手势、画图、截图

实现的效果如图：

首先要导入的是QuartzCore.framework框架

#import "ViewController.h"

#import "SkipView.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad

{

    [superviewDidLoad];

    SkipView *myView =[[SkipViewalloc]initWithFrame:CGRectMake(0,0,320, 480-20)];    

    [self.viewaddSubview:myView];

}

- (void)didReceiveMemoryWarning

{

    [superdidReceiveMemoryWarning];

}

@end

UIView

#import <UIKit/UIKit.h>

@interface SkipView : UIView

@property (assign,nonatomic)CGPoint aPoint;//始点

@property (assign,nonatomic)CGPoint bPoint;//终点

@property (retain,nonatomic)UIImageView *myImgView;//图形框架

@end

#import "SkipView.h"

#import <QuartzCore/QuartzCore.h>

@implementation SkipView

- (id)initWithFrame:(CGRect)frame

{

    self = [superinitWithFrame:frame];

    if (self) {

        

        self.backgroundColor  = [UIColorcolorWithPatternImage:[UIImageimageNamed:@"che.jpg"]];//设置view的背景图片

        

        self.myImgView = [[UIImageViewalloc]init];//初始化视图框

        

        [self addSubview:self.myImgView];

    

    }

    return self;

}

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

{

    

    UITouch *touch = [touches anyObject];//获取初始触摸对象

    

    self.aPoint = [touchlocationInView:self];//获取触摸在视图上的位置

   NSLog(@"%@",NSStringFromCGPoint(self.aPoint));

}

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

{

    

    UITouch *touch = [touches anyObject];//获取最后的任意位置

    

    self.bPoint = [touchlocationInView:self];//获取触摸在视图上的位置

    

    NSLog(@"%@",NSStringFromCGPoint(self.bPoint));

    

    [selfsetNeedsDisplay];//设置刷新界面

    

    //截取图片方法，截取图片返回给image

    UIImage*image=[selfcaptureView:nil];

    

    //截取的图片大小

    self.myImgView.frame=CGRectMake(self.aPoint.x,self.aPoint.y,self.bPoint.x-self.aPoint.x,self.bPoint.y-self.aPoint.y);

    

    //设置图片视图框的图片为截取的图片

    [self.myImgViewsetImage:image];

    

    [UIViewanimateWithDuration:1animations:^{

        self.myImgView.frame=CGRectMake(0,0, image.size.width, image.size.height);

    }];  

}

// Drawing pictures

- (void)drawRect:(CGRect)rect

{

    

    CGContextRef ref =UIGraphicsGetCurrentContext();//获取上下文对象

    

    CGContextSetLineWidth(ref,2.0f);//设置绘图线框

    

    CGContextSetStrokeColorWithColor(ref, [UIColorredColor].CGColor);//设置线框的颜色

    

    CGFloat a[]={10,10};//给定一个数组

    /*

     *CGContextRef c   上下文

     *CGFloat phase   跳过多少个点

     *const CGFloat *lengths   用数组表示一个矩形间距

     *size_t count    数组大小

     *CGContextSetLineDash(CGContextRef c, CGFloat phase, const CGFloat *lengths, size_t count);

     */

    

    CGContextSetLineDash(ref,5, a,2);//设置虚线的样式

    

    CGContextMoveToPoint(ref,self.aPoint.x,self.aPoint.y);//设置起始点

    

    CGContextAddRect(ref,CGRectMake(self.aPoint.x,self.aPoint.y,self.bPoint.x-self.aPoint.x,self.bPoint.y-self.aPoint.y));//设置矩形框的位置大小

    

    CGContextStrokePath(ref);//开始绘制图形

    

}

//截图片的方法

-(UIImage*)captureView:(UIView *)theView

{

    CGRect rect = self.frame;

    

    UIGraphicsBeginImageContext(rect.size);//获取图形上下文

   

    CGContextRef context =UIGraphicsGetCurrentContext();

    

    [self.layerrenderInContext:context];//这里需导入#import <QuartzCore/QuartzCore.h>还有QuartzCore框架

    

    UIImage *img =UIGraphicsGetImageFromCurrentImageContext();

    

    UIGraphicsEndImageContext();

    

    CGRect rect1 = CGRectMake(self.aPoint.x,self.aPoint.y,self.bPoint.x-self.aPoint.x,self.bPoint.y-self.aPoint.y);//创建矩形框

    UIImage * im = [UIImageimageWithCGImage:CGImageCreateWithImageInRect([imgCGImage], rect1)];

    

    return im;

}

@end