iOS 截图 截取屏幕

// 从view上截图- (UIImage *)getImage {        UIGraphicsBeginImageContextWithOptions(CGSizeMake(150, 150), NO, 1.0);  //NO，YES 控制是否透明    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();    UIGraphicsEndImageContext();    // 生成后的image        return image;}// 根据给定得图片，从其指定区域截取一张新得图片-(UIImage *)getImageFromImage{    //大图bigImage    //定义myImageRect，截图的区域    CGRect myImageRect = CGRectMake(70, 10, 150, 150);    UIImage* bigImage= [UIImage imageNamed:@"mm.jpg"];    CGImageRef imageRef = bigImage.CGImage;    CGImageRef subImageRef = CGImageCreateWithImageInRect(imageRef, myImageRect);    CGSize size;    size.width = 150;    size.height = 150;    UIGraphicsBeginImageContext(size);    CGContextRef context = UIGraphicsGetCurrentContext();    CGContextDrawImage(context, myImageRect, subImageRef);    UIImage* smallImage = [UIImage imageWithCGImage:subImageRef];    UIGraphicsEndImageContext();    return smallImage;}