ios 图片水印 图片裁剪和屏幕截图

1.创建个UIImageView
@property (weak, nonatomic) IBOutlet UIImageView *neImage;

2.创建个方法实现水印功能
- (void)viewDidLoad {
[super viewDidLoad];

UIImage *bgImage = [UIImage imageNamed:@""];

//创建一个位图上下文
UIGraphicsBeginImageContextWithOptions(bgImage.size, NO, 0.0);

//将背景图片画入位图中
[bgImage drawInRect:CGRectMake(0, 0, bgImage.size.width, bgImage.size.height)];

//将水印Logo画入背景图中
UIImage *waterIma = [UIImage imageNamed:@""];
[waterIma drawInRect:CGRectMake(bgImage.size.width - 40 - 5, bgImage.size.height - 40 - 5, 40, 40)];

//取得位图上下文中创建的新的图片
UIImage *newimage = UIGraphicsGetImageFromCurrentImageContext();

//结束上下文
UIGraphicsEndImageContext();

//在创建的ImageView上显示出新图片
self.neImage.image = newimage;

//压缩新照片为PNG格式的二进制数据
NSData *data = UIImagePNGRepresentation(newimage);

//将图片写入到手机存储中
NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"new.png"];
[data writeToFile:path atomically:YES];

}

//1.加载原图
UIImage *oldImage = [UIImage imageNamed:@"me"];

//2.获取位图上下文
CGFloat bigCic = oldImage.size.width + 2 * 2;
UIGraphicsBeginImageContextWithOptions(CGSizeMake(bigCic, bigCic), NO, 0.0);

//3.画大圆
[[UIColor whiteColor] set];
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextAddArc(ctx, bigCic * 0.5, bigCic * 0.5, bigCic * 0.5, 0, M_PI * 2, 0);
CGContextFillPath(ctx);

//4.画小圆
CGFloat smallCic = oldImage.size.width * 0.5;
CGContextAddArc(ctx, bigCic * 0.5 , bigCic * 0.5, smallCic, 0, M_PI * 2, 0);
CGContextClip(ctx);

//5.画图
[oldImage drawInRect:CGRectMake(2, 2, oldImage.size.width, oldImage.size.height)];

//6.获取新图
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

//7.结束上下文
UIGraphicsEndImageContext();

//8.显示新图
self.IconView.image = newImage;

//9.写入到手机存储
NSData *data = UIImagePNGRepresentation(newImage);
NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"newClip.png"];
[data writeToFile:path atomically:YES];

//1.开启位图上下文
UIGraphicsBeginImageContextWithOptions(self.view.frame.size, NO, 0.0);

//2.渲染截图
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];

//3.获取新图
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

//4.写入到手机存储
NSData *data = UIImagePNGRepresentation(newImage);
NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"newClip.png"];
[data writeToFile:path atomically:YES];

//5.关闭上下文
UIGraphicsEndImageContext();