef);

    CGContextDrawImage(mainViewContentContext, rect2, image.CGImage);

    CGImageRef newImage = CGBitmapContextCreateImage(mainViewContentContext);

    CGContextRelease(mainViewContentContext);

    UIImage *theImage = [UIImage imageWithCGImage:newImage];

    CGImageRelease(newImage);

     // return the image

    return theImage;

}

More details please visit following link

http://mobiledevelopertips.com/cocoa/how-to-mask-an-image.html

How to handle view positions when keyboard hide and show time in Iphone:

Hi all, Today i want to share with all Iphone developers.
In this post My topic is ,

 How to handle view positions  when keyboard  hide and show time in Iphone:

1)KeyBoardViewController.xib you need to set delegate to all UItextFields

2)In the  KeyBoardViewController.h file, add the following code in bold:

#import <UIKit/UIKit.h>

@interface KeyBoardViewController : UIViewController<UIScrollViewDelegate,UITextFieldDelegate>

{

    IBOutlet UIScrollView *scrollView;

    UITextField *currentTextField;

    BOOL keyboardIsShown;

}

@property (nonatomic, retain) UIScrollView *scrollView;

@end

 3)In the  KeyBoardViewController.m file, add the following code in bold:

#import "KeyBoardViewController.h"

@interface KeyBoardViewController ()

@end

@implementation KeyBoardViewController

@synthesize scrollView;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil

{

    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];

    if (self) {

        // Custom initialization

    }

    return self;

}

- (void)viewDidLoad

{

    scrollView.frame = CGRectMake(0, 0, 320, 460); 

    [scrollView setContentSize:CGSizeMake(320, 480)];

    [super viewDidLoad];

// Do any additional setup after loading the view.

}

- (void)viewDidUnload

{

    [super viewDidUnload];

    // Release any retained subviews of the main view.

}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation

{

    return (interfaceOrientation == UIInterfaceOrientationPortrait);

}

//—-before the View window appears—-

-(void) viewWillAppear:(BOOL)animated 

{

    //—-registers the notifications for keyboard—- 

    [[NSNotificationCenter defaultCenter]

     addObserver:self selector:@selector(keyboardDidShow:)

     name:UIKeyboardDidShowNotification object:self.view.window];

    [[NSNotificationCenter defaultCenter]

     addObserver:self selector:@selector(keyboardDidHide:)

     name:UIKeyboardDidHideNotification object:self.view.window];

    [super viewWillAppear:animated];

}

//—-when a

-(void) textFieldDidBeginEditing:(UITextField *)textFieldView 

{ 

    currentTextField = textFieldView;

}

//—-when the user taps on the return key on the keyboard—-

-(BOOL) textFieldShouldReturn:(UITextField *) textFieldView 

{

    [textFieldView resignFirstResponder];

    return NO;

}

//—-when a TextField view is done editing—-

-(void) textFieldDidEndEditing:(UITextField *) textFieldView 

{

    currentTextField = nil;

}

-(void) keyboardDidShow:(NSNotification *) notification 

{

    if (keyboardIsShown) return;

    NSDictionary* info = [notification userInfo];

    //—-obtain the size of the keyboard—-

    NSValue *aValue =

    [info objectForKey:UIKeyboardFrameEndUserInfoKey];

    CGRect keyboardRect =[self.view convertRect:[aValue CGRectValue] fromView:nil];

    NSLog(@"%f", keyboardRect.size.height);

    //—-resize the scroll view (with keyboard)—-

    CGRect viewFrame = [scrollView frame];

    viewFrame.size.height -= keyboardRect.size.height;

    scrollView.frame = viewFrame;

    //—-scroll to the current text field—-

    CGRect textFieldRect = [currentTextField frame];

    [scrollView scrollRectToVisible:textFieldRect animated:YES];

    keyboardIsShown = YES;

}

//—-when the keyboard disappears—-

-(void) keyboardDidHide:(NSNotification *) notification { 

    NSDictionary* info = [notification userInfo];

    //—-obtain the size of the keyboard—-

    NSValue* aValue =[info objectForKey:UIKeyboardFrameEndUserInfoKey];

    CGRect keyboardRect =[self.view convertRect:[aValue CGRectValue] fromView:nil];

    //—-resize the scroll view back to the original size // (without keyboard)—-

    CGRect viewFrame = [scrollView frame]; viewFrame.size.height += keyboardRect.size.height; scrollView.frame = viewFrame;

    keyboardIsShown = NO; 

}

//—-before the View window disappear—-

-(void) viewWillDisappear:(BOOL)animated { //—-removes the notifications for keyboard—- 

    [[NSNotificationCenter defaultCenter]removeObserver:self name:UIKeyboardDidShowNotification object:nil];

    [[NSNotificationCenter defaultCenter]removeObserver:self name:UIKeyboardDidHideNotification object:nil];

    [super viewWillDisappear:animated]; 

}

    

@end

Thank you 

time comarision

If you want to calculate only time between two times **in same day** which are formatted as "HH:MM:SS" then it is pretty much easy

Use simple HttpDateParser and take any date which have proper format

like "Tue, 27 Mar 2012 09:11:37 GMT"

here we replace only time then you will get time in millies between two times

 

    String common="Tue, 27 Mar 2012 "; //09:11:37 GMT
                   String time1="1:50:10";
                   String time2="3:30:20";
                 long startTime = HttpDateParser.parse(common+time1+" GMT");
                 System.out.println("start time is :" + startTime);
                 long endTime =  HttpDateParser.parse(common+time2+" GMT");
                 System.out.println("end time is :" + endTime);
                 long diff = endTime - startTime;
               
                 SimpleDateFormat formate=new SimpleDateFormat("HH:mm:ss");
                 String formateddate=formate.formatLocal(diff);
                 System.out.println("Difference in Houres:"+formateddate);


I got output as

    [0.0] start time is :1332813010000
    [0.0] end time is :1332819020000
    [0.0] Difference in Houres:01:40:10


**Note : If you want to calculate between two different days
Here you need to pass date format should be proper like example: "YYYY-mm-dd hh:mm:ss"**

here i provide some sample example



    import java.util.Calendar;
   
    import net.rim.device.api.i18n.SimpleDateFormat;
    import net.rim.device.api.io.http.HttpDateParser;
    import net.rim.device.api.ui.Field;
    import net.rim.device.api.ui.FieldChangeListener;
    import net.rim.device.api.ui.component.ButtonField;
    import net.rim.device.api.ui.component.LabelField;
    import net.rim.device.api.ui.container.MainScreen;
    import net.rim.device.api.ui.picker.DateTimePicker;
   
    public final class Screen1 extends MainScreen implements FieldChangeListener
    {
        /**
         * Creates a new MyScreen object
         */
        ButtonField date1;
        ButtonField date2;
        ButtonField button;
        LabelField lbl;
        DateTimePicker picker;
        String str="";
        Calendar cal;   
       
        public Screen1()
        {  
           
            date1=new ButtonField("date1");
            date1.setChangeListener(this);
            add(date1);
           
            date2=new ButtonField("date2");
            date2.setChangeListener(this);
            add(date2);
           
            button = new ButtonField("Screen 1 ");
            button.setChangeListener(this);
            add(button);
            lbl=new LabelField();
            add(lbl);
        }
        public void fieldChanged(Field field, int context) {
            if(field==button){//Tue, 27 Mar 2012 09:11:37 GMT
          
                   System.out.println(date1.getLabel().toString()+"   "+date2.getLabel().toString());
                 long startTime = HttpDateParser.parse(date1.getLabel().toString());
                 System.out.println("start time is :" + startTime);
                 long endTime =  HttpDateParser.parse(date2.getLabel().toString());
                 System.out.println("end time is :" + endTime);
                 long diff = endTime - startTime;
          
                 SimpleDateFormat formate=new SimpleDateFormat("HH:mm:ss");
                 String formateddate=formate.formatLocal(diff);
                 System.out.println("Difference in Houres:"+formateddate);
                 lbl.setText("Time Between above dates is :"+formateddate);
            }else if(field==date1)
            {
                date1.setLabel(getDateTimeFromPicker().toString());                                   
           
            }else if(field==date2)
            {
                date2.setLabel(getDateTimeFromPicker().toString());
            }
   
        }
        private String getDateTimeFromPicker()
        {
            picker = DateTimePicker.createInstance( Calendar.getInstance(), "yyyy-MM-dd", "HH:mm:ss");
            picker.doModal();
            cal=picker.getDateTime();
            str="";
            if((cal.get(Calendar.MONTH)+1)<10)
                str=str+cal.get(Calendar.YEAR)+"-"+"0"+(cal.get(Calendar.MONTH)+1);
            else
                str=str+cal.get(Calendar.YEAR)+"-"+(cal.get(Calendar.MONTH)+1);
           
            if(cal.get(Calendar.DATE)<10)
                str=str+"-"+"0"+cal.get(Calendar.DATE);
            else
                str=str+"-"+cal.get(Calendar.DATE);
           
            if(cal.get(Calendar.HOUR_OF_DAY)<10)
                str=str+" "+"0"+cal.get(Calendar.HOUR_OF_DAY);
            else
                str=str+" "+cal.get(Calendar.HOUR_OF_DAY);
           
            if(cal.get(Calendar.MINUTE)<10)
                str=str+":"+"0"+cal.get(Calendar.MINUTE);
            else
                str=str+":"+cal.get(Calendar.MINUTE);
           
            if(cal.get(Calendar.SECOND)<10)
                str=str+":"+"0"+cal.get(Calendar.SECOND);
            else
                str=str+":"+cal.get(Calendar.SECOND);
            return str;
        }
    }

you can see as following output in your screen
![enter image description here][1]


  [1]: http://i.stack.imgur.com/4Rggl.png