Template Variation

Using the Duplicate option in Temmplate Manager appears to accomplish nothing. I daresay it's just me! What follows describes how to make and use a variant of the Default Template [Atomic in this case] and apply it to certain Articles only, but not all. I imagine the procedure would be similar for any other template. 

Download to your computer the whole of the Template you wish to duplicate. Create a NEW directory and give it a different name from that of the Template you downloaded. Copy ALL the files from within the downloaded Template into your the NEW directory. Edit the templateDetails.xml file in the NEW directory, to change the entry for the Template's 'NAME' to the NEW name. Depending on what you plan to do with the NEW template there are other changes you could also make at this point to the templateDetails.xml file, in particular renaming or adding to the positions. Save and Close.

TO CREATE A NEW POSITION. Let's call it newposition. In the templateDetails.xml file, add the name newposition to those listed in positions. Depending on what you want to accomplish with the new position you might add something like this in the template's index.php (see below)

<?php if($this->countModules('newposition')) : ?>
 <div class="whatever span-11 append-1"><jdoc:include type="modules" name="newposition" />
 </div>
 <?php endif; ?>

which, using the default BluePrint Grid in the Atomic template, would occupy half the page and in which you could then insert a new custom HTML module, also called newposition. Or you might want to use the new position to re-iterate your website name in which case something like this woiuld do;

<?php if($this->countModules('newposition')) : ?>
<h1><?php echo $app->getCfg('sitename'); ?></h1>
<?php endif; ?>

ZIP THE NEW TEMPLATE! One way in Windows, in case you don't know; right click on the NEW directory > SEND TO > ZIP FOLDER.

Note: the above edits to the index.php and templateDetails.xml could be made after the new varied template is installed.  

From the Back End of your Joomla website go to Extension Manager and install the NEW template ZIP in the same way you would any other. One way is; under Upload Package File > Choose File and browse to your NEW zip and > Upload and Install. So long as the message confirms that the Template has been successfully installed all should be well. There may be 'errors' reported but they can probably be disregarded so long as installation is also confirmed.

Go to Template Manager. The default view is the Styles tab but you need to click the Templates tab which takes you to Template Manager: Templates where your NEW template should now be listed. Yesss! Click on its name which takes you to Template Manager: Customise Template. From there you can make other edits to the Main Page Template in the Template Master Files pane and in the Stylesheets pane make any edits you want to the CSS. It is these changes that will actually alter the appearance or behaviour of your NEW variant Template. Save and Close

Back to Template Manager: Styles and click on the NEW template's name. On the lower half of next page there is a panel for Menu Assignment. Put checks alongside any articles etc to which you want specifically to apply the NEW template.

Save and Close - job done!

If you want to see an example in operation, use the menu to select the GRIDS Article which has a NEW, slightly modified Main Page Template that displays the grid pattern in the background whereas the other pages do not.