ios view转图片

方法一：View的大小不大于手机屏幕

#pragma mark - 方法一：View的大小不大于手机屏幕
- (UIImage *)GetmakeImageWithView:(UIView *)view andWithSize:(CGSize)size
{
    // 下面方法，第一个参数表示区域大小。第二个参数表示是否是非透明的。如果需要显示半透明效果，需要传NO，否则传YES。第三个参数就是屏幕密度了，关键就是第三个参数 [UIScreen mainScreen].scale。
    UIGraphicsBeginImageContextWithOptions(size, NO, 0.0);
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

方法二：View的大小大于手机屏幕

#pragma mark - 方法二：View的大小大于手机屏幕
- (UIImage *) snapshotWithScrollView:(UIScrollView *)scrollView
{
    UIImage * image = nil;
    UIGraphicsBeginImageContext(scrollView.contentSize);
    
    CGPoint savedContentOffset = scrollView.contentOffset;
    CGRect savedFrame = scrollView.frame;
    scrollView.contentOffset = CGPointZero;
    scrollView.frame = CGRectMake(0, 0, scrollView.contentSize.width, scrollView.contentSize.height);
    [scrollView.layer renderInContext: UIGraphicsGetCurrentContext()];
    image = UIGraphicsGetImageFromCurrentImageContext();
    scrollView.contentOffset = savedContentOffset;
    scrollView.frame = savedFrame;
    
    UIGraphicsEndImageContext();
    if (image != nil) {
        return image;
    }
    return nil;
}

截取view中某个区域生成一张图片

#pragma mark - 截取view中某个区域生成一张图片
- (UIImage *)shotWithView:(UIView *)view scope:(CGRect)scope
{
    CGImageRef imageRef = CGImageCreateWithImageInRect([self GetmakeImageWithView:view andWithSize:view.bounds.size].CGImage, scope);
    UIGraphicsBeginImageContext(scope.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGRect rect = CGRectMake(0, 0, scope.size.width, scope.size.height);
    CGContextTranslateCTM(context, 0, rect.size.height);//下移
    CGContextScaleCTM(context, 1.0f, -1.0f);//上翻
    CGContextDrawImage(context, rect, imageRef);
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    CGImageRelease(imageRef);
    return image;
}