6 Answers, 1 is accepted
For the time being we do not plan to provide such a feature, because it can be achieved with a little bit of CSS and an image. The idea I can give you is the following:
1. Use IE DevToolbar or FireBug to inspect the parent element of the content are <iframe />. You will notice that it is a <td /> with a .reContentCell CSS class name.
2. Create a large ruler image with ticks and measurement units (for example 2000 x 2000 pixels, the idea is that it should be larger than your largest RadEditor) with a vertical and horizontal ruler. It should look like a vertically flipped "L".
3. Add padding-top to .reContentCell equal to the height of the horizontal ruler (the ruler itself, not the height of the entire image). Let's assume that it is 20 pixels high.
4. Add padding-left to .reContentCell equal to the width of the horizontal ruler (the ruler itself, not the width of the entire image). Let's assume that it is 20 pixels wide.
5. In your stylesheet use a CSS selector like this one:
td.reContentCell
{
padding: 20px 0 0 20px !important;
background: url('Ruler.gif') no-repeat !important;
}
Greetings,
Rumen
the Telerik team

Hi,
I was just looking to see whether there had been any change to Telerik's position on this since this post about 4 years ago? We demonstrated the RadEditor to a group of users today who are all MS Word users and they wanted to know how we could show the ruler.
Thanks and best regards
Peter
Hi Peter,
Rulers are not something that is generally available for HTML because it does not have a concept of paging like an MS Word document has. Thus, rulers are not available in RadEditor.
You can, however, see the size of the HTML elements in the DomInspector module. I am attaching creenshots that shows this. Note that many HTML elements are block elements so they do not need/have width specified which should be expected.
If you want to create paged documents, I can suggest looking into the RadRichTextBox for Silverlight: http://demos.telerik.com/silverlight/#RichTextBox/TelerikEditor.
Regards,
Telerik

Hi Marin,
Thanks for the update. I understand the rationale. I'm not sure I understand the point about the Silverlight Rich Text editor though. How would this be incorporated into a standard ASPX page? I'll forward this to the developers so they're aware of what the tool can't do as well as what it can.
One of our challenges is that we have to produce print-ready PDF documents from the content we enter into the RadEditor. Even though we encourage users(external to our organisation) to look at things online, our contract with a Federal Government department stipulates that we generate output that can be given directly to the printers. We're going to review the InDesign APIs because even though we got very close exporting content to MS Word it wasn't good enough for publishing. The content wasn't created using RadEditor but it was HTML.
We'll keep researching how this will work.
Thanks and best regards
Peter
Hello Peter,
Silverlight apps can be added to any page that results in HTML in the browser, all you need is the XAP file the Silverlight project will produce. Here is a tutorial: https://msdn.microsoft.com/en-us/library/cc189089(v=vs.95).aspx.
As for PDF export - RadEditor for ASP.NET AJAX offers this feature: http://demos.telerik.com/aspnet-ajax/editor/examples/import-export/pdf-export/defaultcs.aspx. You may also find useful this article: http://docs.telerik.com/devtools/aspnet-ajax/controls/editor/functionality/toolbars/buttons/examples/page-break-button.
Regards,
Marin BratanovTelerik

Hi Marin,
Thanks for the quick response and the additional links. The PDF issue depends on whether we can explicitly create a page size that includes trim and bleed, i.e. the ability to add extra space to the page which we can do in InDesign but were not able to do in MS Word, the difference of course being that InDesign is a publishing tool and MS Word is not.
I'll forward these details to the developers as well and see what we think is the best way to do this moving forward.
Thanks and best regards
Peter