Microsoft KB Archive/42471

= How to Scroll Text in Separately Defined Windows in QuickBasic =

Article ID: 42471

Article Last Modified on 11/21/2006

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APPLIES TO


 * Microsoft QuickBasic 4.0
 * Microsoft QuickBASIC 4.0b
 * Microsoft QuickBasic 4.5 for MS-DOS
 * Microsoft BASIC Compiler 6.0
 * Microsoft BASIC Compiler 6.0b
 * Microsoft BASIC Professional Development System 7.0

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This article was previously published under Q42471



SUMMARY
This article describes how to use a hardware interrupt to define scrollable text windows with viewing limits on all four sides. This information applies to QuickBasic Versions 4.00, 4.00b, and 4.50, to Microsoft Basic Compiler Versions 6.00 and 6.00b, and to Microsoft Basic PDS Version 7.00 running under MS-DOS.



MORE INFORMATION
In some languages such as PASCAL, text windows are easily defined with a function called WINDOW. After a window is defined, all text written to the screen appears only within the defined window, and only text within the window is scrolled up or down. There are two additional functions, DELLINE and INSLINE, that scroll the window contents up or down one line.

Using the VIEW PRINT statements in QuickBasic, a window can be defined, but only Rows (top and bottom, ymax and ymin) can be defined. Column limits (left and right, xmin and xmax) cannot be defined. Any window defined will always use the entire width of the screen.

Defining Windows with left, right, top, and bottom limits in QuickBasic requires just a little more work, but it can be done using the CALL INTERRUPT routine with Interrupt 10 Hex, functions 06 Hex (scroll up) and 07 Hex (scroll down).

Interrupt 10 Hex, functions 06 Hex and 07 Hex, can define windows and scroll text within the defined window, but it does not prevent text from being written to other coordinates on the screen. Therefore, it is up to the programmer to write routines that will write text to the areas defined as Windows. Interrupt 10 Hex, functions 06 Hex and 07 Hex will scroll the text up or down.

Code Example
The following program demonstrates the use of Interrupt 10 Hex, functions 06 Hex and 07 Hex. Three separate Windows are defined by the following:

Window number

Window color

Window limits: left, right, top, bottom

Random text is written to each Window, scrolling the text up or down as required. '*************************************** ' Text Windowing Demonstration program. ' (Interrupt 10H, functions 06H and 07H) '*************************************** ' Define the TYPE needed for INTERRUPT (you could ' use REM $INCLUDE:'QB.BI' as an alternative under QuickBasic ' 4.00, 4.00b, 4.50 or the Basic compiler 6.00 or 6.00b. Use ' REM $INCLUDE:'QBX.BI' as an alternative under the Basic ' PDS 7.00):

TYPE RegType ax   AS INTEGER bx   AS INTEGER cx   AS INTEGER dx   AS INTEGER bp   AS INTEGER si   AS INTEGER di   AS INTEGER flags AS INTEGER END TYPE DECLARE SUB Interrupt (intnum%, inregs AS RegType, _                      outregs AS RegType) DECLARE SUB ScrollWindowUp (windowN%, numlines%) DECLARE SUB ScrollWindowDown (windowN%, numlines%) DECLARE SUB InitializeWindow (windowN%,Wcolor%,left%,_                             top%,right%,bottom%) DECLARE SUB DrawBorder (windowN%) DIM SHARED windows(5, 5) AS INTEGER     'allow max of 5 windows DIM SHARED inregs AS RegType, outregs AS RegType

CLS VIEW PRINT                          'use entire screen 25 X 80 LOCATE 25, 27 COLOR 15, 6 PRINT &quot; PRESS ANY KEY TO QUIT &quot;; InitializeWindow 1, 5, 10, 35, 3, 21              'Initialize 3 InitializeWindow 2, 2, 45, 70, 3, 11              'separate windows InitializeWindow 3, 1, 40, 70, 15, 21

DO LOCATE 22, 11 COLOR 15, windows(1, 1) FOR I% = 1 TO 26                          'print one full line of    PRINT CHR$(INT(RND * 200) + 32);         'random characters at  NEXT I%                                    'bottom of Window #1 and ScrollWindowUp 1, 1                       'Scroll Up one line

LOCATE 12, 46 COLOR 15, windows(2, 1) FOR I = 1 TO 26                           'print one full line of    PRINT CHR$(INT(RND * 200) + 32);         'random characters at  NEXT                                       'bottom of Window #2 and ScrollWindowUp 2, 1                       'Scroll Up one line

LOCATE 16, 41 COLOR 15, windows(3, 1) FOR I = 1 TO 31                           'print one full line of    PRINT CHR$(INT(RND * 200) + 32);         'random characters at  NEXT I                                     'top of Window #3 and ScrollWindowDown 3, 1                     'Scroll Down one line LOOP UNTIL INKEY$ <> &quot;&quot; END

'******************************************************************** ' SUBprogram: InitializeWindow - Interrupt 10H function 06H or 07H '            Stores the Window information for the Window specified '            in the ARRAY windows, then uses '            CALL INTERRUPT with Interrupt 10H to initialize Window ' '               AH = function 06H or 07H (scroll up or scrol down) '               AL = 00H   if zero, window is blanked '               BH = color of window '               CH = top window border '               CL = left window border '               DH = bottom window border '               DL = right window border '******************************************************************** SUB InitializeWindow(windowN%, Wcolor%, left%, right%, top%, bottom%) windows(windowN%, 1) = Wcolor% windows(windowN%, 2) = left% windows(windowN%, 3) = top% windows(windowN%, 4) = right% windows(windowN%, 5) = bottom% inregs.ax = &H600 inregs.bx = Wcolor% * 4096 inregs.cx = top% * 256 + left% inregs.dx = bottom% * 256 + right% CALL Interrupt(&H10, inregs, outregs) DrawBorder windowN% END SUB

'********************************************************** ' SUBprogram: ScrollWindowDown - Interrupt 10H function 07H ' '            AH = function 07H '            AL = number of lines to scroll '            BH = window color '            CH = top window border '            CL = left window border '            DH = bottom window border '            DL = right window border '********************************************************** SUB ScrollWindowDown (windowN%, numlines%) inregs.ax = 1792 + numlines% inregs.bx = windows(windowN%, 1) * 4096 inregs.cx = windows(windowN%, 3) * 256 + windows(windowN%, 2) inregs.dx = windows(windowN%, 5) * 256 + windows(windowN%, 4) CALL Interrupt(&H10, inregs, outregs) END SUB

'******************************************************** ' SUBprogram: ScrollWindowUp - Interrupt 10H function 06H ' '            AH = function 06H '            AL = number of lines to scroll '            BH = window color '            CH = top window border '            CL = left window border '            DH = bottom window border '            DL = right window border '******************************************************** SUB ScrollWindowUp (windowN%, numlines%) inregs.ax = 1536 + numlines% inregs.bx = windows(windowN%, 1) * 4096 inregs.cx = windows(windowN%, 3) * 256 + windows(windowN%, 2) inregs.dx = windows(windowN%, 5) * 256 + windows(windowN%, 4) CALL Interrupt(&H10, inregs, outregs) END SUB

'*********************************************** ' SUBprogram: DrawBorder '            Draws a solid border around window '            specified using character #219 '*********************************************** SUB DrawBorder (windowN%) COLOR 14, 0 FOR I% = windows(windowN%, 3) TO windows(windowN%, 5) + 2 LOCATE I%, windows(windowN%, 2) PRINT CHR$(219) LOCATE I%, windows(windowN%, 4) + 2 PRINT CHR$(219) NEXT I% FOR I% = windows(windowN%, 2) + 1 TO windows(windowN%, 4) + 1 LOCATE windows(windowN%, 3), I%   PRINT CHR$(219) LOCATE windows(windowN%, 5) + 2, I%   PRINT CHR$(219) NEXT I% END SUB

Additional query words: QuickBas BasicCom

Keywords: KB42471

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