TweetFollow Us on Twitter

Scroll Win in BASIC
Volume Number:2
Issue Number:1
Column Tag:Basic School

Scroll that Window in BASIC!

By Dave Kelly, General Dynamics, MacTutor Editorial Board

One of the problems of using BASIC as a programming language is the inability to access the Macintosh ROM routines. Many of the toolbox and graphics functions are built into MSBASIC (2.0 or later) such as MENU, WINDOW, EDIT FIELD, BUTTON which we have covered in prior issues of MacTutor. This month we will discover the use of some specialized LIBRARY routines which make use of Macintosh ROM routines which before this time were only accessible to other programming languages (C, Forth, 68000 Assy., and others).

Fig. 1 Basic Scrolls Windows!

The routines which are featured in this month's column come from Clear Lake Research of Houston, Texas. It should be noted that the program and discussion which follows will not work without the Clear Lake Research Libraries. Also the MacTutor source disk will contain only the listing published here and will not include any of the CLR routines used by this program listing, since they are obviously a commercial product for sale. The CLR Libraries are required to run the program. [We encourage you to obtain these routines (see ad for ordering info or watch the MacTutor mail order store for this product), since they greatly enhance the power of Microsoft Basic, which is sadly missing a majority of the toolbox capability. -Ed.]

First a few comments about library routines: In November we discussed the process of installing BASIC Libraries. Please refer to that issue for information about installing libraries. It has come to my attention that the ID numbers for some desk accessories may conflict with the resource ID numbers for libraries even though resource ID numbers of different types may have the same ID according to Inside Macintosh. The range of ID numbers should be as follows:

Range Description

-32767 through -16385 Reserved; do not use

-16384 through -1 Used for system resources owned by other system resources (see IM)

0 through 127 Used for other system resources

128 through 32767 Available for your use in whatever way you wish

Resource ID numbers for desk accessories should be between 12 and 31 inclusive. Therefore, it is advisable that the ID numbers for libraries be assigned to numbers 128 through 32767. In addition, the CLR Libraries have been assigned resource ID numbers of 10000 thru about 12000 with a few exceptions. You can be sure not to have ID numbers that don't conflict with the CLR Libraries if you use ID 20000 through 32767 for your own libraries. This applies to the _Eject routine that appeared in the November issue. I recommend that the resource ID number for the libraries be changed as explained above. The _Eject routine works fine in most cases, but there is a chance that the ID number will conflict with something else.

Please be aware of how to define variables for use in your libraries. For some reason Integer variables used in Libraries routines should be defined with a % (following the variable name) instead of using the DEFINT statement. I tried the statement, DEFINT a-z to define integers throughout the entire program and when a library routine is executed an error results. You may use DEFINT as long as the name of the variables used appear later in alphabetical order than the variables defined in the DEFINT statement. I saw no difference between BASIC 2.0 and BASIC 2.1 as far as this problem is concerned.

The demo program demonstrates the use of the CLR Libraries for implementing scroll bars within your BASIC programs. The standard Macintosh scroll bar is a predefined type of dial accessed through the Control Manager. The CLR Libraries manual (for CLR ToolLib) describes the functions which are provided for using the scroll bar to scroll text stored in an array of string variables. In summary they are:

CLR Routine Purpose

ActiveScroll: Scroll bar is made active

DisposeScroll: Scroll bar is disposed and memory is released

HideScroll: Scroll bar is made invisible

InactiveScroll: Scroll bar is made inactive

MoveScroll: Moves a scroll bar

NewScroll: Create a new scroll bar

ScrollText: Scroll text in an array of string variables

GetScrollValue: Get value of current scroll box.

SetScrollValue: Set value of current scroll box.

ShowScroll: Make scroll bar visible

SizeScroll: Set the size of the scroll bar.

The first thing to do in creating your own scroll bars is to determine what you want to scroll. Set up an array of string variables ( in the program the string is named text$ ). Next, decide size and location of the rectangle where the scrolling should take place. The array TextRect% stores the rectangle location of the area where the text will scroll. The array ScrollText% stores the rectangle indicating the size and location of the scroll bar itself. The scroll bar may be resized with the SizeScroll command if necessary. A handy routine, SetRect, is used to set up the rectangles. This saves you from having to set each variable of the rectangle array one at a time. You simply type SetRect statement, the rectangle array to define and then the (X1,Y1)-(X2-Y2) coordinates. Example:

SetRect ScrollRect%(1), 151,30,167,250

where X1=151,Y1=30, X2=167, Y2=250. Be sure to initialize any variables to be used in a library routine by setting the variable equal to zero or some other number. This reserves the variable space so that the library routine can find it when it is used by the routine. Also don't forget to define all of your array variables with DIM statements.

Scroll bars must be initially defined using the statement NewScroll. NewScroll creates a scroll bar and returns a handle. Many of the CLR Libraries use handles to point to a location in memory. In this case, the scroll bar handle points to the scroll bar to be used by the statements that follow. Don't try to print or restore a handle as the handle variable is not in a standard MSBASIC format. In the NewScroll statement you tell the routine what variable name you want to call the handle, in the program the handle is ScrollBar. The handle name is followed by the scroll rectangle array, then by a parameter indicating if the scrollbar will be visible (1=visible, 0=invisible). You may later hide or show the scroll bar with the HideScroll or ShowScroll statements. The next parameters in the NewScroll statement is the minimum value for the scroll bar indicator followed by the maximum value for the scroll bar indicator and then followed by the initial starting value of the scrollbar. Just think of the scroll box as a pointer in which the one end of the scroll bar is the minimum value and the other end is the maximum value.

The ScrollText statement is used to set the position of the scroll box. The Loop: routine in the program loops through the ScrollText statement with different values of the LineNum% and Top% (see program). Top% is used as an index of the line to appear at the top of the scrolled rectangle. If Top%=0 then the scroll bar will be redrawn. The value of LineNum% indicates the line of text which should be highlighted. When Top%=0 the scroll bar and text is redrawn and the indicated line will be highlighted. LineNum%=0 when no text is to be highlighted.

The MouseDown: routine determines if the mouse has been pressed inside the text rectangle. If it is then the line number, LineNum%, is calculated. The routine SetPt sets the Pt%(1) = MOUSE(2) and Pt%(2) = MOUSE(1). PtInRect determines if the point Pt% is in the text rectangle. The remainder of the MouseDown routine calculates the linenumber to be highlighted.

In your own program, it is the program's responsibility to determine which line of text was clicked. The Scroll Demo program will select the line of text pointed to when the cursor is selected. More possibilities could be worked out by determining when the mouse is dragged across the text rectangle. Also you should be aware of the size and style of the font being displayed in the text rectangle. The number of pixels ScrollText spaces down between lines of text is equal to the existing font's height+descent+4. The height and descent can be obtained with the GetFontInfo statement (another CLR routine). Text is always printed within the rectangle passed to the ScrollText routine. If you wish to have a border around the text rectangle, you will have to draw it yourself. The BASIC statement LINE is used in the demo program to draw a border around the text. If the window containing the scroll bar needs refreshing, the text and scroll bar will automatically be refreshed when the ScrollText statement is issued (with Top%=0 and ScrollText is issued, the text is redrawn). The border (if any) will not be automatically drawn. You should refresh the border as you would any other window needing refreshing.

To close out the scroll bar, use DisposeScroll. If your program terminates prematurely because of syntax error or by typing command-".", then you should type DisposeScroll ScrollBar, where ScrollBar is the handle to the ScrollBar. If you forget to dispose the scrollbar and forget the scrollbar handle the scrollbar will not go away without quitting BASIC. Also the memory required for the scrollbar will still be reserved and cannot be reclaimed till the scrollbar is disposed of.

Some other routines used in the program:

SortString: Sorts a string array alphabetically

Shuffle: Randomizes a string array.

ChangeCursor: Set the cursor to a cursor in the system resource file.

The usefullness of these routines and other CLR routines will be left to future articles.

'Scroll Demo
'By Dave Kelly & Clear Lake Research
'©MACTUTOR 1985
'REQUIRES CLR LIBRARIES

' This program illustrates the use of the scroll bar
' as well as a few other statements from
' CLR ToolLib and CLR MathStatLib.
' The names of 15 famous chessplayers are presented
' on the screen and can be scrolled with the scroll bar.
' The arrows as well as the scroll box are functional.
' A selected name will be highlighted.
'  The order of the names can be alphabetized or randomized.
' When the "OK button" is pressed the selected name is printed.

LIBRARY"ToolLib"
LIBRARY"MathStatLib"
OPTION BASE 1
DIM TextRect%(4),ScrollRect%(4),text$(15)
DIM Pt%(2),Index%(15),Temp$(15)
Initialize:
    ScrollBar=0
    Top%=0
    inRect%=0
    LineNum%=0
    WINDOW 1,,(60,40)-(250,330),2
    WINDOW 2,,(280,100)-(500,200),2
    TEXTFONT(0)
    LOCATE 2,9:PRINT "Professor Mac's"
    LOCATE ,9:PRINT "Scroll Bar Demo"
    TEXTFONT(3):TEXTSIZE(9)
    LOCATE ,2:PRINT "Select your favorite World Chess Champion."
    TEXTSIZE(12):TEXTFONT(0)
    WINDOW 1
    SetRect TextRect%(1),20,30,151,250
    SetRect ScrollRect%(1),151,30,167,250
    FOR i= 1 TO 15
        Index%(i)=i
    NEXT i
    BUTTON 1,1,"OK",(55,260)-(125,280)
    FOR i= 1 TO 15
        READ text$(i)
    NEXT i
    MENU 1,0,1,"Order"
    MENU 1,1,1,"Alphabetical"
    MENU 1,2,1,"Randomized"
    MENU 1,3,1,"Quit"
' clear rest of menu bar
    FOR i= 2 TO 5
        MENU i,0,1,""
    NEXT i

CreateScroll:
    LINE (20,30)-(151,249),,b
    NewScroll ScrollBar,ScrollRect%(1),1,1,10,1
    ' visible with values ranging from 1-10 startring at 1
    ' these parameters are reset by a subsequent 
    ' ScrollText statement

Loop:
ScrollText ScrollBar,TextRect%(1),text$(1),Top%,15,LineNum%
    IF MOUSE(0)<>0 THEN GOSUB MouseDown
    d%=DIALOG(0)
    IF d%=1 THEN GOSUB Buttonselected
    IF d%= 5 THEN GOSUB Update
    IF MENU(0)<> 0 THEN GOSUB MenuEvent
GOTO Loop

Buttonselected:
    WINDOW OUTPUT 2
    CLS
    TEXTFONT (0)
    LOCATE 2,4
    PRINT "Last item selected was"
    LOCATE 4,10
    IF LineNum%=0 THEN PRINT "Nothing" ELSE PRINT text$(LineNum%)
    TEXTFONT(1)
    WINDOW OUTPUT 1
    LineNum%=0:GOSUB Update
RETURN

Finish:
    DisposeScroll ScrollBar
    BUTTON CLOSE 1
    WINDOW CLOSE 2
    WINDOW 1,"Scroll Demo",(2,40)-(510,290),1
    CLS
END

Update:
Top%=0 
'That's all that's required since ScrollText will redraw the text.
    LINE (20,30)-(151,249),,b
RETURN

MouseDown:
    SetPt Pt%(1),MOUSE(1),MOUSE(2)
    PtInRect Pt%(1),TextRect%(1),inRect% 
 ' Is mousedown in TextRect?
    IF NOT inRect% THEN MouseOver
    ' IF   0<= Pt%(1) - TextRect%(1) <= 19    then LineNum%=Top%
    ' IF  20<= Pt%(1) - TextRect%(1) <= 39  then
      ' LineNum%=Top%+1      etc.
 ' The following is a fast method of calculating LineNum%
    LineNum%=(Pt%(1)-TextRect%(1))\20+Top%
      ' Make ScrollText redraw text with LineNum% selected
    Top%=0
ScrollText ScrollBar,TextRect%(1),text$(1),Top%,15,LineNum%
    
MouseOver:
    WHILE MOUSE(0)<>0:WEND 
'wait for mouse button to come up
RETURN

MenuEvent:
    ChangeCursor 4  'make cursor the watch
    ON MENU(1) GOSUB  SortIt,ScrambleIt,Finish
    MENU
    Top%=0    'so it will be redrawn
    INITCURSOR
RETURN

SortIt:
    SortString 15,text$(1)
    LineNum%=0
RETURN

ScrambleIt:
    Shuffle 15,Index%(1) 'scramble the indexes
    LineNum%=0
    FOR i= 1 TO 15
        Temp$(i)=text$(i)
    NEXT i
    FOR i= 1 TO 15
        text$(i)=Temp$(Index%(i))
    NEXT i
RETURN
DATA Morphy,Anderssen,Steinitz,Lasker,Capablanca
DATA Alekhine,Euwe,Botvinnik,Smyslov,Tal,Petrosian
DATA Spassky, Fischer,Karpov,Kasparov

Questions and Answers

Thank you to those who have sent in suggestions or questions that they may have concerning this column. MacTutor will continue to try to provide the information that you are hungry for. In response to letters received, here are the following questions/suggestions and answers:

Q. How do you tell your program to quit to the finder, instead of BASIC?

A. The command SYSTEM terminates the program and goes to the finder.

Q. A call to a sort routine is badly needed.

A. A quicksort program was printed in the Sept. MacTutor (Ask Prof. Mac column). CLR MathStat Library has various sort routines available. [Basic Smoke is also marketing both bubble and shell sort routines, string sorts with tags in assembly. Contact Jim Shores, 139 Alpine Dr., Closter, NJ 07624. Price is just $4 for each sort routine (these are in assembly for Basic). -Ed. ]

Q. Calls to clear parts of the screen would be helpful.

A. One way to clear a part of the screen is to use the GET and PUT statement to clear a section of the screen. Use PUT to read in a blank section of the desired size, then use GET to write it back whenever it is needed. Another way might be to open a window over the section to clear and then close it again without refreshing the screen.

Q. How can the defaults for the TAB function be changed while editing? As it is, one might as well use the space bar.

A. I don't know of any way to change the TAB fields.

Please continue to send in your suggestions or questions.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Ember 1.8.3 - Versatile digital scrapboo...
Ember (formerly LittleSnapper) is your digital scrapbook of things that inspire you: websites, photos, apps or other things. Just drag in images that you want to keep, organize them into relevant... Read more
Apple iTunes 12.1 - Manage your music, m...
Apple iTunes lets you organize and play digital music and video on your computer. It can automatically download new music, app, and book purchases across all your devices and computers. And it's a... Read more
LibreOffice 4.4.3 - Free, open-source of...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
FoldersSynchronizer 4.2.1 - Synchronize...
FoldersSynchronizer is a popular and useful utility that synchronizes and backs-up files, folders, disks and boot disks. On each session you can apply special options like Timers, Multiple Folders,... Read more
Simon 4.0.2 - Monitor changes and crashe...
Simon monitors websites and alerts you of crashes and changes. Select pages to monitor, choose your alert options, and customize your settings. Simon does the rest. Keep a watchful eye on your... Read more
Cocktail 8.1.2 - General maintenance and...
Cocktail is a general purpose utility for OS X that lets you clean, repair and optimize your Mac. It is a powerful digital toolset that helps hundreds of thousands of Mac users around the world get... Read more
Cyberduck 4.6.4 - FTP and SFTP browser....
Cyberduck is a robust FTP/FTP-TLS/SFTP browser for the Mac whose lack of visual clutter and cleverly intuitive features make it easy to use. Support for external editors and system technologies such... Read more
Herald 5.0.2 - Notification plugin for M...
Note: Versions 2.1.3 (for OS X 10.7), 3.0.6 (for OS X 10.8), and 4.0.8 (for OS X 10.9) are no longer supported by the developer. Herald is a notification plugin for Mail.app, Apple's Mac OS X email... Read more
DEVONthink Pro 2.8.3 - Knowledge base, i...
Save 10% with our exclusive coupon code: MACUPDATE10 DEVONthink Pro is your essential assistant for today's world, where almost everything is digital. From shopping receipts to important research... Read more
Boom 2 1.0.1 - System-wide pro audio app...
Boom 2 is a system-wide volume booster and equalizer app that is designed especially for OS X 10.10 Yosemite. It comes with a smart interface, self-calibrates itself according to your Mac, offers... Read more

Storm the Halls of Echo Base in First St...
Storm the Halls of Echo Base in First Star Wars: Galactic Defense Event Posted by Jessica Fisher on January 30th, 2015 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Contradiction Review
Contradiction Review By Tre Lawrence on January 30th, 2015 Our Rating: :: SPOT THE LIEiPad Only App - Designed for the iPad Contradiction is a live action point and click adventure that’s pretty engaging.   Developer: Tim Follin... | Read more »
Unlock Sunshine Girl in Ironkill with th...
Unlock Sunshine Girl in Ironkill with this special 148Apps code Posted by Rob Rich on January 29th, 2015 [ permalink ] Robo-fighter Ironkill has been out on iOS a | Read more »
Crossroad Zombies Review
Crossroad Zombies Review By Jordan Minor on January 29th, 2015 Our Rating: :: CROSSWALKING DEADiPad Only App - Designed for the iPad Crossroad Zombies is a rough draft of a cool genre mash-up.   | Read more »
Blood Brothers 2 – Tips, Cheats, and Str...
War is hell: Is it the kind of hell you want to check out? Read our Blood Brothers 2 review to find out! Blood Brothers 2, DeNA’s follow-up to the original Blood Brothers, is an intriguing card collecting / role-playing / strategy hybrid. There’s... | Read more »
Blood Brothers 2 Review
Blood Brothers 2 Review By Nadia Oxford on January 29th, 2015 Our Rating: :: AN AGGRAVATING RELATIVEUniversal App - Designed for iPhone and iPad Blood Brothers 2 is built on a simple, solid foundation, but its free-to-play system... | Read more »
I AM BREAD, the Toast of the Town, is Ro...
Have you ever dreamt of being deliciously gluten-y? Do you feel passionate about Rye and Wheat? The guys at Bossa Studios do and that is why they are bringing I AM BREAD to iOS soon. The loafy app will feature all the new content that is being... | Read more »
Fahrenheit: Indigo Prophecy Remastered R...
Fahrenheit: Indigo Prophecy Remastered Review By Jennifer Allen on January 29th, 2015 Our Rating: Universal App - Designed for iPhone and iPad 10 years after its initial release and Fahrenheit: Indigo Prophecy still feels like a... | Read more »
Evolve: Hunters Quest is a Match-3 That...
Evolve: Hunters Quest is a Match-3 That Has You Hunting Up Some Big Game. Posted by Jessica Fisher on January 29th, 2015 [ permalink ] | Read more »
Destructamundo Review
Destructamundo Review By Jordan Minor on January 29th, 2015 Our Rating: :: WRECKING CREWUniversal App - Designed for iPhone and iPad Destructamundo blows up real good.   | Read more »

Price Scanner via MacPrices.net

Apple Becomes World’s Largest Smartphone Vend...
According to the latest research data from Strategy Analytics, as global smartphone shipments grew 31 percent annually to reach a record 380 million units in the fourth quarter of 2014. Apple became... Read more
Cut the Cord: OtterBox Resurgence Power Case...
Dead batteries and broken phones are two of the biggest issues for smartphone users today. Otterbox addresses both with the new Resurgence Power Case for Apple iPhone 6, promising to make those panic... Read more
13-inch Retina MacBook Pros on sale for up to...
B&H Photo has 13″ Retina MacBook Pros on sale for $200 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.6GHz/128GB Retina MacBook Pro: $1199.99 save $100 - 13″ 2.6GHz/... Read more
15-inch 2.5GHz Retina MacBook Pro on sale for...
 B&H Photo has the 15″ 2.5GHz Retina MacBook Pro on sale for $2319.99 including free shipping plus NY sales tax only. Their price is $180 off MSRP, and it’s the lowest price available for this... Read more
Back in stock: Refurbished iPod nanos for $99...
The Apple Store has Apple Certified Refurbished 16GB iPod nanos available for $99 including free shipping and Apple’s standard one-year warranty. That’s $50 off the cost of new nanos. Most colors are... Read more
Apple lowers price on refurbished 256GB MacBo...
The Apple Store has lowered prices on Apple Certified Refurbished 2014 MacBook Airs with 256GB SSDs, now available for up to $200 off the cost of new models. An Apple one-year warranty is included... Read more
New Good Management Suite Simplifies Enterpri...
Good Technology has announced the availability of the Good Management Suite, a comprehensive cross-platform solution for organizations getting started with mobile business initiatives. Built on the... Read more
15-inch 2.0GHz Retina MacBook Pro (refurbishe...
The Apple Store has Apple Certified Refurbished previous-generation 15″ 2.0GHz Retina MacBook Pros available for $1489 including free shipping plus Apple’s standard one-year warranty. Their price is... Read more
15-inch 2.5GHz Retina MacBook Pro on sale for...
Amazon has the 15″ 2.5GHz Retina MacBook Pro on sale for $2319.99 including free shipping. Their price is $180 off MSRP, and it’s the lowest price available for this model from any reseller. Read more
iPad Turns Five – The ”Book Mystique
Five years ago this week, the late Steve Jobs took the stage at an Apple special press event to unveil the first Apple iPad — a slab-shaped, hand-holdable device that was to shake the personal... Read more

Jobs Board

At-Home Chat Specialist- *Apple* Online Stor...
**Job Summary** At Apple , we believe in hard work, a fun environment, and the kind of creativity and innovation that only comes about when talented people from diverse Read more
SW QA Engineer - *Apple* TV - Apple (United...
**Job Summary** The Apple TV team is looking for experienced Quality Assurance Engineers with a passion for delivering first in class home entertainment solutions. **Key Read more
*Apple* Retail - Multiple Positions(US) - Ap...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you re also the Read more
*Apple* Systems Engineer - Pre Sales, Educat...
…is responsible for proactively providing technical expertise to drive sales of Apple solutions into assigned accounts. The SE architects, validates, and assists in Read more
*Apple* Solutions Consultant - Retail Sales...
As an ambassador of the Apple brand, the ASC is accountable for driving sales performance by: Connecting with customers. Discovering customers' needs and values. Showing Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.