Recently I was creating a white paper template in Word for a client and needed to insert some custom Picture Content Controls for photos that would be inserted by users. The designer had specced round-cornered pictures, but Picture Content Controls (PCC) have square corners. It didn't take long to figure out that after selecting the PCC, I could choose the Picture Tools>Format tab of the Ribbon, then apply a Picture Style. I chose the rounded corners with reflection (fifth icon over in Word 2010), then removed the reflection.
Now I had rounded corners, but also another problem. Word keeps the corner radius in proportion to the box size, so resizing the PCC up to the right size made the radius much larger than the design. Unlike AutoShapes, Content Controls will not display a yellow radius handle to adjust the radius. I also tried resizing the PCC before applying the Picture Style, but got the same big corners.
A Picture Content Control with default corner radius.
Custom Picture Content Controls XML
When I'm stuck, I crack open the XML. Can't leave it alone! If you've never opened Office files to edit their XML, read XML Hacking: An Introduction. If you're using a Mac, you should also read XML Hacking: Editing in OS X. All document content is in word\document.xml, so I opened it and started searching. In some respects, a PCC is handled like an ordinary picture, so I found it inside a <w:drawing> tag. The information I was looking for was in this subsection:
<a:off x="0" y="0"/>
<a:ext cx="3222172" cy="4576355"/>
<a:gd name="adj" fmla="val 8594"/>
When I spotted the line <a:prstGeom prst="roundRect">, i was pretty sure that's what I was looking for. But inside that tag, there were only 2 parameters. I went for the fmla tag and change the value from "val 8594" to "val 4000". Because I'm experimenting, I make only 1 change, then zip the XML to test. If you make several changes and the file doesn't open, it can take a long time to find the error.
I reopened the Word file. Success! The corner radii were about half the size. Then I just had to try several values until I found one that match the designer's intent. Keep in mind that the fmla value is not setting any particular radius size, it's setting the ratio of the curve to the size of the picture. So you should make the placeholders the correct size first, then try out fmla values to get the radius you want at those dimensions.
You don't always get lucky with parameters. A few lines down I spied another setting that looked like it could be useful. While you can set the PCC border in the program interface, you can't set the fill color. However, in the XML, I saw these tags:
Unfortunately, changing these values had no effect on the color of the Content Control. So what do these tags do? Search me, maybe someone at Microsoft knows. But I was happy to be able to set the radii to my preference. Here's the final result:
A custom Picture Content Control with smaller corner radii.