12 Replies Latest reply on Jul 29, 2010 11:52 PM by marcusstringer

    exact center

    Adscp Level 1


      does anyone know if there's a shortcut way to figure out where the exact center of an indesign document is?

      a key command perhaps?


      i've looked online but can't find anything.



        • 1. Re: exact center
          [Jongware] Most Valuable Participant

          Call up the Document Page Setup dialog, divide the page size by two.


          Draw a rectangle covering the entire page, then type "/2" after its width and height in the Control panel.


          Draw a rectangle frame (the one that shows a big 'X' through it) covering the entire page.


          Draw a line from the top left to the bottom right corners, set the proxy to its center, click on the Horizontal (or vertical) flip button with Alt down.


          Set the ruler origin to top left of the page, then drag a horizontal guide on the right edge of the page. The guide is still selected when you release the mouse button, and its x-coordinate is in the control panel. Type "/2" after this coordinate and press Return. Repeat for vertical.


          Draw a text frame covering the entire page. Set its paragraph alignment to Centered, and the text frame options to Vertically centered. Insert a bullet -- its top center will be the page center.


          (CS4) Draw a rectangle, starting from any corner, down to the approximate center of the page -- with Smart Guides enabled, the dragged corner will display big fat smart guides, and the corner will snap into place.


          I may need some time to come up with another seven methods.

          • 2. Re: exact center
            Daniel Flavin Level 4

            what's his name coud script it, but, the long way is to use those math features that are so much fun in the control bar.

            Hit alt+ctrl+p to bring up the document setup (I'm assuming it is not easily memorized here), copy the width dimension to the clipboard.

            Drag a guide (or a frame with center proxy selected) and paste the clipboard contents into the x field along with the / (division symbol) 2. Effectively you are telling ID to use value n/2. (n divided by 2).

            Tough to explain, here's a screen shot. I set up a A4 document which I never would, and set my preferences to points, which I almost never do...



            math in field shot.png

            • 3. Re: exact center
              [Jongware] Most Valuable Participant

              Yeah, I forgot: Method #8: a Javascript.


              alert ("The center is " + app.activeDocument.documentPreferences.pageWidth/2 + "," + app.activeDocument.documentPreferences.pageHeight/2);

              • 4. Re: exact center
                Stix Hart Level 5

                That script must know something about the actual size of my A4 document that I don't!



                • 5. Re: exact center
                  Stix Hart Level 5

                  P.S.  Why do you want to know the exact centre?  Or to put it another way, what are you going to do with that information once you have it?  Knowing that will let us give you a better answer as to the fastest way to find it.

                  • 6. Re: exact center
                    [Jongware] Most Valuable Participant

                    It does. Internally, InDesign does not 'do' millimeters, all measurements are stored in points. Displaying a pt measurement into mm needs a calculation: mm*72.0/25.4, and then it gets rounded, because the floating point decimals inside ID only have about 16 significant digits.


                    The interface is friendly -- it displays, what? 2 or 3 decimals after the period, although on occasion it may suddenly decide to show the full number (I'm looking now at an image that has been scaled to "15.363379894914805%").

                    • 7. Re: exact center
                      [Jongware] Most Valuable Participant

                      Method #9: create a blank image in Photoshop. Draw a single black pixel in the center. Import into InDesign, scale up to page size. The black pixel will be in the exact center of your page (rounded off to the nearest scaled pixel size).

                      • 8. Re: exact center
                        [Jongware] Most Valuable Participant

                        I just checked: your A4 size is stored as


                              595.275591 pt x 841.889764 pt

                        which is (about) 210.000000158 x 297.000000078 mm, so there are some additional round-offs going on before the value gets into the script.

                        • 9. Re: exact center
                          Stix Hart Level 5

                          Very interesting...  So I assume that's why Illustrator suddenly jumps to 10.00001 mm when you're resizing something sometimes, it rounds the points conversion.

                          • 10. Re: exact center
                            [Jongware] Most Valuable Participant

                            I suppose.


                            The interesting factoid to glean from this is Illustrator seems to have only 1/100,000,000th of InDesigns accuracy. Perhaps it's time for the Illustrator programmers to update it to 64-bit floating point numbers.

                            • 11. Re: exact center
                              Peter Spier Most Valuable Participant (Moderator)

                              In CS4 or later, just turn on the smart guides, for pity's sake.

                              • 12. Re: exact center
                                marcusstringer Level 3

                                Or simply draw a box accros the witdh you want.

                                The blue dot in the middle of the box is the centre. Then drag a guide vertical guide on it, delete the box...


                                Just because you can, Doesn't mean you should....