ios 图片的截取

第一种：整个屏幕截取

在ViewController中写的，这个类是一个视图控制器

-(void)loadView{

   //静态方法sharedApplication

    [[UIApplication sharedApplication]setStatusBarHidden:YES //把状态栏隐藏

                                           withAnimation:UIStatusBarAnimationSlide];

    UIImage *mage=[UIImage imageNamed:@"image.png"];

    UIImageView *imageView=[[UIImageView alloc]initWithFrame:[[UIScreen mainScreen]applicationFrame]];

    //UIImageView *im=[UIImageView alloc]initWithImage:mage];

    [imageView setImage:mage];

    

    self.view=[[UIView alloc]initWithFrame:[[UIScreen mainScreen]applicationFrame]];

               [self.view addSubview:contentView];

    CGRect rect=CGRectMake(0, 0, 320, 480);

    UIGraphicsBeginImageContext(rect.size);

    CGContextRef currentContext=UIGraphicsGetCurrentContext();

    CGContextClipToRect(currentContext,rect);

    CGContextDrawImage(currentContext, rect, mage.CGImage);

    UIImage *image=UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    contentView.image=image;

    self.view=[[UIView alloc]initWithFrame:[[UIScreen mainScreen]applicationFrame]];

    [self.view addSubview:contentView];

    [image release];

    

}

第二种：整张图片的缩略

-(void)loadView{

    [[UIApplication sharedApplication]setStatusBarHidden:YES withAnimation:UIStatusBarAnimationSlide];

    UIImage *image=[UIImage imageNamed:@"image.png"];

   //UIImageView *contentView=[[UIImageView alloc]initWithFrame:[[UIScreen mainScreen] applicationFrame]];

    //用来控制图片缩到多大

    CGRect rect=CGRectMake(0, 0, 160, 240);

    UIGraphicsBeginImageContext(rect.size);

    CGContextRef currentContent=UIGraphicsGetCurrentContext();

    CGContextClipToRect(currentContent, rect);

    [image drawInRect:rect];

    UIImage *image=UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    UIImageView *contentView=[[UIImageView alloc]initWithFrame:rect];

    contentView.image=image;

    self.view=[[UIView alloc]initWithFrame:[[UIScreen mainScreen]applicationFrame]];

    [self.view addSubview:contentView];

    

    [image release];

}

第san种：真正的截取图片

- (void)loadView {

   

    [[UIApplication sharedApplication] setStatusBarHidden:YES withAnimation: UIStatusBarAnimationSlide];

    UIImage *image=[UIImage imageNamed:@"image2.png"];

    

    CGRect rect = CGRectMake(33, 22, 140, 353);//创建矩形框

    CGRect re=CGRectMake(0, 0, 140, 140);

    UIImageView *contentView = [[UIImageView alloc] initWithFrame:re];

    contentView.image=[UIImage imageWithCGImage:CGImageCreateWithImageInRect([image CGImage], rect)];

    

    self.view=[[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];

    ImageView *imageView=[[ImageView alloc]initWithFrame:CGRectMake(0, 0, 320, 480)];

    self.view.backgroundColor=[UIColor yellowColor];

    [self.view addSubview:imageView];

    [self.view addSubview:contentView];

    

    [image release];

}

******************************以下是写的一个简单的Demo******************************

#import <UIKit/UIKit.h>

@interface imageView : UIView{

    CGPoint starPoint;

    CGPoint endPoint;

    UIImage *image;

}

@end

#import "imageView.h"

@implementation imageView

-(void)dealloc{

    

    [super dealloc];

}

- (id)initWithFrame:(CGRect)frame

{

    self = [super initWithFrame:frame];

    if (self) {

        allMovePoints=[[NSMutableArray alloc]init];

        //self.frame=CGRectMake(0, 0, 220, 340);

        self.frame=CGRectMake(0, 0, 320, 480);

        image=[UIImage imageNamed:@"image.png"];

        self.backgroundColor=[UIColor colorWithPatternImage:image];

//        UIImageView *imageView=[[UIImageView alloc]initWithImage:image];

//        imageView.tag=3;

//        imageView.frame=CGRectMake(0, 0, 320, 360);

//        [self addSubview:imageView];

        

        // Initialization code

    }

    return self;

}

-(void)drawRect:(CGRect)rect{

    CGContextRef context=UIGraphicsGetCurrentContext();

    CGContextSetRGBStrokeColor(context, 1, 5.0, 1.0, 1.0);

    CGContextSetLineWidth(context, 2.0);

    CGContextAddRect(context, CGRectMake(starPoint.x, starPoint.y, endPoint.x-starPoint.x, endPoint.y-starPoint.y));

    CGContextStrokePath(context);

    

    

}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{

    UITouch *t=[touches anyObject];

    starPoint=[t locationInView:self];

}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{

    UITouch *t=[touches anyObject];

    //CGPoint p=[t locationInView:self];

    endPoint=[t locationInView:self];

    UIImageView *image11=(UIImageView *)[self viewWithTag:3];

    [image11 removeFromSuperview];

    //[allMovePoints addObject:NSStringFromCGPoint(p)];

    [self setNeedsDisplay];

    

}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{

    CGRect rect1 = CGRectMake(starPoint.x, starPoint.y, endPoint.x-starPoint.x, endPoint.y-starPoint.y);//创建矩形框

    CGRect re=CGRectMake(320-endPoint.x+starPoint.x, 480-endPoint.y+starPoint.y, endPoint.x-starPoint.x, endPoint.y-starPoint.y);

    UIImageView *contentView = [[UIImageView alloc] initWithFrame:re];

    contentView.tag=3;

    contentView.image=[UIImage imageWithCGImage:CGImageCreateWithImageInRect([image CGImage], rect1)];

    [self addSubview:contentView];

}

@end