Put 0-point of ruler EXACTLY in center of page

[Nedlaw]

Hi. Using ID 19.2 under Windows 11.

Summary: This one has me puzzled. I want to put the 0-point of the Hz ruler EXACTLY in the center of a page of non-standard width. How?

Detail: I'm working on a book cover. Because of spine and trim considerations, the cover (a single page, not a spread) must be 17.60674" inches wide. This includes the front and back cover and the spine width. The spine is the center of the cover, and everything is measured to the right or to the left of the centerline of the spine. A quick calculation of 17.60674/2 = 8.80337" from the center to the trim edge of the single page. But I can't seem to find a way to center the 0-point of the Hz ruler exactly on the middle of this 17.60674" distance. (Yeah, I know ID only goes to 4 decimal places and doesn't show the final number 4; the least of my concerns.) I can't seem to figure out how to do this with precision. It seems like I should just be able to click something and say "Center."

Information on-line provides several methods of setting the 0-point -- right-click the ruler, and...

• Ruler per page puts 0-point on the left edge of the page. (not what I need)
• Ruler per spread puts the 0-point on the left edge of the spread (not working with a spread; don't want the ruler on the left edge)
• Ruler on spine puts the 0-point on the spine (which in the case of a single page is interpreted as the left edge of the page)

Other instructions say simply drag the intersection of the rulers to "any place you want." But "any place" measured by Mark 1 eyeball is not precise enough, I need to specify the center -- plus, once a ruler has been placed "more or less" at the center of the page, any attempt to adjust the ruler's 0-point shows the DIFFERENCE between the previous position and the new position, rather than an absolute position.

I've looked at the Info panel, the Properties panel, and the X-position in the ribbon, and it's not obvious to me how to place the 0-point of the Hz ruler at the center of whatever page size I'm working with. I can't believe no one has ever needed to do this but me, so I have missed the technique.

How do I place the 0-point of the Hz ruler at the center of a single page -- accurately?

Thanks as always to the community.

-j

[rob day · Accepted solution]

Hi @Nedlaw , You could draw out a guide and set its exact position from the transform panel.

It can also be easily scripted—this would set the zero point x to the active page’s center:

var b = app.activeWindow.activePage.bounds
app.activeDocument.zeroPoint = [(b[3]-b[1])*.5,0]

Also, maybe look at this book cover 3-page technique, where all you have to do is adjust the middle page’s width (the spine) and the cover and back cover will follow:

https://community.adobe.com/t5/indesign-discussions/how-to-set-out-a-book-cover-with-indesign-includ...

[Nedlaw]

That 3-page technique is certainly interesting. I will have to try both that and setting the 0-point to the middle of the spine via scripting. Thanks very much.

This may be the right answer; will know after I try.

-j

[James Gifford—NitroPress]

I had to be convinced the 3-page method was worth the trouble; I now use nothing else. It's especially valuable when, for example, you have to tweak the wrap width for varying POD vendors like KDP and Lulu, and for books that are occasionally updated or expanded (and thus need yet another thickness/wrap tweak).

Well worth adding to your 'toolkit,' as comfortable as you might be with single-sheet cover layout.

[Nedlaw]

I tried the 3-page method and it worked very well. I was even able to place a guide in the center of the spine panel using Align. You know, every day you learn more about InDesign and layout. It never fails.

Thanks to all for the help. I will try the script for centering the ruler. I still say that the ability to center a ruler on a page would be a benefit.

-j

[Brad @ Roaring Mouse]

The lower-tech method is to simply draw a rectangle the size of your page then drag the rulers to snap to the center points of the respective side(s). Then, if you want to zero your ruler to that spot, just drag your ruler origin to snap to those guides.