源码0301-图片水印－裁剪－截屏－截取－擦除

//  ViewController.m
//  01-图片水印
#import "ViewController.h"

// 在图片的基础绘制一些文字或者Logo,最终生成一张图片
@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIImageView *imageView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    // 加载图片
    UIImage *image = [UIImage imageNamed:@"小黄人"];
    
    // 0.获取上下文，之前的上下文都是在view的drawRect方法中获取（跟View相关联的上下文layer上下文）
    // 目前我们需要绘制图片到新的图片上，因此需要用到位图上下文
    
    // 怎么获取位图上下文,注意位图上下文的获取方式跟layer上下文不一样。位图上下文需要我们手动创建。
    
    // 开启一个位图上下文，注意位图上下文跟view无关联，所以不需要在drawRect.
    // size:位图上下文的尺寸（新图片的尺寸）
    // opaque: 不透明度 YES：不透明 NO:透明，通常我们一般都弄透明的上下文
    // scale:通常不需要缩放上下文，取值为0，表示不缩放
    UIGraphicsBeginImageContextWithOptions(image.size, NO, 0);
    
    
    // 1.获取上下文(位图上下文)
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    
    // 2.描述路径
    CGContextMoveToPoint(ctx, 50, 50);
    
    CGContextAddLineToPoint(ctx, 200, 200);
    
    [[UIColor redColor] set];
    
    // 3.渲染上下文
    CGContextStrokePath(ctx);
    
    
//    UIBezierPath *path =[UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, 300, 300)];
//    
//    [[UIColor redColor] set];
//    [path stroke];
    
    
//    // 1.绘制原生的图片
//    [image drawAtPoint:CGPointZero];
//    
//    // 2.给原生的图片添加文字
//    NSString *str = @"小码哥";
//    
//    // 创建字典属性
//    NSMutableDictionary *dict = [NSMutableDictionary dictionary];
//    dict[NSForegroundColorAttributeName] = [UIColor redColor];
//    dict[NSFontAttributeName] = [UIFont systemFontOfSize:20];
//    
//    [str drawAtPoint:CGPointMake(200, 528) withAttributes:dict];
    
    // 3.生成一张图片给我们,从上下文中获取图片
    UIImage *imageWater = UIGraphicsGetImageFromCurrentImageContext();
    
    // 4.关闭上下文
//    UIGraphicsEndImageContext();
    
    _imageView.image = imageWater;
    
    
    
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

02-图片裁剪

//  ViewController.m
//  02-图片裁剪
#import "ViewController.h"
#import "UIImage+Image.h"
@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIImageView *imageView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    // 图片裁剪：把正方形图片重新生产一张圆形的图片
    
    // 图片裁剪
    
    UIImage *image = [UIImage imageWithClipImage:[UIImage imageNamed:@"阿狸头像"] borderWidth:1 borderColor:[UIColor redColor]];
    
    _imageView.image = image;
}


- (void)clipImage
{
    // 0.加载图片
    UIImage *image = [UIImage imageNamed:@"阿狸头像"];
    
    // 1.开启位图上下文，跟图片尺寸一样大
    UIGraphicsBeginImageContextWithOptions(image.size, NO, 0);
    
    // 2.设置圆形裁剪区域，正切与图片
    // 2.1创建圆形的路径
    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, image.size.width, image.size.height)];
    
    // 2.2把路径设置为裁剪区域
    [path addClip];
    
    // 3.绘制图片
    [image drawAtPoint:CGPointZero];
    
    // 4.从上下文中获取图片
    UIImage *clipImage = UIGraphicsGetImageFromCurrentImageContext();
    
    // 5.关闭上下文
    UIGraphicsEndImageContext();
    
    _imageView.image = clipImage;
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

图片裁切

//  UIImage+Image.h
//  02-图片裁剪
#import <UIKit/UIKit.h>

@interface UIImage (Image)
+ (UIImage *)imageWithClipImage:(UIImage *)image borderWidth:(CGFloat)borderWidth borderColor:(UIColor *)color;
@end
//  UIImage+Image.m
//  02-图片裁剪
#import "UIImage+Image.h"

@implementation UIImage (Image)
+ (UIImage *)imageWithClipImage:(UIImage *)image borderWidth:(CGFloat)borderWidth borderColor:(UIColor *)color
{
    // 图片的宽度和高度
    CGFloat imageWH = image.size.width;
    
    // 设置圆环的宽度
    CGFloat border = borderWidth;
    
    // 圆形的宽度和高度
    CGFloat ovalWH = imageWH + 2 * border;
    
    // 1.开启上下文
    UIGraphicsBeginImageContextWithOptions(CGSizeMake(ovalWH, ovalWH), NO, 0);
    
    // 2.画大圆
    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, ovalWH, ovalWH)];
    
    [color set];
    
    [path fill];
    
    // 3.设置裁剪区域
    UIBezierPath *clipPath = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(border, border, imageWH, imageWH)];
    [clipPath addClip];
    
    // 4.绘制图片
    [image drawAtPoint:CGPointMake(border, border)];
    
    // 5.获取图片
    UIImage *clipImage = UIGraphicsGetImageFromCurrentImageContext();
    
    // 6.关闭上下文
    UIGraphicsEndImageContext();
    
    return clipImage;
    
}

@end

图片截屏

//  ViewController.m
//  03-屏幕截屏
#import "ViewController.h"

#import "UIImage+Image.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    // 生成一张新的图片
    
  UIImage *image =  [UIImage imageWithCaputureView:self.view];
    
    // image转data
    // compressionQuality： 图片质量 1:最高质量
    
     NSData *data = UIImageJPEGRepresentation(image,1);
    
    [data writeToFile:@"/Users/xiaomage/Desktop/view.png" atomically:YES];
    
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end
//  UIImage+Image.h
//  02-图片裁剪
#import <UIKit/UIKit.h>

@interface UIImage (Image)
// 圆形裁剪
+ (UIImage *)imageWithClipImage:(UIImage *)image borderWidth:(CGFloat)borderWidth borderColor:(UIColor *)color;

// 控件截屏
+ (UIImage *)imageWithCaputureView:(UIView *)view;

@end
//  UIImage+Image.m
//  02-图片裁剪
#import "UIImage+Image.h"

@implementation UIImage (Image)
+ (UIImage *)imageWithClipImage:(UIImage *)image borderWidth:(CGFloat)borderWidth borderColor:(UIColor *)color
{
    // 图片的宽度和高度
    CGFloat imageWH = image.size.width;
    
    // 设置圆环的宽度
    CGFloat border = borderWidth;
    
    // 圆形的宽度和高度
    CGFloat ovalWH = imageWH + 2 * border;
    
    // 1.开启上下文
    UIGraphicsBeginImageContextWithOptions(CGSizeMake(ovalWH, ovalWH), NO, 0);
    
    // 2.画大圆
    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, ovalWH, ovalWH)];
    
    [color set];
    
    [path fill];
    
    // 3.设置裁剪区域
    UIBezierPath *clipPath = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(border, border, imageWH, imageWH)];
    [clipPath addClip];
    
    // 4.绘制图片
    [image drawAtPoint:CGPointMake(border, border)];
    
    // 5.获取图片
    UIImage *clipImage = UIGraphicsGetImageFromCurrentImageContext();
    
    // 6.关闭上下文
    UIGraphicsEndImageContext();
    
    return clipImage;
    
}


+ (UIImage *)imageWithCaputureView:(UIView *)view
{
    // 开启位图上下文
    UIGraphicsBeginImageContextWithOptions(view.bounds.size, NO, 0);
    
    // 获取上下文
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    
    // 把控件上的图层渲染到上下文,layer只能渲染
    [view.layer renderInContext:ctx];
    
    // 生成一张图片
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    
    // 关闭上下文
    UIGraphicsEndImageContext();
    
    return image;
}

@end

04-图片截取

//  ViewController.m
//  04-图片截取
#import "ViewController.h"

@interface ViewController ()

@property (nonatomic, assign) CGPoint startP;

@property (weak, nonatomic) IBOutlet UIImageView *imageV;
@property (nonatomic, weak) UIView *clipView;

@end

@implementation ViewController

- (UIView *)clipView{
    if (_clipView == nil) {
        UIView *view = [[UIView alloc] init];
        _clipView = view;
        
        view.backgroundColor = [UIColor blackColor];
        view.alpha = 0.5;
        
        [self.view addSubview:view];
    }
    
    return _clipView;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    // 给控制器的view添加一个pan手势
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];
    
    [self.view addGestureRecognizer:pan];
}

- (void)pan:(UIPanGestureRecognizer *)pan
{
    CGPoint endA = CGPointZero;
    
    if (pan.state == UIGestureRecognizerStateBegan) { // 一开始拖动的时候
        
        // 获取一开始触摸点
      _startP = [pan locationInView:self.view];
        
    }else if(pan.state == UIGestureRecognizerStateChanged){ // 一直拖动
        // 获取结束点
         endA = [pan locationInView:self.view];
        
        CGFloat w = endA.x - _startP.x;
        CGFloat h = endA.y - _startP.y;
        
        // 获取截取范围
        CGRect clipRect = CGRectMake(_startP.x, _startP.y, w, h);

        
        // 生成截屏的view
        self.clipView.frame = clipRect;
        
        
        
    }else if (pan.state == UIGestureRecognizerStateEnded){
        
        
        // 图片裁剪，生成一张新的图片
        
        // 开启上下文
        // 如果不透明，默认超出裁剪区域会变成黑色，通常都是透明
        UIGraphicsBeginImageContextWithOptions(_imageV.bounds.size, NO, 0);
        
        // 设置裁剪区域
       UIBezierPath *path =  [UIBezierPath bezierPathWithRect:_clipView.frame];
        
        [path addClip];
        
        // 获取上下文
        CGContextRef ctx = UIGraphicsGetCurrentContext();
        
        // 把控件上的内容渲染到上下文
        [_imageV.layer renderInContext:ctx];
        
        
        // 生成一张新的图片
        _imageV.image = UIGraphicsGetImageFromCurrentImageContext();
        
        
        // 关闭上下文
        UIGraphicsEndImageContext();
        
        
        // 先移除
        [_clipView removeFromSuperview];
        // 截取的view设置为nil
        _clipView = nil;
        
    }
    

    // 获取手指的偏移量
//    pan translationInView:<#(UIView *)#>
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

05-图片擦除

//
//  ViewController.m
//  05-图片擦除
#import "ViewController.h"

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIImageView *imageView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];
    
    [self.view addGestureRecognizer:pan];
}


- (void)pan:(UIPanGestureRecognizer *)pan
{
    // 获取当前点
    CGPoint curP = [pan locationInView:self.view];
    
    // 获取擦除的矩形范围
    CGFloat wh = 100;
    CGFloat x = curP.x - wh * 0.5;
    CGFloat y = curP.y - wh * 0.5;
    
    CGRect rect = CGRectMake(x, y, wh, wh);
    
    // 开启上下文
    UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, NO, 0);
    
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    
    // 控件的layer渲染上去
    [_imageView.layer renderInContext:ctx];
    
    // 擦除图片
    CGContextClearRect(ctx, rect);
    
    // 生成一张图片
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    
    _imageView.image = image;
    
    // 关闭上下文
    UIGraphicsEndImageContext();
    
    
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end
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原文地址：https://www.cnblogs.com/laugh/p/6677594.html