Event fired before a zoom action is applied. Function takes arguments evt and ui. Use ui.previousZoom.left to get the previous zoom window left position as a fraction of the absolute width of the target. Use ui.previousZoom.width to get the previous zoom window width as a fraction of the absolute width of the target. Use ui.newZoom.left to get the new zoom window left position as a fraction of the absolute width of the target. Use ui.newZoom.width to get the new zoom window width as a fraction of the absolute width of the target. Use ui.owner to get reference to igZoombar.
Target Platforms: Windows 8.1, Windows 8.1, Windows 8, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
