' MOUSTEST.BAS    : shows how to implement the mouse in a program
' Author          : Egbert Zijlema (E.Zijlema@uni4nn.iaf.nl)
' Date            : July 23, 1996
' Language        : Power Basic 3.2
' Copyright status: Public Domain

' Introduction:
' Routines concerning the status of the mouse are basically very simple.
' They are all done by calling INTERRUPT &H33. Depending of the value
' passed through the AX-register one can test the presence of the mouse
' driver, show/hide the mouse cursor, define a limited screen area,
' and so forth.
' But unfortunately all those well known routines don't tell you how to
' implement the mouse in your program. How, for instance, do you tell
' your software that clicking on the word "File" in the menu bar means
' the same as pressing Alt-f (to pull down the File menu)?
' This demo shows how to select a file from a list of 24 filenames
' either by the mouse or the arrow keys.

' Credit:
' The INTERRUPT-routines, written in assembly, are from Dave Navarro.
' They came with Power Basic 3.2 (MOUSUNIT.BAS in the EXAMPLE
' subdirectory). I took the liberty to add 2 'flags' to those routines,
' one for the presence of the driver and one for the hide/show status of
' the cursor. The benefit of the first is obvious: you only need 1 test
' for the presence of the mousedriver. The purpose of the second is
' to avoid switching on/off the cursor more than once. This is rather
' crucial, due to the fact that the mouse is counting, not toggling, its
' on/off status. If you accidently should hide the mouse twice, you MUST
' also do the opposite twice in order to make it visible again.

DEFINT A - Z

TYPE MOUSEFLAGS
  mouse AS INTEGER                                ' mouse driver present
  mseon AS INTEGER                                ' mouse cursor on/off
END TYPE

DIM mflg AS SHARED MOUSEFLAGS
DIM VideoAddress AS SHARED INTEGER
DIM FileName(1 : 24) AS SHARED STRING

IF (pbvScrnCard AND 1) = 0 THEN
  VideoAddress = &HB800                           ' color card
ELSE
  VideoAddress = &HB000                           ' monochrome
END IF

IF MsThere THEN
  mflg.mouse = -1                                 ' mouse driver present
  DIM matrix(1 : 25, 1 : 80) AS SHARED INTEGER    ' screen matrix 2000 cells
END IF

' equates for arrow keys:
%HOME  = 71 * 256 : %UP  = 72 * 256 : %LEFT = 75 * 256
%RIGHT = 77 * 256 : %END = 79 * 256 : %DOWN = 80 * 256

FUNCTION MsThere AS INTEGER
  ! push DS                 ; save DS for PowerBASIC
  ! xor  AX, AX             ; clear AX
  ! int  &H33               ; call mouse driver
  ! xor  BX, BX             ; clear BX, assume no mouse present

  ! or   AX, AX             ; does AX = 0?
  ! jz   MsThereDone        ; yes, we're done
  ! dec  BX                 ; no, make it -1
MsThereDone:
  ! mov  FUNCTION, BX       ; put BX in RetVal variable
  ! pop  DS                 ; restore DS
END FUNCTION

FUNCTION GetMouseOrKey
  STATIC oldKey
  MsStatus oldButn, dummy, dummy
  DO
    MsStatus buttons, row, col

    IF INSTAT THEN
      oldKey = CVI( INKEY$ + CHR$(0) )
      FUNCTION = oldKey
      EXIT FUNCTION
    ELSEIF (buttons = 1) AND (matrix(row, col) <> oldKey) THEN
      oldKey   = matrix(row, col)
      FUNCTION = oldKey
      EXIT FUNCTION
    END IF

    LOOP UNTIL (oldButn = 1) AND (buttons = 0)
    oldKey = 13 : FUNCTION = 13
END FUNCTION

SUB MsCursorOn
  IF NOT mflg.mouse THEN EXIT SUB                 ' no mouse, so quit
  IF NOT mflg.mseon THEN                          ' only if mouse off
    ! push DS                  ; save DS for PowerBASIC
    ! mov  AX, 1               ; mouse driver function 1, turn on cursor
    ! int  &H33                ; call driver
    ! pop  DS                  ; restore DS
    mflg.mseon = -1                               ' mouse cursor on
  END IF
END SUB

SUB MsCursorOff
  IF NOT mflg.mouse THEN EXIT SUB
  IF mflg.mseon THEN
    ! push DS                  ; save DS for PowerBASIC
    ! mov  AX, 2               ; mouse driver function 2, turn off cursor
    ! int  &H33                ; call driver
    ! pop  DS                  ; restore DS
    mflg.mseon = 0                                ' mouse cursor off
  END IF
END SUB

SUB MsStatus(buttons AS INTEGER, row AS INTEGER, col AS INTEGER)
  IF NOT mflg.mouse THEN EXIT SUB
  ! push DS                  ; save DS for PowerBASIC
  ! mov  AX, &H03            ; function 03h, get mouse status
  ! int  &H33                ; call mouse interrupt
  ! les  DI, buttons         ; point ES:DI to buttons
  ! mov  ES:[DI], BX         ; put active button(s) in variable
  ! les  DI, row             ; point ES:DI to Row
  ! mov  ES:[DI], DX         ; put mouse row in variable
  ! les  DI, col             ; point ES:DI to Column
  ! mov  ES:[DI], CX         ; put mouse column in variable
  ! pop  DS                  ; restore DS for PowerBASIC

  IF (pbvScrnMode = 7) OR (pbvScrnMode = 0) THEN
    row = (row \ 8) + 1      ' if text mode, then fix coordinates
    col = (col \ 8) + 1
  END IF
END SUB

SUB MsSetWindow(BYVAL Row  AS INTEGER, BYVAL Col  AS INTEGER, _
                BYVAL Rows AS INTEGER, BYVAL Cols AS INTEGER)

  IF NOT mflg.mouse THEN EXIT SUB
  Rows = Row + Rows - 1      ' adjust rows to real coordinates
  Cols = Col + Cols - 1      ' adjust cols to real coordinates

  IF (pbvScrnMode = 7) OR (pbvScrnMode = 0) THEN
    Row  = Row  * 8          ' if text mode, adjust coordinates
    Rows = Rows * 8
    Col  = Col  * 8
    Cols = Cols * 8
  END IF

  ! push DS                  ; save DS for PowerBASIC
  ! mov  CX, Row             ; put start row in CX
  ! mov  DX, Rows            ; put end row in DX
  ! mov  AX, &H08            ; function 08h, set vertical limit
  ! int  &H33                ; call mouse interrupt
  ! mov  CX, Col             ; put start column in CX
  ! mov  DX, Cols            ; put end column in DX
  ! mov  AX, &H07            ; function 07h, set horizontal limit
  ! int  &H33                ; call mouse interrupt
  ! pop  DS                  ; restore DS for PowerBASIC
END SUB

SUB CollectFileNames
  SHARED PrimaryScreen$
  FileToFind$ = DIR$("C:\DOS\*.*")
  DO WHILE LEN(FileToFind$)
    INCR count
    FileName(count) = FileToFind$
    IF count = UBOUND(FileName) THEN EXIT DO      ' no more than 24 names
    FileToFind$ = DIR$
  LOOP

  ' and display them
  COLOR 15, 0
  row = 2 : col = 4
  FOR count = 1 TO UBOUND(FileName)
    LOCATE row, col
    PRINT FileName(count)

    FOR cell = col TO col + LEN(FileName(count)) - 1
      matrix(row, cell) = count + 256             ' don't use ASCII!
    NEXT

    INCR col, 14
    IF col = 60 THEN
      INCR row : col = 4
    END IF
  NEXT

  ' finally save the screen
  DEF SEG = VideoAddress
  PrimaryScreen$ = PEEK$(0, 4000)
  DEF SEG
END SUB

SUB SelectionMenu
  SHARED PrimaryScreen$
  STATIC selected
  IF selected = 0 THEN selected = 1
  GOSUB inverse
  DO
    MsSetWindow 1, 3, 6, 54
    MsCursorOn
    modified = 0
    action = GetMouseOrKey
    SELECT CASE action
      CASE 27
        selected = 0
        EXIT LOOP
      CASE %LEFT
        IF selected > 1 THEN
          DECR selected
          modified = -1
        END IF
      CASE %RIGHT
        IF selected < UBOUND(FileName) THEN
          INCR selected
          modified = -1
        END IF
      CASE %HOME
        IF selected > 1 THEN
          selected = 1
          modified = -1
        END IF
      CASE %END
        IF selected < UBOUND(FileName) THEN
          selected = UBOUND(FileName)
          modified = -1
        END IF
      CASE %UP
        IF selected > 4 THEN
          DECR selected, 4
          modified = -1
        END IF
      CASE %DOWN
        IF selected < UBOUND(FileName) - 3 THEN
          INCR selected, 4
          modified = -1
        END IF
      CASE 257 TO UBOUND(FileName) + 256
        selected = action - 256
        modified = -1
    END SELECT
    IF modified THEN GOSUB inverse
  LOOP UNTIL action = 13                          ' until ENTER is pressed
  MsCursorOff
  DEF SEG = VideoAddress
  POKE$ 0, PrimaryScreen$
  DEF SEG
  COLOR 15, 0
  LOCATE 25,4
  PRINT "You selected ";
  IF selected = 0 THEN
    PRINT "nothing";
  ELSE
    PRINT CHR$(34);FileName(selected);CHR$(34);
  END IF
  EXIT SUB

inverse:
  MsCursorOff
  DEF SEG = VideoAddress
  POKE$ 0, PrimaryScreen$
  DEF SEG
  factor = selected - 1
  hor  = 2 + factor \ 4
  vert = 4 + (factor MOD 4) * 14
  COLOR 0, 7
  LOCATE hor, vert : PRINT FileName(selected)
  RETURN
END SUB

SUB MainMenu
  DO
    COLOR 7, 0
    LOCATE 20, 4 : PRINT "Press any arrow key to select; ESC to quit"
    KeyIn = GetMouseOrKey
    SELECT CASE KeyIn
      CASE 27                                     ' Escape pressed
        COLOR 7, 0
        CLS
        SYSTEM
      CASE %RIGHT, %LEFT, %UP, %DOWN              ' any arrow key
        COLOR 7, 0
        LOCATE 25, 1 : PRINT SPACE$(80);
        CALL SelectionMenu
    END SELECT
  LOOP
END SUB

' sample main
CLS
  CollectFileNames
  MainMenu
END