Gravatars, and how not to show them
Bandwagon-jumper that I am, I’ve now enabled Gravatars on this site. If you have one of these personal blog icons set up for the email address you use to comment, it will show up next to your comments.
The basic implementation instructions don’t mention how to not display the gravatar for those commenters who don’t have one, so here is how I accomplished it.
The only way to tell that a person doesn’t have an avatar is to check the dimensions of the image returned by the function call – if it is a 1×1 .gif, then no ‘official’ image is stored. To check the dimensions we can use the PHP getimagesize() function, which creates an array containing the width, height, type and attributes of the image. By checking either the width or height we can establish whether there is an image to display or not:
<?php
$gravatar = getimagesize("<txp:gravatar />");
if ($gravatar[ 0 ] != 1) echo "<img
src="<txp:gravatar />&size=50"
alt="Commenter's gravatar" class="gravatar" />";
?>
This is obviously only relevant to Textpattern blogs, but could be used on any PHP-based system. Note that the spaces inside the square brackets should be removed.
Filed under: Internet, Textpattern.
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Comments
- Stuart
- 1388 days ago
- This looks rather good. I hadn’t spotted this one before. I’ve been trying to implement smilies but I might not bother now. I have to say that I understood the “hack” bit but they lost me a little on the usage. Am I right in thinking that their tag goes into the “comment” form as opposed to the “comment_form” form if you understand the difference and then do I presume that your bit of PHP above replaces their tag? And then again does the “size” attribute in your PHP or their tag reduce or enlarge anyone’s avatar to give a uniform size? And what’s a “G” rating? Do I ask too many questions?
- #1
- Matthew Pennell
- 1388 days ago
- Yes, their tag goes into the ‘comment’ form, and my PHP replaces it altogether.
The size attribute resizes any gravatar (bicubically, apparently – don’t ask me what that means), and the ratings are the same as the US cinema ratings; they allow you to prevent any explicit gravatars from being displayed on your site. - #2
- Jonathan M. Hollin
- 1387 days ago
- What a coincidence!
I made my comments system Gravatar-friendly a couple of days ago Matthew.
Today, I was looking through comments on some of my older posts to see if any of the posters had created a Gravatar. Yours was the only one I have found (so far).
So I clicked through to your site and the first thing I see is a post about Gravatars.
Welcome to the bandwagon mate! :-) - #4
- Jonathan M. Hollin
- 1387 days ago
- “bicubically, apparently dont ask me what that means”
I think it just means that you supply a single size value and the value is applied to both image dimensions (width & height).
It’s certainly not a dictionary word though! - #5
- Matthew Pennell
- 1386 days ago
- I see Richard Rutter over at Clagnut has nicked my PHP idea!
- #6
- Mathias Bynens
- 1386 days ago
- You know what they say—- great minds think alike :)
- #7
- Matthew Pennell
- 1385 days ago
- Not noticed it myself – you have broken my layout though; make longer comments!
- #9
- Paul Armstrong
- 1342 days ago
- What would be the best way to give people a default image if they don’t already have one?
- #10
- Matthew Pennell
- 1342 days ago
- Paul – luckily there is very little you have to do to show a default image; simply include a ‘default’ parameter in the query string pointing at your chosen default image:
&default=http%3A%2F%2Fwww.somesite.com%2Fsomeimage.jpg
Notice that you have to escape the special characters within the image URL.
Full instructions can be found at the official Gravatar site. Rob’s Zooiblog is a good example of using default images – note the “Null” image. - #11
- Paul Armstrong
- 1331 days ago
- Instead of doing that, since I am using Jon Hicks’ method of even and odd comment listings, I have two different background images for the gravatars. That way, there is some more randominity to the images when people don’t have gravatars.
- #12