Text x,y,Input()

Function GetInput$(x,y,sPrompt$,sFilter$,sDefault$,iMaxLength)
   ; x = x location of the prompt, if any, or text input
   ; y = y location ...
   ; sPrompt$ is the prompt, such as "Please enter your name:"
   ; sFilter$ is very useful. It ONLY allows the user to enter certain characters. For example, "ync" would only allow "y","n" or "c"
   ;          There are also a few special 'codes':
   ;            "/all" or "" means allow anything to be entered
   ;             "/123" allows only 0 through 9 to be entered
   ;            "/abc" allows only letters of the alphabet to be entered
   
   FlushKeys
   iFlashInterval = 300      ; The blinking cursor speed
   sTotal$ = sDefault$
   iNumDigits = Len(sDefault$)
   
   If Lower$(sFilter$) = "/123" Then sFilter$ = "0123456789"               ; All the numbers
   If Lower$(sFilter$) = "/abc" Then sFilter$ = "abcdefghijklmnopqrstuvwxyz"   ; All the letters
   
   iTotalWidth = StringWidth(sPrompt$) + (iMaxLength * FontWidth())
   iTotalHeight = FontHeight()
   
   hTextBuffer = CreateImage(iTotalWidth,iTotalHeight)   ; Where the text will be drawn before blitting to the backbuffer()
   hCleanCopy = CreateImage(iTotalWidth,iTotalHeight)   ; Will hold a clean copy of the backbuffer (not the whole thing)
   MaskImage hTextBuffer,255,0,255                  ; Make the text background transparent so we can show text with BG showing
   SetBuffer ImageBuffer(hTextBuffer)               ; We're going to draw to the text buffer
   ClsColor 255,0,255                           ; Temporarily make the cls color the transparent color (magenta)
   Cls                                       ; Now clear to magenta
   ; Foreground (text) will be drawn in the current color
   
   CopyRect x,y,iTotalWidth,iTotalHeight,0,0,BackBuffer(),ImageBuffer(hCleanCopy)   ; Save a clean copy of the back buffer where the
                                                               ;    text is going to be

   SetBuffer BackBuffer()
   Repeat
      ; Blinking cursor code *******************************************************************************************************
      iCurrentTime = MilliSecs()
      If bFlash = True Then
         If (iCurrentTime - iOldFlashTime) >= iFlashInterval Then
            bFlash = False
            iOldFlashTime = MilliSecs()
         EndIf
      Else
         If (iCurrentTime - iOldFlashTime) >= iFlashInterval Then
            bFlash = True
            iOldFlashTime = MilliSecs()
         EndIf
      EndIf
      
      ; Input starts here **********************************************************************************************************
      iKeyPressed = GetKey()
      If iKeyPressed = 13 Then
         sKeyPressed$ = ""
      Else
         sKeyPressed$ = Chr$(iKeyPressed)
      EndIf
      
      ; If the key passes, add it to the total *************************************************************************************
      If iKeyPressed Then
         If (sFilter$ = "/all") Or (sFilter$ = "") Or (Instr(sFilter$,sKeyPressed$) > 0) Then ; "all" does not filter any keys out
            If Len(sTotal$) < iMaxLength Then
               sTotal$ = sTotal$ + sKeyPressed$                        ; Add it to the total string if it passes
               iNumDigits = iNumDigits + 1
            EndIf
         EndIf
      EndIf
      
      ; If backspace was pressed, delete the last character from the total and update the number of digits *************************
      If KeyDown(14) And iNumDigits > 0 Then
         sTotal$ = Left$(sTotal$,iNumDigits - 1)
         iNumDigits = iNumDigits - 1
         Delay 50
      EndIf
      
      ; Draw the clean background and then the text on the backbuffer() ************************************************************
      DrawBlock hCleanCopy,x,y

      ; Draw the cursor if enough time has passed (change iFlashInterval for different speeds) *************************************
      If Len(sTotal$) = iMaxLength Then
         rx = StringWidth(sPrompt$ + sTotal$) - StringWidth(Right$(sTotal$,1))
         rw = StringWidth(Right$(sTotal$,1))
      Else
         rx = StringWidth(sPrompt$) + (Len(sTotal$) * FontWidth())
         rw = FontWidth()
      EndIf
 
      If bFlash = True Then
         Text x,y,sPrompt$ + sTotal$
         Rect x + rx,y,rw,FontHeight(),True
      Else
         Text x,y,sPrompt$ + sTotal$
      EndIf

      Flip
   Until iKeyPressed = 13 ; This is the 'return/enter' key
   
   ClsColor 0,0,0   ; Reset back to black
   Return sTotal$
End Function