3.3 Window facilities

window defines the means for creating windows in applications. It defines the following important attributes:

• The events: onAboutToClose, onActivate, etc. are the facilities for specifying actions to be executed as consequence of user interactions.
• theMenubar and menubarType are the means for associating a menubar with this window. And menubarVisible controls whether the menubar should be visible.
• title is used for specifying the window title.
• position, frame and size are used to control the location of the window.
• floating controls whether this window will float on top of all other windows.
• show and hide is used to control the visibility of the window.
• showModal specifies that this window will be shown as a modal window.
• bringToFront, bringBack and bringBehind is used to control the stacking order of this window.
• target is used to control the keyboard focus within this window.
• windowItem is the central facility for defining the contents of windows. WindowItems can be attached to windows (more details later).
• type controls the appearance of the titlebar of the window: palette, dialog or normal.
• canvas is a subclass of windowItem, implementing a local coordinate system. Just as windows, more than one windowItem may be associated with a canvas. Canvas function as a mean for grouping windowItems within windows (or other canvasses).

windowItem is the central class for specifying the contents of windows (and canvasses). The contents of windows are one instance of canvas, simplifying the design.

• the events:ÊonVisibilityChanged, onFrameChanged, onFatherFrameChanged, onMouseUp, etc. are the means for specifying actions to be executed as the consequence of user interactions (directly or indirectly).
• father is a reference to the canvas (and thereby possibly the window), this windowItem is associated with.
• frame, position, move and size is used to control the location of the windowItem within the father canvas.
• bindLeft, bindRight, bindBottom and bindTop is used to control the behaviour of this windowItem when the father canvas has changed frame.
• show and hide is used to control whether this windowItem is visible on its father canvas.
• enable and disable is used to control whether this windowItem reacts to mouse and keyboard interactions.
• theCursor and cursorType is used to control the cursor to be displayed within this windowItem.
• drag and resize are facilities to be used for interactive manipulations of this windowItem.

canvas is the only windowItem subclass that allows attachment of other windowItems. In this respect, canvasses resemble windows (that uses a canvas to contain the windowItems of the window).