Within these templates I have the need to take an arbitrary image asset of any size, and scale it proportionally to fit inside a well defined area. This could be a thumbnail, or a larger version of the photo at hand. What I found myself doing is replicating the same template code over and over again in order to produce the output I desired throughout the template set. Here is the template code I was using:

<MTSetVarBlock name="width" trim="1"><MTEntryAssets><MTAssetProperty 
    property="image_width"></MTEntryAssets></MTSetVarBlock>
<MTSetVarBlock name="height" trim="1"><MTEntryAssets><MTAssetProperty 
    property="image_height"></MTEntryAssets></MTSetVarBlock>
<mt:if name="width" gt="$height">
    <MTSetVarBlock name="img"><MTEntryAssets><mt:AssetThumbnailLink width="90" 
        regex_replace="/^<a[^>]*>(<img[^>]*>)<\/a>$/","$1" /></MTEntryAssets></MTSetVarBlock>
<mt:else>
    <MTSetVarBlock name="img"><MTEntryAssets><mt:AssetThumbnailLink height="90" 
        regex_replace="/^<a[^>]*>(<img[^>]*>)<\/a>$/","$1" /></MTEntryAssets></MTSetVarBlock>
</mt:if>

Yikes.

To complicate things further, each time I cut and pasted this code around I had to modify it slightly depending upon the size of the photo I wanted to output. This presented the following problems:

• my template code was getting very messy.
• my template code was getting harder and harder to update because I had the same code in multiple places

What I found myself in need of is something a developer might call a "function" or "macro." In layman's terms, I needed a way to write this template code once, and then to invoke along with a few parameters in order to change its behavior and output as needed.

Luckily, Movable Type has exactly what I needed: a little template tag called MTSetVarTemplate. This template tag allowed me to define just such a macro so that I could reduce all of the complicated template code above into something far simpler:

<MTVar name="photo" max_size="90">

Wow, what an improvement!

<mt:ignore>
  This template module is responsible for outputting the associated image with the current
  photo/entry in context. You can pass in the max_size parameter to control the size of 
  the image.
  Example:
    <mt:getvar name="photo" max_size="90">
</mt:ignore>
<MTSetVarTemplate name="photo">
<MTSetVarBlock name="width" trim="1"><MTEntryAssets><MTAssetProperty property="image_width"></MTEntryAssets></MTSetVarBlock>
<MTSetVarBlock name="height" trim="1"><MTEntryAssets><MTAssetProperty property="image_height"></MTEntryAssets></MTSetVarBlock>
<mt:if name="width" gt="$height">
        <MTSetVarBlock name="img"><MTEntryAssets><mt:AssetThumbnailLink width="$max_size" regex_replace="/^<a[^>]*>(<img[^>]*>)<\/a>$/","$1" /></MTEntryAssets></MTSetVarBlock>
<mt:else>
        <MTSetVarBlock name="img"><MTEntryAssets><mt:AssetThumbnailLink height="$max_size" regex_replace="/^<a[^>]*>(<img[^>]*>)<\/a>$/","$1" /></MTEntryAssets></MTSetVarBlock>
</mt:if>
<mt:getvar name="img" trim="1">
</MTSetVarTemplate>

This is still a lot to chew on, so let me break down exactly what is going on:

• First, I use the <mt:ignore> tag to document what I had done and allow others to more easily re-use the module I created.
• I define the name of the macro by using the name attribute on the <mt:setvartemplate> tag.
• I invoke the macro, by using the <mt:getvar> tag.
• I am able to access parameters I pass into the macro using a common programming syntax, in this case using the $max_size variable.
• I am able to pass parameters into the macro by including them in my <mt:getvar> tag like any other attribute. For example (notice the max_size attribute corresponding to the variable of the same name inside of my macro):

I can't tell you how pleasantly surprised to find this feature. Using it greatly improved the readability of my templates, and also made them much each to maintain over time. And now looking back i can think of a million places through out my templates on every site I have ever worked on where this could really help make my template simpler and easier to maintain.

Every once in a while a plugin is created for Movable Type that makes you wonder, “why hasn’t anyone created this until now?” And the most recent plugin that I have installed on majordojo is no exception. Andy Yako-Mink, inspired by a ProNet conference call, created a plugin named “Cat Calendar.” But before you start imagining a 365 Cat-a-Day desk calendar for your blog, let me dispel any preconception you might have about this plugin. Simply put, Cat Calendar paginates Category Archive pages by date.

But why do I think this is so significant?

First, one of the consequences of Movable Type’s archiving system is that over time as you accumulate more and more content (which for a product that has been around for 5+ years is not completely unlikely) rebuilding specific pages becomes a very expensive operation. Category archives in particular because over time they only get larger. Rebuilding a single Category Archive page for example requires Movable Type to load a large number of entries into memory to be published to a single file. This results in a large memory foot print for Movable Type during the rebuild process; and for others that host more popular blogs it becomes a point of instability.

There is another benefit of Cat Calendar that cannot be overlooked: more page turns. By breaking really large category archive pages into multiple pages, you create greater potential for readers to browse multiple pages of your site by encouraging them to explore more posts within a category. As they browse and explore your blog, they generate more page turns, which if you are familiar with advertising is directly related to the earning potential of your blog; no mater which way you cut it, greater page volume results in higher ad impressions which in turn results in higher advertising revenue.

Installing Cat Calendar is easy and Andy has good instructions on how to do so. In fact, it is refreshing to see a plugin integrate so cleanly and completely into the Movable Type user experience. I encourage all Movable Type users: get Cat Calendar now, and throw some scratch Andy’s way. He deserves it.

• Byrne’s Category Archive Template
• Byrne’s Date-Based Category Archive Template