- (void)drawRect:(CGRect)rect
{
    UIImage *image2=[UIImage imageNamed:@"me"];
    [image2 drawAtPoint:CGPointMake(100, 100)];
}

- (void)drawRect:(CGRect)rect
{
    //畫圓，以便以后指定可以顯示圖片的范圍
    //獲取圖形上下文
    CGContextRef ctx=UIGraphicsGetCurrentContext();
    CGContextAddEllipseInRect(ctx, CGRectMake(100, 100, 50, 50));
   
    //指定上下文中可以顯示內容的范圍就是圓的范圍
    CGContextClip(ctx);
    UIImage *image2=[UIImage imageNamed:@"me"];
    [image2 drawAtPoint:CGPointMake(100, 100)];
}

- (void)drawRect:(CGRect)rect
{

    //畫三角形，以便以后指定可以顯示圖片的范圍
    //獲取圖形上下文
    CGContextRef ctx=UIGraphicsGetCurrentContext();
//    CGContextAddEllipseInRect(ctx, CGRectMake(100, 100, 50, 50));
    CGContextMoveToPoint(ctx, 100, 100);
    CGContextAddLineToPoint(ctx, 60, 150);
     CGContextAddLineToPoint(ctx, 140, 150);
    CGContextClosePath(ctx);
   
   
    //注意：指定范圍（也就是指定剪切的方法一定要在繪制范圍之前進行調用）
    //指定上下文中可以顯示內容的范圍就是圓的范圍
    CGContextClip(ctx);
    UIImage *image2=[UIImage imageNamed:@"me"];
    [image2 drawAtPoint:CGPointMake(100, 100)];
}

//
//  YYViewController.m
//  01-截屏
//
//  Created by apple on 14-6-12.
//  Copyright (c) 2014年 itcase. All rights reserved.
//

#import "YYViewController.h"
#import "MBProgressHUD+NJ.h"

@interface YYViewController ()
@property (weak, nonatomic) IBOutlet UIView *contentView;
- (IBAction)BtnClick:(UIButton *)sender;

@end

@implementation YYViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
}

- (IBAction)BtnClick:(UIButton *)sender {
   
    //延遲兩秒保存
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        //獲取圖形上下文
        //    UIGraphicsBeginImageContext(self.view.frame.size);
        UIGraphicsBeginImageContext(self.contentView.frame.size);
        //將view繪制到圖形上下文中
       
        //    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
        [self.contentView.layer renderInContext:UIGraphicsGetCurrentContext()];
    
       
        //將截屏保存到相冊
        UIImage *newImage=UIGraphicsGetImageFromCurrentImageContext();
       
        UIImageWriteToSavedPhotosAlbum(newImage,self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
    });
}

 - (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo
{
    if (error) {
        [MBProgressHUD showError:@"保存失敗，請檢查是否擁有相關的權限"];
    }else
    {
//        [MBProgressHUD showMessage:@"保存成功！"];
        [MBProgressHUD showSuccess:@"保存成功！"];
    }
}

@end

//3.從上下文中取出繪制好的圖片
     UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    
     NSData *data = UIImagePNGRepresentation(newImage);
    
     NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"abc.png"];
     NSLog(@"%@", path);
     [data writeToFile:path atomically:YES];

- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo
{
    if (error) {
        [MBProgressHUD showError:@"保存失敗，請檢查是否擁有相關的權限"];
    }else
    {
//        [MBProgressHUD showMessage:@"保存成功！"];
        [MBProgressHUD showSuccess:@"保存成功！"];
    }
}