A much better input function

This code has been declared by its author to be Public Domain code.

A much better input function by Russell

2003

Instead of examining a user's input AFTER they press enter (and then running in a loop until they press the right ones), you tell the function which keys are acceptable and ONLY accept those keys. You also specify where to put the input (no Locate required), a prompt, a default (so that if they press enter, THAT will be returned) and a maximum length.

Enjoy!
Russell

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

Comments

None.

Code Archives Forum