Core Toolbox

The core toolbox supports basic user-level elements such as windows, menus, and buttons, as well as programmer-level objects such as pens, bitmaps, and communication channels.

All of the core toolbox classes and procedures are contained in the wx@ signed unit, which is pre-defined in MrEd. It includes all of the classes, constants, and procedures defined in this manual that start with wx:, plus the wx@ unit itself. The pre-defined wx^ signature is the output signature of wx@.

The basic classes for user-level graphical elements are:

• wx:window% -- most user-level graphical elements are windows; frames, buttons, and canvases are all windows, but menus and menu bars are not; this class cannot be instantiated directly
• wx:frame% -- frames are top-level windows that can be dragged and re-sized by the user; frames can contain control item panels, canvases, and text windows
• wx:canvas% -- canvases are sub-windows used for arbitary drawing
• wx:panel% -- panels are canvases that contain control items or other canvases
• wx:dialog-box% -- dialog boxes are panels, each with its own top-level frame
• wx:item% -- control items are user-manipulated windows within a panel; the wx:item% class is only instatiated through a subclass:
  • wx:message% -- messages are static text controls with no user interaction
  • wx:button% -- buttons are clickable controls, each with a callback procedure
  • wx:radio-box% -- radio boxes are collections of mutually-exclusive radio buttons; when the user selects one radio button in a radio box, the previously selected radio button is unselected.
  • wx:text% -- text items are simple editable text fields
  • wx:multi-text% -- multi-line text items are text fields that can contain carriage returns
  • wx:list-box% -- list boxes are scrollable lists of text choices; the user can select one or more items in the list
  • wx:choice% -- choice items are pop-up lists of text choices; the user can select on item in the list
  • wx:check-box% -- check boxes are clickable controls that maintain a checked or unchecked state
  • wx:slider% -- sliders are simple integer control items that graphically reflect the current value
  • wx:gauge% -- gauges are read-only displays for integer values
• wx:text-window% -- text windows are canvases used for simple text display or editing
• wx:menu% -- menus are pull-down or pop-up lists of text items; the user selects a menu item to trigger a callback action
• wx:menu-bar% -- menu bars are collections of top-level menus associated with a frame

The wx: window classes should rarely be instantiated directly; instances of these classes do not have automatic managmennt for their graphical size and location. Instead, for automatic geometry managment, create instances of the corresponding mred: classes (see Geometry Management Toolbox).

Most other classes in the core toolbox are for drawing. The destination of drawing commands is always a device context, or DC, and instance of wx:dc%. Different kinds of DCs are used for different kinds of drawing:

• wx:canvas-dc% -- canvas DCs are used for drawing to a canvas
• wx:memory-dc% -- memory DCs are used to draw into an offscreen bitmap
• wx:post-script-dc% -- PostScript DCs are used to draw into a PostScript file

Tools used for drawing include wx:pen% objects for drawing lines, wx:brush% objects for filling shapes, and wx:bitmap% objects for storing bitmaps.