eiffel-org/documentation/current/solutions/gui-building/eiffelvision-2/eiffelvision-library-reference-manual/index.wiki

[[Property:title|EiffelVision Library Reference Manual]]
[[Property:weight|1]]
[[Property:uuid|b343b38b-c8b2-4247-072d-ecc1bc3e387a]]
EiffelVision 2 is a platform independent Graphical User Interface (GUI) library that allows easy, simultaneous development of Windowed applications for both Windows & Unix based platforms. Heavily relying on EiffelBase library, EiffelVision 2 has been designed primarily with ease of use in mind. By reusing EiffelBase structures, existing, as well as new Eiffel users will find EiffelVision to be surprising intuitive and easy to use. In no time, users will be producing good-looking Windowed application skeletons, of which will run on a multitude of platforms with no manipulation of code. 
The EiffelVision 2 library includes the following interface clusters: 
* A [[Kernel| kernel]]  cluster that includes classes that are key to a EiffelVision 2 application. The main class being [[ref:libraries/vision2/reference/ev_application_chart| EV_APPLICATION]]  which is the main entry point of all EiffelVision 2 applications. 
* A [[Widgets| widgets]]  cluster containing classes that used to create EiffelVision 2 widgets. Widgets are the visible objects that the user sees and interacts with on the desktop, examples of widgets are windows, buttons and labels. 
* An [[Items| items]]  cluster includes the classes needed to create items, items can be thought of as widgets that are contained within only a certain type of widget, such as an [[ref:libraries/vision2/reference/ev_list_chart| EV_LIST]]  that may only contain objects of type [[ref:libraries/vision2/reference/ev_list_item_chart|EV_LIST_ITEM]] . Items provide an abstract way of dealing with an item widget's internal data structures and provide in many cases the same functionality that a widget does. 
* An [[Events| events]]  cluster containing classes that allow for user initiated events, such as the clicking of a button to be dealt with via the use of a linked list of agents ( [[ref:libraries/vision2/reference/ev_action_sequence_chart|EV_ACTION_SEQUENCE]] ). Agents can be thought of as an object that encapsulates a certain procedure. When a user clicks a button on the screen, the corresponding [[ref:libraries/vision2/reference/ev_button_chart| EV_BUTTON]]  object has its associating pointer_button_press_actions fired and this in turn, fires all of the agents held within, thus calling all of the procedures represented by the agents. Every widget and item has a certain number of [[ref:libraries/base/reference/action_sequence_chart|ACTION_SEQUENCE]]  objects that are linked with a certain type of event. 
* A [[Properties| properties]]  cluster contains classes that allow for the customization of Vision 2 widgets and items. Classes such as [[ref:libraries/vision2/reference/ev_colorizable_chart|EV_COLORIZABLE]]  and [[ref:libraries/vision2/reference/ev_fontable_chart|EV_FONTABLE]]  contain routines that allow for color and fonts to be altered for a widget or item respectively. 
* A [[Support| support]]  cluster includes classes that provide more professional touches to an application, whether these are keyboard shortcuts ( [[ref:libraries/vision2/reference/ev_accelerator_list_chart|EV_ACCELERATOR_LIST]] ) or graphical output ( [[ref:libraries/vision2/reference/ev_graphical_format_chart|EV_GRAPHICAL_FORMAT]] ) for drawable widgets such as [[ref:/libraries/vision2/reference/ev_pixmap_chart|EV_PIXMAP]] . 
* A [[Figures| figures]]  cluster that allows for the projection of two-dimensional shapes (figures) on to an [[ref:libraries/vision2/reference/ev_drawable_chart|EV_DRAWABLE]]  or printer via the use of an [[ref:libraries/vision2/reference/ev_projector_chart|EV_PROJECTOR]] . 

To see differences between released versions of EiffelVision, click [[Revisions and Bug Fixes|Here]]