iOS_UIImage_图片剪切

- (UIImage *)imagecutWithRect:(CGRect)rect {

    CGImageRef subImageRef = CGImageCreateWithImageInRect(self.CGImage, rect);

    CGRect smallRect = CGRectMake(0, 0, CGImageGetWidth(subImageRef), CGImageGetHeight(subImageRef));

    // 开启图形上下文
    UIGraphicsBeginImageContext(smallRect.size);

    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextDrawImage(context, smallRect, subImageRef);

    UIImage * image = [UIImage imageWithCGImage:subImageRef];

    // 关闭图形上下文
    UIGraphicsEndImageContext();

    CGImageRelease(subImageRef);

    return image;
}

使用

- (UIImageView *)imageView {
    if (_imageView == nil) {
        self.imageView = [[UIImageView alloc] init];
        self.imageView.backgroundColor = [UIColor redColor];

        UIImage * image = [UIImage imageNamed:@"1.jpg"];
        // 截取原图中间300*300
        CGFloat cutImageWH = 300;
        CGFloat cutImage_x = (image.size.width - 300) / 2;
        CGFloat cutImage_y = (image.size.height - 300) / 2;

        self.imageView.image = [image imagecutWithRect:CGRectMake(cutImage_x, cutImage_y, cutImageWH, cutImageWH)];
    } return _imageView;
}