iOS实现图片的缩放和居中显示
直接上代码 // //MoveScaleImageController.h //MoveScaleImage // //Created byon 12-4-24. //Copyright (c) 2012年__MyCompanyName__. All rights reserved. // #import <UIKit/UIKit.h> #import "MoveScaleImageView.h" @interface MoveScaleImageController: UIViewController<UIScrollViewDelegate>{ UIScrollView *myScrollView; UIImageView *myImageView; } @property(retain,nonatomic)UIScrollView *myScrollView; @property(retain,nonatomic)UIImageView *myImageView; @end // //MoveScaleImageController.m //MoveScaleImage // //Created byon 12-4-24. //Copyright (c) 2012年__MyCompanyName__. All rights reserved. // #import "MoveScaleImageController.h" @interface MoveScaleImageController() @end @implementation MoveScaleImageController @synthesize myScrollView; @synthesize myImageView; -(void)dealloc{ [myScrollView release]; [myImageView release]; [super dealloc]; } -(void)loadView{ [super loadView]; self.view.backgroundColor = [UIColor lightGrayColor]; //UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect]; UIButton *btn = [[UIButton alloc]initWithFrame:CGRectMake(110, 200, 100, 50)]; //[btn setFrame:CGRectMake(110, 200, 100, 40)]; [btn setBackgroundColor:[UIColor whiteColor]]; [btn setTitle:@"点击查看图片" forState:UIControlStateNormal]; [btn.titleLabel setFont:[UIFont systemFontOfSize:13]]; [btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal]; [btn addTarget:self action:@selector(clickEvent:) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:btn]; [btn release]; //下面是我要剪切区域的覆盖层 //if(self.centerOverLayView==nil) //{ //UIView *centerView=[[UIView alloc] initWithFrame:CGRectMake(20, 100, 280, 210)]; //self.centerOverLayView=centerView; //[centerView release]; //} //self.centerOverLayView.backgroundColor=[UIColor clearColor]; //self.centerOverLayView.layer.borderColor=[UIColor orangeColor].CGColor; //self.centerOverLayView.layer.borderWidth=2.0; //[self.view addSubview:self.centerOverLayView]; } -(void)clickEvent:(id)sender{ NSLog(@"***********clickeventad"); myScrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)]; if(self.myScrollView==nil) { UIScrollView *scrollView=[[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)]; self.myScrollView=scrollView; [scrollView release]; } self.myScrollView.backgroundColor=[UIColor blueColor]; self.myScrollView.delegate=self; self.myScrollView.multipleTouchEnabled=YES; self.myScrollView.minimumZoomScale=1.0; self.myScrollView.maximumZoomScale=10.0; [self.view addSubview:self.myScrollView]; UIImage *_image = [UIImage imageNamed:@"image.jpg"]; CGFloat imageView_X = (_image.size.width > self.view.frame.size.width) ? self.view.frame.size.width : _image.size.width; CGFloat imageView_Y; CGFloat origin; if(_image.size.width > self.view.frame.size.width){ origin = self.view.frame.size.width/_image.size.width; imageView_Y = _image.size.height*origin; } myImageView = [[UIImageView alloc]initWithFrame:CGRectMake((self.view.frame.size.width-imageView_X)/2, (self.view.frame.size.height-imageView_Y)/2, imageView_X, imageView_Y)]; if(self.myImageView==nil) { UIImageView *imageView=[[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)]; self.myImageView=imageView; [imageView release]; } //[myImageView setImage:_image]; UIImage *originImage=[[UIImage alloc]initWithCGImage:_image.CGImage]; [myImageView setImage:originImage]; //[myImageView setFrame:CGRectMake(0, 0, _image.size.width, _image.size.height)]; [self.myScrollView addSubview:self.myImageView]; UIButton *closeBtn = [[UIButton alloc]initWithFrame:CGRectMake(10, 10, 50, 50)]; [closeBtn setBackgroundColor:[UIColor redColor]]; [closeBtn setAlpha:0.5]; [closeBtn addTarget:self action:@selector(closeEvent:) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:closeBtn]; [closeBtn release]; //UIView *backView = [[UIView alloc] initWithFrame:CGRectInset(self.view.frame, 5, 5)]; //backView.alpha = 0.5; //backView.backgroundColor = [UIColor blackColor]; ////[self.view addSubview:backView]; // //UIImage* image=[UIImage imageNamed:@"image.jpg"]; //MoveScaleImageView*fileContent = [[MoveScaleImageView alloc]initWithFrame:CGRectMake(0, 44, 320, 436)]; //[fileContent setImage:image]; // ////[backView addSubview:fileContent]; //[self.view addSubview:fileContent]; // //[backView release]; //[fileContent release]; } -(void)closeEvent:(id)sender{ [self.myImageView setHidden:YES]; [self.myScrollView setHidden:YES]; } #pragma mark UIScrollView delegate methods //实现图片的缩放 -(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{ NSLog(@"**************viewForZoomingInScrollView"); return self.myImageView; } //实现图片在缩放过程中居中 - (void)scrollViewDidZoom:(UIScrollView *)scrollView { CGFloat offsetX = (scrollView.bounds.size.width > scrollView.contentSize.width)?(scrollView.bounds.size.width - scrollView.contentSize.width)/2 : 0.0; CGFloat offsetY = (scrollView.bounds.size.height > scrollView.contentSize.height)?(scrollView.bounds.size.height - scrollView.contentSize.height)/2 : 0.0; self.myImageView.center = CGPointMake(scrollView.contentSize.width/2 + offsetX,scrollView.contentSize.height/2 + offsetY); } - (void)viewDidLoad { [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); } @end 本文转自 卓行天下 51CTO博客，原文链接：http://blog.51cto.com/9951038/1772523，如需转载请自行联系原作者
