（IOS）截图Demo-白红宇

（IOS）截图Demo

阅读量：5127 次

发布时间：2019-06-13

本文共 3029 字，大约阅读时间需要 10 分钟。

思路是建一个UIView的子类，获取划动出的矩形，用协议将矩形传递给代理对象，依据该矩形完成图像数据的截取，并显示出来。

截图视图类：

#import 
     
      @protocol UICutImgDelegate;@interface BIDCutView : UIView{    CGPoint startPoint;    CGRect targetRect;        id 
      
        _delegate;}@property (assign , nonatomic) id delegate;@end@protocol UICutImgDelegate 
       
        -(void)cutImgWithRect:(CGRect) aRect;-(void)clear;@end

#import "BIDCutView.h"@implementation BIDCutView@synthesize delegate=_delegate;- (id)initWithFrame:(CGRect)frame{    self = [super initWithFrame:frame];    if (self) {        // Initialization code    }    return self;}- (void)drawRect:(CGRect)rect{    CGContextRef ctx = UIGraphicsGetCurrentContext();    CGContextSetLineWidth(ctx, 1.5);    CGContextSetStrokeColorWithColor(ctx, [UIColor purpleColor].CGColor);    CGFloat lengths[2] = {
   15.0,5.0};    CGContextSetLineDash(ctx, 2, lengths, 2);    CGContextStrokeRect(ctx, targetRect);  //画虚线矩形}-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{    [self.delegate clear];    startPoint=[[touches anyObject] locationInView:self];}-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{    CGPoint currentPoint=[[touches anyObject] locationInView:self];    targetRect = CGRectMake(startPoint.x, startPoint.y, currentPoint.x-startPoint.x, currentPoint.y-startPoint.y);    [self setNeedsDisplay];}-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{    if (self.delegate && [self.delegate respondsToSelector:@selector(cutImgWithRect:)]) {        [self.delegate cutImgWithRect:targetRect];    }} @end

视图控制器：（作为截图视图的代理对象）

#import 
     
      #import "BIDCutView.h"@interface BIDRootViewController : UIViewController 
      
       @end

#import "BIDRootViewController.h"#import "BIDSimpleTouchFun.h"#import "BIDDiscount.h"@implementation BIDRootViewController-(void)loadView{    [super loadView]; 　　//self.view=[[[BIDDrawViewalloc] initWithFrame:CGRectMake(0, 0, 320, 460)] autorelease];

BIDCutView *cutView=[[BIDCutView alloc] initWithFrame:CGRectMake(0, 0, 320, 460)];    cutView.backgroundColor=[UIColor colorWithPatternImage:[UIImage imageNamed:@"abc.jpg"]];    cutView.delegate = self;    [self.view addSubview:cutView];    [cutView release];}- (void)viewDidLoad{    [super viewDidLoad];}- (void)didReceiveMemoryWarning{    [super didReceiveMemoryWarning];}-(void)cutImgWithRect:(CGRect)aRect{    UIImage *img=[UIImage imageNamed:@"abc.jpg"];    CGImageRef imgRef = img.CGImage;    CGImageRef targetImgRef = CGImageCreateWithImageInRect(imgRef, aRect);  //图像的截取    UIImage *targetImg=[UIImage imageWithCGImage:targetImgRef];        UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, aRect.size.width, aRect.size.height)];    imgView.image = targetImg; //把截取得的图像显示到视图中去    imgView.tag=1000;    [self.view addSubview:imgView];    [imgView release];}-(void)clear{    UIImageView *imgView=(UIImageView *)[self.view viewWithTag:1000];    [imgView removeFromSuperview];}

效果：