iPhone 开发中如何将制作图片放大缩小代码实现案例

原文摘自：http://mobile.51cto.com/iphone-285108.htm

iPhone开发中如何将制作图片放大缩小案例是本文要介绍的内容，主要是来学习iphone开发中动画的制作，具体内容一起来看本文详解。在IPhone SDK开发范例大全中,有很多的范例码。

下面这段范例码,示范了两张图片的交换,以及放大缩小的动画

动画效果请参照下图

#import <UIKit/UIKit.h>

#define IMAGE_VIEW_1    100
#define    IMAGE_VIEW_2    101

#define BIGRECT CGRectMake(0.0f, 0.0f, 320.0f, 435.0f)
#define SMALLRECT CGRectMake(130.0f, 187.0f, 60.0f, 60.0f)

@interface ToggleView: UIView
{
BOOL isOne;
}
@end

@implementation ToggleView

- (id) initWithFrame: (CGRect) aFrame;
{
self = [super initWithFrame:aFrame];

// Load both views, make them non-interactive
UIImageView *imgView1 = [[UIImageView alloc] initWithFrame:BIGRECT];
imgView1.image = [UIImage imageNamed:@"one.png"];
imgView1.userInteractionEnabled = NO;
imgView1.tag = IMAGE_VIEW_1;

UIImageView *imgView2 = [[UIImageView alloc] initWithFrame:SMALLRECT];
imgView2.image = [UIImage imageNamed:@"two.png"];
imgView2.userInteractionEnabled = NO;
imgView2.tag = IMAGE_VIEW_2;

// image 1 is in front of image 2 to begin
[self addSubview:imgView2];
[self addSubview:imgView1];
isOne = YES;

[imgView1 release];
[imgView2 release];

return self;
}

- (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event
{
// Determine which view occupies which role
UIImageView *big = (UIImageView *)[self viewWithTag: (isOne ? IMAGE_VIEW_1 : IMAGE_VIEW_2)];
UIImageView *little = (UIImageView *)[self viewWithTag: (isOne ? IMAGE_VIEW_2 : IMAGE_VIEW_1)];
isOne = !isOne;

// Pack all the changes into the animation block
CGContextRef context = UIGraphicsGetCurrentContext();
[UIView beginAnimations:nil context:context];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
[UIView setAnimationDuration:1.0];

[big setFrame:SMALLRECT];
[big setAlpha:0.5];
[little setFrame:BIGRECT];
[little setAlpha:1.0];

[UIView commitAnimations];

// Hide the shrunken "big" image.
[big setAlpha:0.0f];
[[big superview] bringSubviewToFront:big];
}
@end

@interface HelloController : UIViewController
@end

@implementation HelloController
- (void)loadView
{
ToggleView *contentView = [[ToggleView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
contentView.backgroundColor = [UIColor whiteColor];
self.view = contentView;
[contentView release];
}
@end

@interface SampleAppDelegate : NSObject <UIApplicationDelegate>
@end

@implementation SampleAppDelegate
- (void)applicationDidFinishLaunching:(UIApplication *)application {
UIWindow *window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
HelloController *hello = [[HelloController alloc] init];
[window addSubview:hello.view];
[window makeKeyAndVisible];
}
@end

int main(int argc, char *argv[])
{
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
int retVal = UIApplicationMain(argc, argv, nil, @"SampleAppDelegate");
[pool release];
return retVal;
}
#import <UIKit/UIKit.h>

#define IMAGE_VIEW_1    100
#define    IMAGE_VIEW_2    101

#define BIGRECT CGRectMake(0.0f, 0.0f, 320.0f, 435.0f)
#define SMALLRECT CGRectMake(130.0f, 187.0f, 60.0f, 60.0f)

@interface ToggleView: UIView
{
BOOL isOne;
}
@end

@implementation ToggleView

- (id) initWithFrame: (CGRect) aFrame;
{
self = [super initWithFrame:aFrame];

// Load both views, make them non-interactive
UIImageView *imgView1 = [[UIImageView alloc] initWithFrame:BIGRECT];
imgView1.image = [UIImage imageNamed:@"one.png"];
imgView1.userInteractionEnabled = NO;
imgView1.tag = IMAGE_VIEW_1;

UIImageView *imgView2 = [[UIImageView alloc] initWithFrame:SMALLRECT];
imgView2.image = [UIImage imageNamed:@"two.png"];
imgView2.userInteractionEnabled = NO;
imgView2.tag = IMAGE_VIEW_2;

// image 1 is in front of image 2 to begin
[self addSubview:imgView2];
[self addSubview:imgView1];
isOne = YES;

[imgView1 release];
[imgView2 release];

return self;
}

- (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event
{
// Determine which view occupies which role
UIImageView *big = (UIImageView *)[self viewWithTag: (isOne ? IMAGE_VIEW_1 : IMAGE_VIEW_2)];
UIImageView *little = (UIImageView *)[self viewWithTag: (isOne ? IMAGE_VIEW_2 : IMAGE_VIEW_1)];
isOne = !isOne;

// Pack all the changes into the animation block
CGContextRef context = UIGraphicsGetCurrentContext();
[UIView beginAnimations:nil context:context];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
[UIView setAnimationDuration:1.0];
[big setFrame:SMALLRECT];
[big setAlpha:0.5];
[little setFrame:BIGRECT];
[little setAlpha:1.0];
[UIView commitAnimations];
// Hide the shrunken "big" image.
[big setAlpha:0.0f];
[[big superview] bringSubviewToFront:big];
}
@end
@interface HelloController : UIViewController
@end
@implementation HelloController
- (void)loadView
{
ToggleView *contentView = [[ToggleView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
contentView.backgroundColor = [UIColor whiteColor];
self.view = contentView;
[contentView release];
}
@end
@interface SampleAppDelegate : NSObject <UIApplicationDelegate>
@end
@implementation SampleAppDelegate
- (void)applicationDidFinishLaunching:(UIApplication *)application {
UIWindow *window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
HelloController *hello = [[HelloController alloc] init];
[window addSubview:hello.view];
[window makeKeyAndVisible];
}
@end
int main(int argc, char *argv[])
{
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
int retVal = UIApplicationMain(argc, argv, nil, @"SampleAppDelegate");
[pool release];
return retVal;
}

最重要的动画代码

- (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event
{
// 這一段代碼,設定目前哪一張圖是大圖,哪一張是小圖
UIImageView *big = (UIImageView *)[self viewWithTag: (isOne ? IMAGE_VIEW_1 : IMAGE_VIEW_2)];
UIImageView *little = (UIImageView *)[self viewWithTag: (isOne ? IMAGE_VIEW_2 : IMAGE_VIEW_1)];
isOne = !isOne;

// 這是使用動畫的一些基本設定
CGContextRef context = UIGraphicsGetCurrentContext();
[UIView beginAnimations:nil context:context];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut]; // 設定為IN OUT的動畫
[UIView setAnimationDuration:1.0]; // 動畫時間為一秒

[big setFrame:SMALLRECT];
[big setAlpha:0.5];
[little setFrame:BIGRECT];
[little setAlpha:1.0];

[UIView commitAnimations];

// Hide the shrunken "big" image.
[big setAlpha:0.0f];
[[big superview] bringSubviewToFront:big];
}
@end
- (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event
{
// 這一段代碼,設定目前哪一張圖是大圖,哪一張是小圖
UIImageView *big = (UIImageView *)[self viewWithTag: (isOne ? IMAGE_VIEW_1 : IMAGE_VIEW_2)];
UIImageView *little = (UIImageView *)[self viewWithTag: (isOne ? IMAGE_VIEW_2 : IMAGE_VIEW_1)];
isOne = !isOne;

// 這是使用動畫的一些基本設定
CGContextRef context = UIGraphicsGetCurrentContext();
[UIView beginAnimations:nil context:context];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut]; // 設定為IN OUT的動畫
[UIView setAnimationDuration:1.0]; // 動畫時間為一秒

[big setFrame:SMALLRECT];
[big setAlpha:0.5];
[little setFrame:BIGRECT];
[little setAlpha:1.0];

[UIView commitAnimations];

// Hide the shrunken "big" image.
[big setAlpha:0.0f];
[[big superview] bringSubviewToFront:big];
}
@end