2D Graphics > Managers > Basic Manager Features > Manager Views
 
Manager Views
Attaching multiple views to a manager allows your program to display graphic objects simultaneously in various configurations. This is illustrated in Figure 1.2.
Figure 1.2    Multiple Views Bound To a Manager
The following IlvManager member functions handle the binding of views to a manager:
*addView - Attaches a view to the manager. All events are then handled by the hierarchy of interactors in place in the manager.
*removeView - Removes a view from the manager view list. The view is no longer handled by the manager.
*IlvManager::getViews - Returns an array of pointers to all the views currently connected to the manager.
The following aspects of manager views are described in this section:
*View Transformations
*Double-buffering
View Transformations
Use the following IlvManager member functions to modify the transformer associated with the view (except for IlvManager::fitToContents, which modifies the size of the view):
*IlvManager::setTransformer
*IlvManager::addTransformer
*IlvManager::translateView
*IlvManager::zoomView
*IlvManager::rotateView
*IlvManager::fitToContents
*IlvManager::fitTransformerToContents
*IlvManager::ensureVisible
Example: Zooming a View
This accelerator zooms a view using a scaling factor of two:
static void
ZoomView(IlvManager* manager, IlvView* view, IlvEvent& event, IlAny)
{
IlvPoint pt(event.x(), event.y());
manager->zoomView(view, pt, IlvFloat(2), IlvFloat(2), IlTrue);
}
 
The point given in the zoomView argument keeps its position after the zoom. The last parameter forces the redrawing of the view.
Double-buffering
The double-buffering member functions can be used to prevent the screen from flickering when many objects are manipulated. For each manager view, this feature requires the allocation of a hidden bitmap the size of the view. Depending on the number of views and the color model, double-buffering may consume a large amount of memory.
The member functions that handle double-buffering are:
*IlvManager::isDoubleBuffering
*IlvManager::setDoubleBuffering
*setBackground
Note: You must use the setBackground member function to change the background color of a view in double-buffering mode.
Example
This function switches the double-buffering mode of the given view:
static void
ToggleDoubleBuffering(IlvManager* manager, IlvView* view)
{
manager->setDoubleBuffering(view,
!manager->isDoubleBuffering(view));
}
 

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