Text Mode UI

Unit: TEXTUI

Text mode ($B800:0000) menu system for SETUP utility.

Constants

const
  ScreenCols = 80;
  ScreenRows = 25;

Types

type
  TMenuItemProc = procedure; {$F+}  { MUST be far call }

  TMenuItem = record
    Text: string;
    Process: TMenuItemProc;
    NextMenuItem: PMenuItem;
    Disabled: Boolean;
  end;
  PMenuItem = ^TMenuItem;

  TMenu = record
    Title: string;
    FirstMenuItem: PMenuItem;
    Col, Row, Width: Integer;
    SelectedIndex: Integer;
  end;
  PMenu = ^TMenu;

Functions

Cursor

procedure HideTextCursor;
procedure ShowTextCursor;
procedure SetTextCursorPosition(Row, Col: Byte);

Text Output

procedure PutCharAt(Col, Row: Integer; Ch: Char; Color: Byte);
procedure RenderText(Col, Row: Integer; const Text: string; Color: Byte);
procedure RenderCenterText(Row: Integer; const Text: string; Color: Byte);
procedure RenderEmptyLine(Row: Integer; Color: Byte);
function GetColumnForCenter(const Text: string): Integer;

Box Drawing

procedure RenderTextBox(Col, Row, W, H: Integer; BoxColor, ShadowColor: Byte);
procedure RenderTextBackground;

Menu System

procedure AddMenuItem(var Menu: TMenu; const Text: string; Proc: TMenuItemProc);
procedure AddEmptyMenuItem(var Menu: TMenu);
function CountMenuItems(var Menu: TMenu): Integer;
function GetMenuItem(var Menu: TMenu; Index: Integer): PMenuItem;
procedure RenderMenu(var Menu: TMenu; Index: Integer; WithBox: Boolean);
procedure FreeMenu(var Menu: TMenu);
procedure SetMenu(Menu: PMenu);
procedure StartMenu;
procedure StopMenu;

Dialog

procedure ShowMessage(const Msg, Info: string);
procedure ShowMessageNoWait(const Msg, Info: string);
function ShowInput(Col, Row, Width: Integer; const CurrentValue: string): string;

Example

uses TextUI, Crt;

procedure OnTest; {$F+}  { CRITICAL: Far call }
begin
  ShowMessage('Test', 'Button clicked!');
end;

var
  Menu: TMenu;
begin
  HideTextCursor;
  RenderTextBackground;

  FillChar(Menu, SizeOf(Menu), 0);
  Menu.Title := 'Main Menu';
  Menu.Col := 30;
  Menu.Row := 10;
  Menu.Width := 20;

  AddMenuItem(Menu, 'Test', @OnTest);
  AddMenuItem(Menu, 'Quit', nil);

  SetMenu(@Menu);
  StartMenu;  { Blocks until user selects }

  FreeMenu(Menu);
  ShowTextCursor;
end;

Color Values

0=Black    1=Blue     2=Green    3=Cyan
4=Red      5=Magenta  6=Brown    7=LightGray
8=DarkGray 9=LightBlue 10=LightGreen 11=LightCyan
12=LightRed 13=LightMagenta 14=Yellow 15=White

High nibble = background, low nibble = foreground:

Color := (BackgroundColor shl 4) or ForegroundColor;

Critical Notes

1. Far Calls: Menu callbacks MUST use {$F+} directive
2. Direct Video Memory: Writes to $B800:0000 (text mode only)
3. Arrow Keys: Up/Down navigate, Enter selects
4. StartMenu: Blocking call (returns when item selected)

Notes

• Used by SETUP utility for configuration
• Not for VGA Mode 13h (use VGAUI instead)
• Box drawing uses IBM CP437 characters (─│┌┐└┘)