How to Work with Multiple Objects in iBooks Author
iBooks Author lets you control the appearance of objects by adjusting their stacking order. When objects overlap each other, their stacking order determines how they overlap and thus what parts are visible — as if you laid a series of cards on top of each other. (You can think of stacking as positioning objects relative to each other in the third — or z — dimension, whereas positioning them on the page addresses the x and y dimensions.)
By default, the stacking order is determined by when an object was created or added; later objects are above earlier objects in the stacking order and obscure those earlier objects where they overlap. But you can change the stacking order by selecting an object and using the following commands:
Move to the top of the stacking order. Choose Arrange→Bring to Front or press Shift+Command+F.
Move up one level. Choose Arrange→Bring Forward or press Option+Shift+Command+F.
Move to the bottom of the stacking order. Choose Arrange→Send to Back or press Shift+Command+B.
Move down one level. Choose Arrange→Send Backward or press Option+Shift+Command+B.
Often, when you have multiple related objects, you want to group them together so that you can move them as one object and prevent an individual element from being accidentally moved or resized. Grouping objects also lets you apply various commands and formatting to all the objects at the same time.
To create a group, select the objects you want in it, and then choose Arrange→Group or press Option+Command+G. To ungroup an object group, select the group, and then choose Arrange→Ungroup or press Option+Shift+Command+G.
If you select multiple objects, iBooks Author can align them for you. Choose Format→Arrange Objects, and then choose the desired alignment from the submenu, which contains the options Left, Center, Right, Top, Middle, or Bottom. All objects are aligned with the object furthest in the direction you select. For example, if you choose Left, all selected objects are aligned to the leftmost object in the group.
Also, if you select multiple objects, you can have iBooks Author distribute them evenly: Choose Format→Distribute Objects→Horizontally (or Vertically) depending on how you want to distribute them.
If the objects are already spaced so that they don’t overlap in the direction in which you’re distributing them, the objects are kept within the area they currently occupy and spaced evenly within that area. But if the objects overlap in the direction in which you’re distributing them, iBooks Author moves them so that they don’t overlap; instead, it has them abut each other along the chosen direction, which enlarges the area the group occupies.