Package: GWindows.Base

Dependencies

with Ada.Finalization;
with System;

with GWindows.Types;
with GWindows.Drawing;
with GWindows.Drawing_Objects;
with GWindows.Colors;
with Interfaces.C;

Description

GWINDOWS - Ada 95 Framework for Win32 Development

G W I N D O W S . B A S E

S p e c

$Revision: 1.2 $

This is free software; you can redistribute it and/or modify it under terms of the GNU General Public License as published by the Free Soft- ware Foundation; either version 2, or (at your option) any later ver- sion. It is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License distributed with this; see file COPYING. If not, write to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

As a special exception, if other files instantiate generics from this unit, or you link this unit with other files to produce an executable, this unit does not by itself cause the resulting executable to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the executable file might be covered by the GNU Public License.

More information about GWindows and the latest current release can be located on the web at http://www.gnavi.org/gwindows

Header

package GWindows.Base is

Type Summary

`Action_Event`
`Base_Window_Access`
`Base_Window_Type` derived from `Limited_Controlled`
Overridden Operations:	`Finalize`
New Operations:	`Accelerator_Handle`, `Accelerator_Handle`, `Accelerator_Table`, `Attach`, `Attach_Control`, `Attach_Dialog`, `Attach_Dialog_Item`, `Border`, `Border`, `Capture_Mouse`, `Center`, `Center`, `Child`, `Client_Area_Height`, `Client_Area_Height`, `Client_Area_Size`, `Client_Area_Width`, `Client_Area_Width`, `Close`, `Control`, `Controlling_Parent`, `Create_Control`, `Disable`, `Dock`, `Dock`, `Enable`, `Enabled`, `Enabled`, `End_Dialog`, `Enumerate_Children`, `Fire_On_Context_Menu`, `Fire_On_Create`, `Fire_On_Destroy`, `Fire_On_Horizontal_Scroll`, `Fire_On_Pre_Create`, `Fire_On_Vertical_Scroll`, `First_Window`, `Focus`, `Focus`, `Freeze`, `Get_Canvas`, `Get_Font`, `Get_Full_Window_Canvas`, `Group`, `Group`, `Handle`, `Height`, `Height`, `Hide`, `Horizontal_Scroll_Bar`, `Horizontal_Scroll_Bar`, `ID`, `Is_Dialog`, `Is_Dialog`, `Is_Modal`, `Is_Modal`, `Keyboard_Support`, `Keyboard_Support`, `Last_Window`, `Left`, `Left`, `MDI_Client_Window`, `MDI_Client_Window`, `Modal_Result`, `Modal_Result`, `Move`, `Next_Tab_Stop`, `Next_Window`, `On_Command`, `On_Context_Menu`, `On_Context_Menu_Handler`, `On_Create`, `On_Create_Handler`, `On_Destroy`, `On_Destroy_Handler`, `On_Draw_Item`, `On_Filter_Message`, `On_Horizontal_Scroll`, `On_Horizontal_Scroll_Handler`, `On_Message`, `On_Notify`, `On_Pre_Create`, `On_Pre_Create_Handler`, `On_Vertical_Scroll`, `On_Vertical_Scroll_Handler`, `Order`, `Order`, `Parent`, `Parent`, `Point_To_Client`, `Point_To_Desktop`, `Previous_Tab_Stop`, `Previous_Window`, `Redraw`, `Set_Font`, `Show`, `Size`, `Tab_Stop`, `Tab_Stop`, `Text`, `Text`, `Text_Length`, `Thaw`, `Top`, `Top`, `Valid`, `Vertical_Scroll_Bar`, `Vertical_Scroll_Bar`, `Visible`, `Visible`, `Width`, `Width`
Inherited Operations:	`Initialize`
`Dock_Type`
`Enumerate_Function`
`Link_Type_Type`
`Location_Action_Event`
`Notification`
`Order_Position_Type`
`Pointer_To_Base_Window_Class`
`Pointer_To_Notification`
`Pre_Create_Event`
`Scroll_Event`
`Scroll_Request_Type`
`WNDCLASS`
Primitive Operations:	`Register_Class`

Constants and Named Numbers

CS_BYTEALIGNCLIENT : constant := 4096;

Class style: Align client area on x byte boundary

CS_BYTEALIGNWINDOW : constant := 8192;

Class style: Align window on x byte boundary

CS_CLASSDC : constant := 64;

Class style: DC shared by class

CS_DBLCLKS : constant := 8;

Class style: Send double click message to window

CS_GLOBALCLASS : constant := 16384;

Class style: Application global

CS_HREDRAW : constant := 2;

Class style: Redraw for horizontal change

CS_IME : constant := 65536;

CS_KEYCVTWINDOW : constant := 4;

CS_NOCLOSE : constant := 512;

Class style: Inhibit close on system menu

CS_NOKEYCVT : constant := 256;

CS_OWNDC : constant := 32;

Class style: DC for each window instance

CS_PARENTDC : constant := 128;

Class style: Use DC of parent

CS_SAVEBITS : constant := 2048;

Class style: Save screen image behind window

CS_VREDRAW : constant := 1;

Class style: Redraw for vertical change

Other Items:

use type Interfaces.C.unsigned;

Base_Window_Type

Base_Window_Type is the parent Class of all GWindows GUIs widgets. It is generally not used directly

type Base_Window_Type is
  new Ada.Finalization.Limited_Controlled with private;

type Base_Window_Access is access all Base_Window_Type;

type Pointer_To_Base_Window_Class is access all Base_Window_Type'Class;

procedure Finalize (Object : in out Base_Window_Type);

Cleans resources for dynamicly created windows. Will also close window if it is open.

procedure Accelerator_Table
   (Window  : in out Base_Window_Type;
    Name    : in     GString);

Set accelerator table for window from resource Name To specify a numeric resource use #XXXX where XXXX is the resource ID

procedure Border (Window : in out Base_Window_Type;
                  State  : in     Boolean          := True);

function Border (Window : in Base_Window_Type) return Boolean;

Border property

type Dock_Type is (At_Top, At_Left, At_Right, At_Bottom, Fill, None);

procedure Dock (Window : in out Base_Window_Type;
                To     : in     Dock_Type);

function Dock (Window : in Base_Window_Type) return Dock_Type;

Set requested docking location of this object GWindows.Windows provides a procedure Dock_Children that is called in the default On_Size handler that will dock windows based on this property

function Focus return Pointer_To_Base_Window_Class;

Returns the currently focused control/window

function Focus (Window : in Base_Window_Type)
               return Pointer_To_Base_Window_Class;

Returns the currently/last focused control of this window

procedure Focus (Window : in out Base_Window_Type);

Set keyboard focus to window or control

function First_Window (Window : in Base_Window_Type)
                     return Pointer_To_Base_Window_Class;

function Last_Window (Window : in Base_Window_Type)
                     return Pointer_To_Base_Window_Class;

function Next_Window (Window : in Base_Window_Type)
                     return Pointer_To_Base_Window_Class;

function Previous_Window (Window : in Base_Window_Type)
                         return Pointer_To_Base_Window_Class;

Return the window in the Z-Order

procedure Set_Font (Window : in out Base_Window_Type;
                    Font   : in     GWindows.Drawing_Objects.Font_Type);

procedure Get_Font (Window : in     Base_Window_Type;
                    Font   :    out GWindows.Drawing_Objects.Font_Type);

Window Font

procedure Group (Window : in out Base_Window_Type;
                 State  : in     Boolean          := True);

function Group (Window : in Base_Window_Type) return Boolean;

Start of control group property

procedure Keyboard_Support (Window : in out Base_Window_Type;
                            State  : in     Boolean          := True);

function Keyboard_Support (Window : in Base_Window_Type) return Boolean;

Support moving in/out of child window/control using the tab key, etc.

type Order_Position_Type is (Top,
                             Bottom,
                             Always_On_Top,
                             Not_Always_On_Top);

procedure Order (Window   : in out Base_Window_Type;
                 Position : in     Order_Position_Type);

Move window to position in layout order

procedure Order (Window       : in out Base_Window_Type;
                 After_Window : in     Base_Window_Type'Class);

Move window to position After_Window in layout order

procedure Horizontal_Scroll_Bar (Window : in out Base_Window_Type;
                                 State  : Boolean := True);

function Horizontal_Scroll_Bar (Window : in Base_Window_Type)
                               return Boolean;

Horizontal Scroll Bar State

procedure Vertical_Scroll_Bar (Window : in out Base_Window_Type;
                               State  : Boolean := True);

function Vertical_Scroll_Bar (Window : in Base_Window_Type) return Boolean;

Vertical Scroll Bar State

procedure Tab_Stop (Window : in out Base_Window_Type;
                    State  : in     Boolean     := True);

function Tab_Stop (Window : in Base_Window_Type) return Boolean;

Tab Stop property

procedure Text (Window : in out Base_Window_Type;
                Text   : in     GString);

function Text  (Window : in Base_Window_Type)
               return GString;

Text/Caption property

function Text_Length (Window : in Base_Window_Type) return Integer;

Legth of Text/Caption property

function Valid (Window : in Base_Window_Type) return Boolean;

If is a valid window object, ie. if it has been created and has not been destroyed

procedure Visible (Window : in out Base_Window_Type;
                   State  : Boolean := True);

function Visible (Window : in Base_Window_Type) return Boolean;

Visible state of window

procedure Enabled (Window : in out Base_Window_Type;
                   State  : Boolean := True);

function Enabled (Window : in Base_Window_Type) return Boolean;

Enabled state of window

procedure Left (Window : in out Base_Window_Type;
                Value  : Integer);

function Left (Window : in Base_Window_Type) return Integer;

Location of left side window

procedure Top (Window : in out Base_Window_Type;
               Value  : Integer);

function Top (Window : in Base_Window_Type) return Integer;

Location of top of window

procedure Width (Window : in out Base_Window_Type;
                 Value  : Natural);

function Width (Window : in Base_Window_Type) return Natural;

Width of window

procedure Height (Window : in out Base_Window_Type;
                  Value  : Natural);

function Height (Window : in Base_Window_Type) return Natural;

Height of window

procedure Size (Window : in out Base_Window_Type;
                Width  : in     Natural;
                Height : in     Natural);

Change size of window

procedure Client_Area_Size (Window : in out Base_Window_Type;
                            Width  : in     Natural;
                            Height : in     Natural);

Change size of window so that the client area will be widthxheight

procedure Client_Area_Width (Window : in out Base_Window_Type;
                             Value  : in     Natural);

function Client_Area_Width (Window : in Base_Window_Type) return Natural;

Width of window

procedure Client_Area_Height (Window : in out Base_Window_Type;
                              Value  : in     Natural);

function Client_Area_Height (Window : in Base_Window_Type) return Natural;

Height of window

procedure Parent (Window        : in out Base_Window_Type;
                  Parent_Window : in out Base_Window_Type'Class);

function Parent (Window : in Base_Window_Type)
                return Pointer_To_Base_Window_Class;

Parent property

function Controlling_Parent (Window : in Base_Window_Type)
                            return Pointer_To_Base_Window_Class;

Finds the first parenting window that is not a control

function Child (Window : in Base_Window_Type) return Boolean;

Returns true if window is a child of another window

function Control (Window : in Base_Window_Type) return Boolean;

Returns true if window is a control

procedure Modal_Result (Window : in out Base_Window_Type;
                        Result : in     Integer);

function Modal_Result (Window : in Base_Window_Type) return Integer;

Modal result is set automaticly by the GWindows.Events.Do_Dialog_* events

function ID (Window : in Base_Window_Type) return Integer;

Returns the ID set for the control or window at the time of creation

procedure Show (Window : in out Base_Window_Type);

Show Window

procedure Hide (Window : in out Base_Window_Type);

Hide Window

procedure Close (Window : in out Base_Window_Type);

Close and destroy Window

procedure Enable (Window : in out Base_Window_Type);

Enable window

procedure Disable (Window : in out Base_Window_Type);

Disable window

procedure Redraw (Window     : in out Base_Window_Type;
                  Erase      : in     Boolean          := False;
                  Redraw_Now : in     Boolean          := False);

Async. requests of a redraw of window

procedure Capture_Mouse (Window : in out Base_Window_Type);

Capture mouse so that all mouse messages are sent to this window

procedure Release_Mouse;

Release capture on mouse

procedure Freeze (Window : in out Base_Window_Type);

Prevents changes to the window from being drawn

procedure Thaw (Window : in out Base_Window_Type);

Allows changes to the window to be drawn

procedure Center (Window : in out Base_Window_Type);

Center window to parent

procedure Center (Window : in out Base_Window_Type;
                  Other  : in     Base_Window_Type'Class);

Center window relative to another window

procedure Move (Window : in out Base_Window_Type;
                Left   : in     Integer;
                Top    : in     Integer);

Move location of window

function Next_Tab_Stop (Window  : in Base_Window_Type;
                        Control : in Base_Window_Type'Class)
                       return Pointer_To_Base_Window_Class;

Find the next control with a tab stop after control

function Previous_Tab_Stop (Window  : in Base_Window_Type;
                            Control : in Base_Window_Type'Class)
                       return Pointer_To_Base_Window_Class;

Find the next control with a tab stop before control

type Enumerate_Function is access
  procedure (Window : Pointer_To_Base_Window_Class);

procedure Enumerate_Children (Window : Base_Window_Type;
                              Proc   : Enumerate_Function);

Enumerates through children of window calling Proc

function Point_To_Client (Window : in Base_Window_Type;
                          Point  : in GWindows.Types.Point_Type)
                         return GWindows.Types.Point_Type;

Converts a location relative to the desktop to be relative to the client area of the Window

function Point_To_Desktop (Window : in Base_Window_Type;
                           Point  : in GWindows.Types.Point_Type)
                          return GWindows.Types.Point_Type;

Converts a location relative to the client area of the Window to be relative to the desktop

procedure End_Dialog (Window : in out Base_Window_Type;
                      Result : in     Integer);

Ends a dialog or modal window and sets modal result Should be called in the On_Destroy message of any windows to be displayed as a dialog

procedure Get_Canvas (Window : in     Base_Window_Type;
                      Canvas :    out GWindows.Drawing.Canvas_Type);

Returns a canvas for drawing in the client area

procedure Get_Full_Window_Canvas
  (Window : in     Base_Window_Type;
   Canvas :    out GWindows.Drawing.Canvas_Type);

Returns a canvas for the entire window including frame, menu, etc.

type Scroll_Request_Type is (End_Scroll,
                             First,
                             Last,
                             Previous_Unit,
                             Next_Unit,
                             Previous_Page,
                             Next_Page,
                             Thumb_Set,
                             Thumb_Drag);

Base_Window_Type - Event Types

type Action_Event is access
  procedure (Window : in out GWindows.Base.Base_Window_Type'Class);

type Location_Action_Event is access
  procedure (Window : in out GWindows.Base.Base_Window_Type'Class;
             X      : in     Integer;
             Y      : in     Integer);

type Scroll_Event is access
  procedure (Window  : in out GWindows.Base.Base_Window_Type'Class;
             Request : in     Scroll_Request_Type);

type Pre_Create_Event is access
  procedure (Window    : in out GWindows.Base.Base_Window_Type'Class;
             dwStyle   : in out Interfaces.C.unsigned;
             dwExStyle : in out Interfaces.C.unsigned);

Base_Window_Type - Event Handlers

See Event Methods for details on each event

procedure On_Create_Handler (Window  : in out Base_Window_Type;
                             Handler : in Action_Event);

procedure Fire_On_Create (Window : in out Base_Window_Type);

procedure On_Pre_Create_Handler (Window  : in out Base_Window_Type;
                                 Handler : in Pre_Create_Event);

procedure Fire_On_Pre_Create (Window     : in out Base_Window_Type;
                              dwStyle    : in out Interfaces.C.unsigned;
                              dwExStyle  : in out Interfaces.C.unsigned);

procedure On_Destroy_Handler (Window  : in out Base_Window_Type;
                              Handler : in Action_Event);

procedure Fire_On_Destroy (Window : in out Base_Window_Type);

procedure On_Context_Menu_Handler (Window  : in out Base_Window_Type;
                                   Handler : in Location_Action_Event);

procedure Fire_On_Context_Menu (Window : in out Base_Window_Type;
                                X      : in     Integer;
                                Y      : in     Integer);

procedure On_Horizontal_Scroll_Handler
  (Window  : in out Base_Window_Type;
   Handler : in     Scroll_Event);

procedure Fire_On_Horizontal_Scroll
  (Window  : in out Base_Window_Type;
   Request : in     Scroll_Request_Type);

procedure On_Vertical_Scroll_Handler
  (Window  : in out Base_Window_Type;
   Handler : in     Scroll_Event);

procedure Fire_On_Vertical_Scroll
  (Window  : in out Base_Window_Type;
   Request : in     Scroll_Request_Type);

Base_Window_Type - Event Methods

When overiding events, to insure that the event handlers will still be executed when set by users, call the base class or fire the event handler directly.

procedure On_Create (Window : in out Base_Window_Type);

Called on creation of window

procedure On_Pre_Create (Window    : in out Base_Window_Type;
                         dwStyle   : in out Interfaces.C.unsigned;
                         dwExStyle : in out Interfaces.C.unsigned);

Called before creation of window to allow customizaion of the generic GWindows styles for creating a window. The GUI element of Window has not yet been created by the OS so most GUI related methods will have no effect on it.

procedure On_Destroy (Window : in out Base_Window_Type);

Called on destruction of window before deallocating Base_Window_Type

procedure On_Context_Menu (Window : in out Base_Window_Type;
                           X      : in     Integer;
                           Y      : in     Integer);

Called when the right mouse button is clicked on a window, or menu key on 102 keyboard is hit or Shift+F10 X and Y are -1 if not generated by a mouse click NOTE: Coordinates are relative to desktop

procedure On_Horizontal_Scroll
  (Window  : in out Base_Window_Type;
   Request : in     Scroll_Request_Type;
   Control : in     Pointer_To_Base_Window_Class);

Called when a horizontal scroll bar is moved If control /= null then the message will be routed down to control handler is fired only from target control/window

procedure On_Vertical_Scroll
  (Window  : in out Base_Window_Type;
   Request : in     Scroll_Request_Type;
   Control : in     Pointer_To_Base_Window_Class);

Called when a vertical scroll bar is moved If control /= null then the message will be routed down to control handler is fired only from target control/window

procedure On_Command (Window  : in out Base_Window_Type;
                      Code    : in     Integer;
                      ID      : in     Integer;
                      Control : in     Pointer_To_Base_Window_Class);

Called when a control is pushed, menu selected, or accelerator keyed Default implementation redirects message to control and if a dialog box process default buttons, ie. those with control IDs between 1 and 9

procedure On_Draw_Item
  (Window          : in out Base_Window_Type;
   Canvas          : in out GWindows.Drawing.Canvas_Type;
   Item_ID         : in     Integer;
   Item_Action     : in     Interfaces.C.unsigned;
   Item_State      : in     Interfaces.C.unsigned;
   Item_Rect       : in     GWindows.Types.Rectangle_Type;
   Item_Data       : in     Integer;
   Control         : in     Pointer_To_Base_Window_Class);

Used to support Owner Drawn items

type Notification is
   record
      Handle : GWindows.Types.Handle;
      ID     : Integer;
      Code   : Integer;
   end record;

type Pointer_To_Notification is access all Notification;

procedure On_Notify (Window       : in out Base_Window_Type;
                     Message      : in     Pointer_To_Notification;
                     Control      : in     Pointer_To_Base_Window_Class;
                     Return_Value : in out Interfaces.C.long);

On message from custom controls If control /= null then the message will be routed down to control

procedure On_Filter_Message
  (Window       : in out Base_Window_Type;
   message      : in     Interfaces.C.unsigned;
   wParam       : in     Interfaces.C.int;
   lParam       : in     Interfaces.C.int;
   Return_Value : in out Interfaces.C.long;
   Continue     : out    Boolean);

Called to allow pre processing of messages

procedure On_Message
  (Window       : in out Base_Window_Type;
   message      : in     Interfaces.C.unsigned;
   wParam       : in     Interfaces.C.int;
   lParam       : in     Interfaces.C.int;
   Return_Value : in out Interfaces.C.long);

Called for all unhandled messages

function Handle (Window : in Base_Window_Type)
                return GWindows.Types.Handle;

Win32 Handle

function Window_From_Handle (Handle : GWindows.Types.Handle)
                            return Pointer_To_Base_Window_Class;

If Handle is for a GWindows window return a pointer to the window

function MDI_Client_Window (Window : in Base_Window_Type)
                           return Base_Window_Access;

procedure MDI_Client_Window (Window      : in out Base_Window_Type;
                             Client_HWND : in     GWindows.Types.Handle);

MDI Client Window property, the MDI client window is a special window that is created inside an MDI_Top window to handle MDI child windows

function Accelerator_Handle (Window : in Base_Window_Type)
                            return GWindows.Types.Handle;

procedure Accelerator_Handle (Window : in out Base_Window_Type;
                              HACCEL : in     GWindows.Types.Handle);

Handle to accelerator table

procedure Is_Dialog (Window : in out Base_Window_Type;
                     Value  : in     Boolean);

function Is_Dialog (Window : in Base_Window_Type) return Boolean;

Returns true if window is being displayed as a dialog

procedure Is_Modal (Window : in out Base_Window_Type;
                    Value  : in     Boolean);

function Is_Modal (Window : in Base_Window_Type) return Boolean;

Returns true if window is being displayed using show_modal

procedure Attach
  (Window     : in out Base_Window_Type;
   HWND       : in     GWindows.Types.Handle;
   Is_Dynamic : in     Boolean               := False);

Attach a window created outside of GWindows to GWindows

procedure Attach_Control
  (Window     : in out Base_Window_Type;
   HWND       : in     GWindows.Types.Handle;
   Is_Dynamic : in     Boolean               := False);

Attach control created outside of GWindows to GWindows

procedure Attach_Dialog
  (Window     : in out Base_Window_Type;
   HWND       : in     GWindows.Types.Handle;
   Is_Dynamic : in     Boolean               := False);

Attachs a Created dialog to a GWindow

procedure Attach_Dialog_Item
  (Window     : in out Base_Window_Type;
   Parent     : in     Base_Window_Type'Class;
   ID         : in     Integer;
   Is_Dynamic : in     Boolean               := False);

Attach to dialog item in parent window

type Link_Type_Type is
  (Desktop_Link, Window_Link, MDI_Child_Link, Control_Link);

procedure Link
  (Window     : in out Base_Window_Type'Class;
   HWND       : in     GWindows.Types.Handle;
   Is_Dynamic : in     Boolean;
   Link_Type  : in     Link_Type_Type         := Window_Link);

Links an HWND to a Window Note: This procedure should only be used to link together windows created with Win32 windows of the "GWindows_Class"

procedure Create_Control
  (Window     : in out Base_Window_Type;
   Parent     : in out Base_Window_Type'Class;
   Win_Class  : in     GString;
   Text       : in     GString;
   Left       : in     Integer;
   Top        : in     Integer;
   Width      : in     Integer;
   Height     : in     Integer;
   ID         : in     Integer                := 0;
   Styles     : in     Interfaces.C.unsigned  := 0;
   Is_Dynamic : in     Boolean                := False);

Create a Win32 child control window Note: Win32 controls should generally be created through bindings to the various win32 controls.

function WndProc
  (hwnd    : GWindows.Types.Handle;
   message : Interfaces.C.unsigned;
   wParam  : Interfaces.C.int;
   lParam  : Interfaces.C.int)
  return Interfaces.C.long;
pragma Convention (Stdcall, WndProc);

GWindows Implementation of Win32 Procedure Call Back Procedure and Message Dispatch

function WndProc_Control
  (hwnd    : GWindows.Types.Handle;
   message : Interfaces.C.unsigned;
   wParam  : Interfaces.C.int;
   lParam  : Interfaces.C.int)
  return Interfaces.C.long;
pragma Convention (Stdcall, WndProc_Control);

GWindows Implementation of Win32 Procedure Call Back Procedure and Message Dispatch for controls

type WNDCLASS is
   record
      style         : Interfaces.C.unsigned :=
        CS_HREDRAW or CS_VREDRAW or CS_DBLCLKS or CS_OWNDC;
      lpfnWndProc   : System.Address        := WndProc'Address;
      cbClsExtra    : Interfaces.C.int      := 0;
      cbWndExtra    : Interfaces.C.int      := 0;
      hInstance     : GWindows.Types.Handle := 0;
      hIcon         : GWindows.Types.Handle := 0;
      hCursor       : GWindows.Types.Handle := 0;
      hbrBackground : GWindows.Types.Handle :=
        Interfaces.C."-" (GWindows.Colors.COLOR_BTNFACE, 1);
      lpszMenuName  : Pointer_To_GChar_C    := null;
      lpszClassName : Pointer_To_GChar_C    := null;
   end record;

Win32 WNDCLASS Structure

procedure Register_Class (Custom_Class : WNDCLASS);

Registers a custom Win32 Widnows Class. The class name can then be passed in to create procedures that accept a custom class name. Note: In order to insure that the GWindows frame work will handle messages for Windows created with your custom class, you must use either WndProc or WndProc_Control for lpfnWndProc

private

   --  Implementation-defined ...

end GWindows.Base;