图片转场效果

UniversalTransTestViewController.h

#import <UIKit/UIKit.h>
#import "ImageProcess.h"

#define KFrame	20

@class ImageProcess;
@interface UniversalTransTestViewController : UIViewController {
	UIImage *fromImage;
	UIImage *toImage;
	UIImage *ruleImage;
	UIImage *DestImage;
	UIImageView *drawImageView;
	
	ImageProcess *imgS1Proc;
	ImageProcess *imgS2Proc;
	ImageProcess *imgRuleProc;
	ImageProcess *imgDestProc;
	
	NSCondition	*timerCondition;
	unsigned char *pixelDataS1;			
	unsigned char *pixelDataS2;
	unsigned char *pixelDataRule;
	unsigned char *pixelDataDest;
	int	pixelPosition[480][320];
	int	bank[480][320];
	BOOL isRunning;
	
	NSTimer *timer;
	float countTime;
	int lim;
}

- (void)initImageView:(UIImage *)image;
- (void)setTransAtLayer:(int)index method:(NSString *)method time:(int)time rule:(NSString *)ruleImageName;
- (void)processImage;
@end

UniversalTransTestViewController.m

#import "UniversalTransTestViewController.h"

@implementation UniversalTransTestViewController

- (void)viewDidLoad {
	fromImage = [UIImage imageNamed:@"Car2.jpg"];
	toImage = [UIImage imageNamed:@"Car1.jpg"];
	DestImage = nil;
	isRunning = YES;
	timerCondition = [[NSCondition alloc]init];
	[self initImageView:fromImage];
	[self setTransAtLayer:0 method:@"universal" time:2000 rule:@"r2.png"];
}

- (void)initImageView:(UIImage *)image {
	drawImageView = [[UIImageView alloc] initWithImage:fromImage];
	drawImageView.frame = CGRectMake((self.view.bounds.size.width - fromImage.size.width) / 2,
									 (self.view.bounds.size.height - fromImage.size.height) / 2,
									 fromImage.size.width, fromImage.size.height);
	CGAffineTransform rotate = CGAffineTransformMakeRotation(-1.57);
	drawImageView.transform = rotate;
	[self.view addSubview:drawImageView];
	[drawImageView release];
}

- (void)setTransAtLayer:(int)index method:(NSString *)method time:(int)time rule:(NSString *)ruleImageName {
	if([method isEqualToString:@"universal"]) {
		ruleImage = [UIImage imageNamed:ruleImageName];
		countTime = 0;
		lim = 0;
		imgS1Proc = [[ImageProcess alloc] initWithImage:fromImage];
		imgS2Proc = [[ImageProcess alloc] initWithImage:toImage];
		imgRuleProc = [[ImageProcess alloc] initWithImage:ruleImage];
		imgDestProc = [[ImageProcess alloc] initWithImage:fromImage];
		pixelDataS1 = [imgS1Proc GetBegin];
		pixelDataS2 = [imgS2Proc GetBegin];
		pixelDataRule = [imgRuleProc GetBegin];
		pixelDataDest = [imgDestProc GetBegin];
		
		for (int i = 0; i < 480; i++)
			for (int j = 0; j < 320; j++) {
                pixelPosition[i][j] = (j * 480 + i) << 2;
                bank[i][j] = 0;
			}
		[NSThread detachNewThreadSelector:@selector(transImage) toTarget:self withObject:nil];
		timer = [NSTimer scheduledTimerWithTimeInterval:0.05 target:self selector:@selector(TimerClock:) userInfo:nil repeats:YES];
		[timer fire];
	}
}

- (void)TimerClock:(id)sender {
	[timerCondition broadcast];
}

- (void)transImage {
    isRunning = YES;
	while (countTime < 2300) {
		[timerCondition wait];
		lim += 255 / (2 * KFrame);
		[self processImage];
		countTime += 1000 / KFrame;
	}
	[timer invalidate];
	isRunning = NO;
}

- (void)processImage {
	NSLog(@"begin");
	
	for (int i = 0; i < 480; i++) {
		for (int j = 0; j < 320; j++) {
			if(bank[i][j] < 1) {
				int count = pixelPosition[i][j];
				if(pixelDataRule[count] < lim) {
					pixelDataDest[count] = pixelDataS2[count];
					pixelDataDest[count + 1] = pixelDataS2[count + 1];
					pixelDataDest[count + 2] = pixelDataS2[count + 2];
					bank[i][j]++;
				}
			}
		}
	}
    NSLog(@"end");
	if(DestImage != nil)
		[DestImage release];
	DestImage = [imgDestProc getImage];
	[self performSelectorOnMainThread:@selector(ChangeImage) withObject:nil waitUntilDone:NO];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
	static int num = 0;
	if(isRunning == NO) {
		countTime = 0;
		lim = 0;
		[imgDestProc release];
		imgDestProc = [[ImageProcess alloc] initWithImage:fromImage];
		for (int i = 0; i < 480; i++)
			for (int j = 0; j < 320; j++) {
				bank[i][j] = 0;
			}
		[imgRuleProc release];
		
		switch (num) {
			case 0:
				imgRuleProc = [[ImageProcess alloc] initWithImage:[UIImage imageNamed:@"r1.png"]];
				break;
			case 1:
				imgRuleProc = [[ImageProcess alloc] initWithImage:[UIImage imageNamed:@"r2.png"]];
				break;
			case 2:
				imgRuleProc = [[ImageProcess alloc] initWithImage:[UIImage imageNamed:@"r3.png"]];
				break;
			case 3:
				imgRuleProc = [[ImageProcess alloc] initWithImage:[UIImage imageNamed:@"r5.png"]];
				break;
			default:
				imgRuleProc = [[ImageProcess alloc] initWithImage:[UIImage imageNamed:@"r5.png"]];
				break;
		}
		num++;
		if(num > 3)
			num = 0;
		pixelDataRule = [imgRuleProc GetBegin];
		pixelDataDest = [imgDestProc GetBegin];
		[NSThread detachNewThreadSelector:@selector(transImage) toTarget:self withObject:nil];
		timer = [NSTimer scheduledTimerWithTimeInterval:0.05 target:self selector:@selector(TimerClock:) userInfo:nil repeats:YES];
	}
}

- (void)ChangeImage {
	[drawImageView setImage:DestImage];
}

- (void)dealloc {
	[imgS1Proc release];
	[imgS2Proc release];
	[imgRuleProc release];
	[imgDestProc release];
    [super dealloc];
}

@end

ImageProcess.h

#import <Foundation/Foundation.h>

@interface ImageProcess : NSObject {
	CGContextRef context;			// bitmap context
	unsigned char *pixelData;		// bitmap data pointer
	int width, height;				// bitmap width and height
}

- (id) initWithImage: (UIImage *) image;		// initialize and load image
- (unsigned char *)colorAtX:(int)x y:(int)y;	// get pixel color
- (unsigned char *)GetBegin;
- (UIImage *)getImage;							// get image
- (void)dealloc;								// dealloc
@end

ImageProcess.m

#import "ImageProcess.h"

@implementation ImageProcess

// create BitmapContext with UIImage and use 'pixelData' as the data pointer
- (id) initWithImage: (UIImage *) image {
	self = [super init];
	
	if(!self) {
		return nil;
	}
    
	CGColorSpaceRef colorSpace;
	int             bitmapByteCount;
	int             bitmapBytesPerRow;
	
	// bitmap settings
	context = NULL;
	width	= image.size.width;
	height	= image.size.height;
	bitmapBytesPerRow = (width * 4);
	bitmapByteCount = (bitmapBytesPerRow * height);
	
	// create color space
	colorSpace = CGColorSpaceCreateDeviceRGB();
	
	// create data pointer
	free(pixelData);
	pixelData = malloc(bitmapByteCount);
	
	// create bitmap context
	CGContextRelease(context);
	context = CGBitmapContextCreate (pixelData, width, height, 8, bitmapBytesPerRow,
									 colorSpace, kCGImageAlphaPremultipliedLast);
	CGColorSpaceRelease(colorSpace);
	
	// draw image data to context
	CGContextDrawImage(context, CGRectMake(0, 0, width, height), image.CGImage);
	pixelData = CGBitmapContextGetData(context);
	
	return self;
}

- (unsigned char *)colorAtX:(int)x y:(int)y {
	return & (pixelData[(y * width + x) << 2]);
}

- (unsigned char *)GetBegin {
	return pixelData;
}

- (UIImage *)getImage {
	CGImageRef cgImg = CGBitmapContextCreateImage(context);
	UIImage *localImg = [[[UIImage alloc] initWithCGImage:cgImg] autorelease];
	CGImageRelease(cgImg);
	return localImg;
}

- (void)dealloc {
	[super dealloc];
	free(pixelData);
	CGContextRelease(context);
}

@end

示例图：