Book -MegaZine3 页码，19/20■ See also:[1](http://vservu.com/_blog/MegaZine3_-_tips,_tricks_and_hints/post/How_to_achieve_best_qualities_with_JPG_files/) , book@zoomsnapzoomtween ■ Type:Number■ Default:0To allow setting the time (in ms) it takes to transition between zoom levels (smoother zooming).zoomwheel ■ Type:Boolean■ Default:true■ Aliases:wheelzoomDetermines whether to make use of the mousewheel for zooming in or out the actual pages (when minscale != maxscale). If disabled scaling will only take place via liquid scaling or via the API (or, if loaded, the navigationbar).Child Nodes The bookmay have chapterchild nodes, one for each chapter, to define the actual contents of the book.Two child nodes can be used to define an overall background of the book, backgroundfor a static, global background, and pagebackgroundfor a background bound to the page's position and size (i.e. it will also be scaled when zooming in or out). Those two nodes take any number of ASULelements as their children, which will then be displayed as their actual children on the stage. The variables for the parent size and height (pw, ph) will be the total space available to the engine for background(which is the whole stage size when using the release as it is), and the page width and height for the pagebackground. The origin (top left, coordinates 0,0) is the top left of the overall space available to the engine for the backgroundand the position of the top left corner of the book for the pagebackground.As of version 2.0.8 it is also possible to define an overall foreground via foreground, which may contain ASUL elements to be shown on top of everything else.Plugins may use additional nodes to let the user define additional properties, as does the sidebarplugin.Examples http://www.megazine3.de/doc/Book 2013/9/3