checksum function

#import <CommonCrypto/CommonDigest.h>

- (NSString *)md5StringFromData:(NSData *)data

{

    void *cData = malloc([data length]);

    unsigned char resultCString[16];

    [data getBytes:cData length:[data length]];

    

    CC_MD5(cData, [data length], resultCString);

    free(cData);

    

    NSString *result = [NSString stringWithFormat:

                        @"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X",

                        resultCString[0], resultCString[1], resultCString[2], resultCString[3], 

                        resultCString[4], resultCString[5], resultCString[6], resultCString[7],

                        resultCString[8], resultCString[9], resultCString[10], resultCString[11],

                        resultCString[12], resultCString[13], resultCString[14], resultCString[15]

                        ];

    return result;

}

reference from :http://stackoverflow.com/questions/1028742/compute-a-checksum-on-the-iphone-from-nsdata

Detect the version of app

NSString* version = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleVersion"];

get rgb data from UIImage

xxx.h

typedef unsigned char byte;

typedef struct RGBPixel    

{

    byte    red;

    byte    green;

    byte    blue;

}   RGBPixel;

typedef struct RGBAPixel    

{

    byte    red;

    byte    green;

    byte    blue;

    byte    alpha;    

}   RGBAPixel;

@interface UIImage(XXX)

- (RGBPixel*)bitmapFromBMP;

- (RGBAPixel*)bitmapFromPNG;

@end

xxx.m

#define RGBA                4

#define RGBA_8_BIT          8

@implementation UIImage(XXX)

- (RGBPixel*)bitmapFromBMP

{

    CFDataRef bitmapData = CGDataProviderCopyData(CGImageGetDataProvider(self.CGImage)); 

    UInt8* pixelByteData = malloc(CFDataGetLength(bitmapData));

    if (!pixelByteData)

        return nil;

    

    CFDataGetBytes(bitmapData, CFRangeMake(0, CFDataGetLength(bitmapData)), pixelByteData);

    return (RGBPixel*)pixelByteData;

}

- (RGBAPixel*)bitmapFromPNG

{

    size_t bytesPerRow = self.size.width * RGBA;

    size_t byteCount = bytesPerRow * self.size.height;

    CGContextRef context = 0;

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    UInt8* pixelByteData = malloc(byteCount);

    RGBAPixel* pixelData = nil;

    

    if (!colorSpace) 

    {

        return nil;

    }

    

    if (!pixelByteData)  

    {

        CGColorSpaceRelease( colorSpace );

        return nil;

    }

    context = CGBitmapContextCreate((void*) pixelByteData,

                                    self.size.width,

                                    self.size.height,

                                    RGBA_8_BIT,

                                    bytesPerRow,

                                    colorSpace,

                                    kCGImageAlphaPremultipliedLast);

    

    if (!context)

    {

        free( pixelByteData );

        CGColorSpaceRelease( colorSpace );

        return nil;

    }

    CGRect rect = { { 0 , 0 }, { self.size.width, self.size.height }    };    

    CGContextDrawImage( context, rect, self.CGImage );

    pixelData = (RGBAPixel*) CGBitmapContextGetData(context);

    

    return pixelData;

    

}

@end

在 iPhone 上實現小畫家基本功能

.h

UIImageView *drawImage_;

CGPoint lastPoint_;

.m

-(id) init

{

if( (self=[super init])) {

        drawImage_ = [[[UIImageView alloc]initWithImage:nil]autorelease];

        drawImage_.frame = CGRectMake(0, 50, 320,400);

        [[[CCDirector sharedDirector]openGLView] addSubview:drawImage_];

        self.isTouchEnabled = YES;

}

return self;

}

- (void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{

    UITouch *touch = [touches anyObject];

    lastPoint_ = [touch locationInView:drawImage_];    

}

- (void)ccTouchesMoved:(NSSet *)touches withEvent:(UIEvent *)event

{

    UITouch *touch = [touches anyObject];

    CGPoint currentPoint = [touch locationInView:drawImage_];

    UIGraphicsBeginImageContext(drawImage_.frame.size);

    

    [drawImage_.image drawInRect:CGRectMake(0, 0, drawImage_.frame.size.width, drawImage_.frame.size.height)];

    CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound); 

    CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 5.0);

    CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 1.0,0.0,0.0, 1.0);

    CGContextBeginPath(UIGraphicsGetCurrentContext());

    CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint_.x, lastPoint_.y);

    CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);

    CGContextStrokePath(UIGraphicsGetCurrentContext());

    drawImage_.image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    lastPoint_ = currentPoint;

}

Detect the orientation of iPhone view

step 1: add a notification

    [[NSNotificationCenter defaultCenter] addObserver:self 

                         selector:@selector(receivedRotate:)                                          

                             name:UIDeviceOrientationDidChangeNotification 

                           object:nil];

step 2: remove a notification

    [[NSNotificationCenter defaultCenter] removeObserver:self  

                             name:UIDeviceOrientationDidChangeNotification 

                           object:nil];

step 3: implement "receiveRotate"

- (void)receivedRotate:(NSNotification*)notification

{

    UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;

    if (deviceOrientation == UIDeviceOrientationPortrait)

    {

        ...

    }

}

Transition between portrait and landscape

Portrait View :
WhatsOnLandscapeController *whatsOnLandscape = [[[WhatsOnLandscapeController alloc] initWithNibName:@"WhatsOnLandscape" bundle:nil]autorelease];

[whatsOnLandscape setModalTransitionStyle:UIModalTransitionStyleCrossDissolve];
[self presentModalViewController:whatsOnLandscape animated:YES];

Landscape View :
[Leave Landscape View]
[self dismissModalViewControllerAnimated:YES];

List iPhone Country Code

NSLocale *currentLocale = [NSLocale currentLocale];

NSArray *countryArray = [NSLocale ISOCountryCodes];

for (NSString *key in countryArray)
{
NSLog(@"code : %@\n",key);
NSString *displayNameString = [currentLocale displayNameForKey:NSLocaleCountryCode value:key];
NSLog(@"displayNameString : %@\n",displayNameString);
}


NSLog(@"Country Code is %@", [currentLocale objectForKey:NSLocaleCountryCode]);