1、字符串转换成图片

- (UIImage *)imageFromString:(NSString *)string attributes:(NSDictionary *)attributes size:(CGSize)size
{
    UIGraphicsBeginImageContextWithOptions(size, NO, 0);
    [string drawInRect:CGRectMake(0, 0, size.width, size.height) withAttributes:attributes];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return image;
}

2、view 转换成图片

- (UIImage *)imageForView:(UIView *)view
{
    UIGraphicsBeginImageContextWithOptions(view.bounds.size, NO, 0);

    if ([view respondsToSelector:@selector(drawViewHierarchyInRect:afterScreenUpdates:)])
        [view drawViewHierarchyInRect:view.bounds afterScreenUpdates:YES];
    else
        [view.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return image;
}