图片的裁剪

Main.storyboard

ViewController.m

//

//  ViewController.m

//  6A01.图片的裁剪（位图上下文）

//

//  Created by huan on 16/1/29.

//  Copyright © 2016年 huanxi. All rights reserved.

//

 

#import "ViewController.h"

 

@interface ViewController ()

@property (weak, nonatomic) IBOutlet UIImageView *imgView;

 

@end

 

@implementation ViewController

 

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

}

 

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

    //需求：从位图上下文，裁剪图片[裁剪成圆形，也添加圆形的边框],生成一张图片

    //获取要裁剪的图片

    UIImage *img = [UIImage imageNamed:@"papa"];

    //1.开启位图上下文

    UIGraphicsBeginImageContextWithOptions(img.size, NO, 0.0);

    CGRect imgRect = CGRectMake(0, 0, img.size.width, img.size.height);

    //1.1 获取当前位图上下文

#warning 在自定义的view的drawRect方法里，调用UIGraphicsGetCurrentContext获取的上下文，是图层上下文（Layeer Graphics Context）

    CGContextRef bitmapContext = UIGraphicsGetCurrentContext();

    //2.往位图上下文剪裁图片

    //2.1 指定一个圆形的路径，把圆形之外的剪切掉

    CGContextAddEllipseInRect(bitmapContext, imgRect);

    CGContextClip(bitmapContext);

    

    //2.2 添加图片

    [img drawInRect:imgRect];

    

    //2.3 添加边框

    //设置边框的宽度

    CGContextSetLineWidth(bitmapContext, 3);

    //设置边框的颜色

    [[UIColor blueColor] set];

    CGContextAddEllipseInRect(bitmapContext, imgRect);

    CGContextStrokePath(bitmapContext);

    //3. 获取当前位图上下文的图片

    UIImage *newImg = UIGraphicsGetImageFromCurrentImageContext();

    //4. 结束位图编辑

    UIGraphicsEndImageContext();

    //把图片显示在控制器的view

    self.imgView.image = newImg;

    

    //保存图片，先把图片转成NSData,然后调用其的write

    NSData *imgData = UIImagePNGRepresentation(newImg);

    [imgData writeToFile:@"/Users/huan/Desktop/new.png" atomically:YES];

 

}

 

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

 

@end