TweetFollow Us on Twitter

Events in ZBASIC
Volume Number:3
Issue Number:9
Column Tag:BASIC School

Mixing Event Manager Calls with ZBASIC

By Dave Kelly, MacTutor Editorial Board

Toolbox Event Manager from ZBASIC

Let’s explore ZBASIC from the perspective of the toolbox. At this point it should be observed that although ZBasic (version 4.0) works, it does not answer a few of our needs. Perhaps we can encourage Zedcor to add a few missing features which I will explain here.

As most of you know, programming the Macintosh in most languages involves heavy use of the toolbox routines. You might say that programming in Basic makes you soft. That’s why so many programmers move on to other languages like Pascal or C. It is easy to be lazy when the implementation of the language does most of the complex programming for you. Actually, once you know what to do, the complex stuff doesn’t seem so bad. However, because ZBasic provides statements which do a set of toolbox functions for you, your time is free to work on the organization problems of your program.

DOS versus Mac OS

In a recent discussion on the merits ( or demerits) of MS/DOS with a co-worker, my friend remarked that he thought that MS/DOS had more flexibility than the Mac operating system because the programmer could manipulate files with “powerful” statements (that he had to remember long enough to type into the computer in the correct syntax, I might add). Of course, we (as Mac programmers) all know that the power of the Mac goes beyond “powerful” statements to copy files. The Mac user interface allows “the rest of us” to cut through the mush and get to the heart of the machine. I wonder how much time has been wasted by MS/DOS users as they wade through their manual to figure out how to do something as simple as copying a file. Their time could have been used more usefully. After all, computers are supposed to make life easier, right?

Hard to Program?

The only reason I mention all this is that I feel that the Mac has taken a lot of flak about begin hard to program. Well, some have found it very difficult to program, especially when they don’t follow standard guidelines and try to write with the “look and feel” of MS/DOS on the Mac! ZBasic is different. If you want to program with toolbox calls exclusively, you can still do it. Or, if using ZBasic statements (like MENU or WINDOW) would make it easier, then use them. Maybe now that ZBasic is here the rest of the world out there might notice that it isn’t so hard to program the Mac after all.

Fig. 1 IM Sample Program in ZBasic

Some Things Require Direct Intervention

There are a few things that ZBasic does not yet support. A disk insertion event is one of them. ZBasic does mount and unmount volumes properly, but to sense the insertion of a disk requires us to create our own GETNEXTEVENT loop. The problem with this comes with the fact that if you use your own GETNEXTEVENT loop you will not be able to do any ON DIALOG or ON MENU etc. type event trapping. You will be trapping events yourself the same way that Pascal or C programmers do it. ZBasic inserts a GETNEXTEVENT statement at the beginning of every line between the ON and OFF statements (such as MENU ON or DIALOG ON). If you insert your own GETNEXTEVENT you will lose some events to the ZBasic GETNEXTEVENT statements. There may be times when you need to have precise control over where the GETNEXTEVENT is placed. Fortunately, you can do this (yes, it can and may be done), but it requires you to abandon some of the built-in capability and rely on the toolbox directly; i.e., become a “real” Mac programmer! In some ways this is better anyway. And you may still mix ZBasic statements (any that don’t trap events) along with the toolbox statements.

This month I have adapted the Sample program found at the beginning of Inside Macintosh vol 1 into a working ZBasic toolbox program. This program has revealed some interesting things about ZBasic which should be noted.

Event Manager and ZBasic

The Macintosh is event-driven. That is, the application decides what to do from moment to moment by requesting information from the Event Manager portion of the toolbox ROM through the GETNEXTEVENT statement and then responding to each event one by one in an appropriate way.

Most events are held in a queue called the event queue. The event queue normally has a capacity of 20 events. The event queue is a FIFO (first-in-first-out) buffer which holds events until they can be read from the queue.

There are several different types of events which the Event Manager will keep track of. The most important of these are

• Mouse-down, Mouse-up events;

• Key-down, Key-up events including Auto-key events which occur when the user holds down a repeating key;

• Disk inserted events;

Other important events include update and activate events which involve events which concern the Window Manager. The Event Manager always returns the highest-priority event available of the requested types.

First thing to mention is the method for setting up records of various kinds found in Inside Macintosh. The procedure is fairly painless. For example, the event record must be defined. In Pascal the event record is defined as:

TYPE EventRecord = RECORD
 what:  INTEGER; {event code}
 message: LONGINT; {event message}
 when:  LONGINT; {ticks since startup}
 where: Point;   {mouse location}
 modifiers: INTEGER; {modifier flags}
END;

Remember that Pascal integer types are 2 bytes, and longint types are 4 bytes. By declaring ZBasic’s static variables, the location of the record will be preserved where we will always know where to find it. Therefore we define the event record in ZBasic as follows:

myEvent%=0‘event code
message&=0‘event message
when&=0 ‘ticks since startup
where&=0‘mouse location
modifiers=0 ‘modifier flags

The ‘what’ variable is the same location as myEvent% as shown by the Pascal record. The other variables of the record follow sequentially in memory. That is, the next variable declared is statically defined at the next memory location. The only thing left to do is use the GETNEXTEVENT statement to see what events happen. Of course it may be harder to decide what you want to happen when the event occurs. This is where the ZBasic built-in automatic statements would have been nice to use. When GETNEXTEVENT is called, the event record will then contain the desired information regarding what, when, where and other pertinent information. Unwanted events may be screened out if desired. Maybe you only want to know when a key is pressed and don’t care about any other events.

This quick overview will never be a substitute for your own experience, but I will attempt to explain some of the ‘features’ of the Sample program.

Mixing Event Manager Calls with ZBasic

The typical ZBasic program for the Macintosh should start out with the WINDOW OFF, COORDINATE WINDOW statements and if the mouse is used any place you will probably want to use the DEF MOUSE=-1 statement. These statements turn off the default window, set the coordinate system to pixel coordinates and set up the mouse to read in a more Macintosh like mode.

The charCodeMask and keyCodeMask variables are masks we may use to mask the keyboard events to get the character and/or key code of keys pressed. It would be helpful for you to read about the Toolbox Event Manager in Inside Macintosh for a complete overview events and how to handle them.

The label “EventLoop” starts the main event loop. You may have loops within loops, even using ZBasic event statements within subroutines called from the main loop, but just keep in mind how the events will be handled. ZBasic events should definitely be confined to their own subroutines and turned off at the end of the routine.

The SELECT-CASE statement lends itself very well to the toolbox implementation of event trapping. Be careful not to exit a CASE statement with out going through the END CASE statement. For example if you try to do a RETURN from within the CASE structure you may have unpredictable results, such as system bombs??

How to Handle Variable Screen Size

I’m excited about the new Macintosh II and the possibility of larger screens and color. This will also mean that programmers must be aware that much more, of the expected uses of their program. I suppose that if you know for certain that your application is only going to be run on a 9" screen Mac then there is no problem in programming the window to open to (0,0)-(512,342). Remember that Macintosh II or other users with large screens are not going to think much of your program if it doesn’t open to full screen size.

How do I know how big the screen is? Well, the answer is not found in your ZBasic manual. The manual will help you get there, but not without some help from Inside Macintosh. In Pascal, the Quickdraw global variable, screenbits.bounds, refers to the rectangle of the screen of the Macintosh being used. But ZBasic can’t access screenbits directly because it is accessed through internal 68000 registers relative to A5. Fortunately there is another way to do it. The global variable WMgrPort (at $9DE) points to Window Manager port. [ Note: Is there a better method of finding this global variable than hard coding a memory address which could change in future memory management implementations? How about calling the toolbox window manager routine GetWmgrPort? -Ed ] The Window Manager port is a grafPort that has the entire screen as its portRect and is used by the Window Manager to draw window frames.

For those of you that don’t know what a grafPort is: a grafPort includes a bitmap to draw in, a character font, patterns for drawing and erasing, and other pen characteristics. When you open a window, a grafPort is created for that window. You may set the grafPort to the current window by using the SETPORT call. The pointer to the grafPort of the current window can be found by using the statement: GET WINDOW #1, GrafPtr&, where GrafPtr& contains the pointer. More on this is found on page E167 of the ZBasic Manual (4th edition). Also found on that same page is a description of the grafPort record (also found on page I148 of Inside Macintosh).

Notice that the 8th byte of the record contains the boundary rectangle of the image (called PortRect). The boundary rectangle of the Window Manager Port is the entire screen of whatever Macintosh the application is being run on. Therefore all that is necessary is to PEEK LONG (2 bytes) the WMgrPort pointer to see what the boundary is. Example:

WMgrPort&=PEEK LONG(&H9DE)
PortRecttop=PEEK WORD(WMgrPort&+8)
PortRectleft=PEEK WORD(WMgrPort&+10)
PortRectbottom=PEEK WORD(WMgrPort&+12)
PortRectright=PEEK WORD(WMgrPort&+14)

Now that you have the boundary you can open your window to an appropriate size, for example: (4,24)-(PortRectright-4,PortRectbottom-4) represents the rectangle the size of the entire screen minus the menu bar and a little on the sides for good looks. In the sample the variable windowrect%(0) represents the rectangle for the window opened by the program. More on GrafPorts can be found in chapter 6 (Quickdraw) and chapter 9 (Window Manager) of Inside Macintosh Vol. 1.

Toolbox Call Fixes ZBasic Bug

I found something about ZBasic type 1 windows that can be programmed around by opening your window with the NEWWINDOW toolbox function. If you use the following code instead of the NEWWINDOW method you will find that the right border of my blank window gets erased at the place where the scroll bars would be if I had any. Apparently, the window housekeeping for a type 1 window assumes or clears space for the scroll bars even if you don’t have any.

WINDOW 1,”Sample Window”,(dragleft, dragtop+20)-(dragright-4, dragbottom-4), 
257
myWindow&=WINDOW(14)

This doesn’t happen if I use NEWWINDOW to create the window. You can see this as you type in some text and look at the characters that appear at the very right edge of the window.

I’m using ZBasic version 3.85 so hopefully this minor annoyance can be remedied by Zedcor. Fortunately, there is an alternative that is compatible with ZBasic statements. Remember some of the other Basic interpreters/compilers that aren’t so lucky.

As you can see from this example and some of the past few columns of Basic School here in MacTutor we are well on our way to creating a full text editor in ZBasic. Why is this important? Because it proves Basic really can access the power of the Mac ROMs and support real Mac programs. Stay tuned for more


REM  Sample Demo (adapted from Inside Macintosh)
REM ©MacTutor 1987
REM By Dave Kelly
WINDOW OFF
COORDINATE WINDOW
DEF MOUSE=-1
everyevent=-1:REM ALL events
False=0:True=NOT False:doneflag=False
REM Setup the EventRecord
myEvent%=0:REM ‘what’ is first variable
message&=0
when&=0
where&=0
modifiers=0
applemark=&H14
whichwindow&=0
DIM Rect%(3),windowrect%(3)
charCodeMask&=VAL(“&H000000FF”)
keyCodeMask&= VAL(“&H0000FF00”)
FLUSHEVENTS
GOSUB “SetUpMenus”
WMgrPort&=PEEK LONG(&H9DE)
PortRecttop=PEEK WORD(WMgrPort&+8)
PortRectleft=PEEK WORD(WMgrPort&+10)
PortRectbottom=PEEK WORD(WMgrPort&+12)
PortRectright=PEEK WORD(WMgrPort&+14)
dragtop=PortRecttop+24
dragleft=PortRectleft+4
dragbottom=PortRectbottom-4
dragright=PortRectright-4
CALL SETRECT(windowrect%(0), dragleft, dragtop+20,       
 dragright-4, dragbottom-4)
myWindow&=FN NEWWINDOW(0,windowrect%(0), “Sample Window”, 1, 
 0,1,0,0)
CALL SETPORT(myWindow&)
CALL GETPORT(GrfPtr&)
txRect1&=PEEK LONG(GrfPtr&+16)
txRect2&=PEEK LONG(GrfPtr&+20)
CALL INSETRECT(txRect1&,4,2)
textH&=FN TENEW(txRect1&,txRect1&)

“EventLoop”: REM Main Event Loop
DO
 CALL SYSTEMTASK
 CALL TEIDLE(textH&)
 CALL SETRECT(Rect%(0),PEEK WORD (GrfPtr&+16), 
 PEEK WORD (GrfPtr&+18), PEEK WORD (GrfPtr&+20), 
 PEEK WORD (GrfPtr&+22))
 click=MOUSE(0):xpos=MOUSE(1):ypos=MOUSE(2)
 InRectangle=FN PTINRECT(xpos,Rect%(0))
 IF InRectangle THEN CURSOR 1 ELSE CURSOR 0
 LONG IF FN GETNEXTEVENT(everyevent,myEvent%)
 SELECT myEvent%
 CASE 0 :REM No Event
 CASE 1 :REM mousedown
 wResult=FN FINDWINDOW(where&,whichwindow&)
 SELECT wResult
 CASE 0 :REM inDesk (do nothing)
 CASE 1 :REM inMenuBar
 mResult&=FN MENUSELECT(where&)
 GOSUB “DoCommand”
 CASE 2 :REM inSysWindow
 CALL SYSTEMCLICK(myEvent%,whichwindow&)
 CASE 3 :REM inContent
 LONG IF whichwindow& <> FN FRONTWINDOW 
 CALL SELECTWINDOW (whichwindow&)
 XELSE
 CALL GLOBALTOLOCAL(where&)
 boolean=FN BITAND(modifiers,512)<>0
 CALL TECLICK (where&, boolean, textH&)
 END IF
 CASE 4 :REM inDrag
 LONG IF whichwindow&<>FN FRONTWINDOW
 CALL SELECTWINDOW(whichwindow&)
 XELSE
 CALL DRAGWINDOW(whichwindow&, where&, dragtop)
 END IF
 CASE 5 :REM inGrow
 CASE 6 :REM inGoAway
 END SELECT
 CASE 2 :REM mouseup
 CASE 3,5 :REM keydown or autokey
 theChar&=FN  BITAND(message&,charCodeMask&)
 LONG IF FN BITAND(modifiers,256)<>0
 mResult&=FN MENUKEY(theChar&)
 GOSUB “DoCommand”
 XELSE
 CALL TEKEY(theChar&,textH&)
 END IF
 CASE 4 :REM keyup
 CASE 6 :REM updateEvt
 CALL BEGINUPDATE(message&)
 CALL ERASERECT(txRect1&)
 CALL TEUPDATE(txRect1&,textH&)
 CALL ENDUPDATE(message&)
 CASE 7 :REM diskEvt
 CASE 8 :REM activateEvt
 LONG IF FN BITAND(modifiers,1)<>0
 CALL TEACTIVATE(textH&)
 CALL DISABLEITEM(Mhndl2&,1)
 XELSE
 CALL TEDEACTIVATE(textH&)
 CALL ENABLEITEM(Mhndl2&,1)
 END IF
 CASE 10:REM networkEvt
 CASE 11:REM driverEvt
 CASE 12:REM app1Evt
 CASE 13:REM app2Evt
 CASE 14:REM app3Evt
 CASE 15:REM app4Evt
 CASE ELSE
 END SELECT
 END IF
UNTIL doneflag
END
“SetUpMenus”
APPLE MENU “About Sample”
MENU 1,0,1,”File”
MENU 1,1,1,”Quit/Q”
Mhndl1&=FN GETMHANDLE(1)
EDIT MENU 2
Mhndl2&=FN GETMHANDLE(130)
Mhndl0&=FN GETMHANDLE(255)
RETURN
“DoCommand”
theMenu=FN HIWORD(mResult&)
theItem=FN LOWORD(mResult&)
SELECT theMenu
 CASE 255
 GOSUB “appleID”
 CASE 1
 GOSUB “fileID”
 CASE 2
 GOSUB “editID”
END SELECT
CALL HILITEMENU(0)
RETURN
“appleID”
LONG IF theItem=1
 WINDOW 5,””,(100,100)-(400,250),-2
 TEXT 0,12,0,0
 PRINT @(2,2)”Sample adapted from Inside Macintosh”
 PRINT @(10,3)”by”
 PRINT @(8,4)”Dave Kelly”
 PRINT @(6,5)”©MacTutor, 1987"
 MOUSE ON
 DO
 x=MOUSE(0)
 outsiderect=(MOUSE(1)<0 OR MOUSE(1)>300 OR MOUSE(2)<0 OR MOUSE(2)>150)
 UNTIL x<>0 AND NOT (outsiderect)
 MOUSE OFF
 WINDOW CLOSE 5
XELSE
 CALL GETITEM(Mhndl0&,theItem,Var$)
 mrefNum=FN OPENDESKACC(Var$)
 CALL SETPORT(myWindow&)
END IF
RETURN
“fileID”
doneflag=True
RETURN
“editID”
LONG IF NOT FN SYSTEMEDIT(theItem-1)
 SELECT theItem
 CASE 1:REM undo command
 CASE 3:REM cut command
 CALL TECUT(textH&)
 CASE 4:REM copy command
 CALL TECOPY(textH&)
 CASE 5:REM paste command
 CALL TEPASTE(textH&)
 CASE 6:REM clear command
 CALL TEDELETE(textH&)
 END SELECT
END IF
RETURN

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Grab it now: Game Craft’s Legend of War...
The real time strategy game is now available for you to sink your teeth into, through the App Store and Google Play. Combining elements of skill, strategy and empire building, Legend of War is a real gamers’ game. [Read more] | Read more »
Skateboard Party 3 ft. Greg Lutzka (Gam...
Skateboard Party 3 ft. Greg Lutzka 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Skateboard Party is back! This third edition of the popular sports franchise features professional skater... | Read more »
Cubious (Games)
Cubious 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: Cubious – How smart are you? How high is your IQube? Solve the impossible puzzles to find out, and help a lost little cube find his... | Read more »
Goat Simulator Waste of Space (Games)
Goat Simulator Waste of Space 1.1 Device: iOS Universal Category: Games Price: $4.99, Version: 1.1 (iTunes) Description: ** IMPORTANT - SUPPORTED DEVICESiPhone 4S, iPad 2, iPod Touch 5 or better.** | Read more »
Wildfulness - Unwind in nature and calm...
Wildfulness - Unwind in nature and calm your mind with nature sounds and illustrations 1.0 Device: iOS Universal Category: Healthcare & Fitness Price: $1.99, Version: 1.0 (iTunes) Description: Spending time in nature helps you to... | Read more »
Dr. Panda Racers (Education)
Dr. Panda Racers 1.0 Device: iOS Universal Category: Education Price: $2.99, Version: 1.0 (iTunes) Description: STEP ON THE GAS, RACE AND WIN!Fasten your seat belts and get ready to race! Speed your way to the finish line while doing... | Read more »
ROMANCING SAGA 2 (Games)
ROMANCING SAGA 2 1.0.0 Device: iOS Universal Category: Games Price: $17.99, Version: 1.0.0 (iTunes) Description: Romancing SaGa 2, originally released only in Japan in 1993, has been completely remastered and now receives its first... | Read more »
WRIO Keyboard (Utilities)
WRIO Keyboard 1.0 Device: iOS iPhone Category: Utilities Price: $2.99, Version: 1.0 (iTunes) Description: 40% OFF DURING LIMITED INTRODUCTORY OFFER | Read more »
Hatoful Boyfriend (Games)
Hatoful Boyfriend 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: The hit PC game that everybirdie loves has now migrated to your mobile device! Now you are free to explore the wonders of St... | Read more »
Warp Shift (Games)
Warp Shift 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: [ CHECK YOUR HARDWARE: Warp Shift does NOT run on iPhone 4, iPad 1 and iPod touch 4G or older devices! It requires at least iOS8... | Read more »

Price Scanner via MacPrices.net

Goal Zero and OtterBox Partner to Expand iPh...
Goal Zero, specialists in portable power, have announced a partnership with OtterBox, brand smartphone case protection, to offer the Slide and Slide Plus Batteries as modules compatible with the new... Read more
15-inch Retina MacBook Pros on sale for up to...
B&H Photo has 15″ Retina MacBook Pros on sale for up to $210 off MSRP. Shipping is free, and B&H charges NY tax only: - 15″ 2.2GHz Retina MacBook Pro: $1799 $200 off MSRP - 15″ 2.5GHz Retina... Read more
Clearance 2015 13-inch MacBook Airs available...
B&H Photo has clearance 2015 13″ MacBook Airs available for $250 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 1.6GHz/4GB/128GB MacBook Air (MJVE2LL/A): $799... Read more
Apple refurbished Apple TVs available for up...
Apple has Certified Refurbished 32GB and 64GB Apple TVs available for up to $30 off the cost of new models. Apple’s standard one-year warranty is included with each model, and shipping is free: -... Read more
21-inch iMacs on sale for up to $120 off MSRP
B&H Photo has 21″ iMacs on sale for up to $120 off MSRP including free shipping plus NY sales tax only: - 21″ 3.1GHz iMac 4K: $1379.99 $120 off MSRP - 21″ 2.8GHz iMac: $1189 $110 off MSRP - 21″ 1... Read more
Kanex Introduces GoPower USB-C Rechargeable B...
Kanex has announced its GoPower USB-C portable battery for the USB-C MacBook, featuring the new industry standard connector and cable used for connectivity and power. Providing users with a new... Read more
Convertible and Detachable Devices Winning Ov...
According to the latest figures published by International Data Corporation (IDC), Western European shipments of ultraslim convertibles and detachables posted positive growth (44.7%) to account for... Read more
New MacBook Pros And Will MacBook Air Be Upgr...
With my mid-2013 13-inch MacBook Air closing on its third anniversary come November, I’m in system upgrade mode. Actually the Haswell CPU equipped Air is still doing a fine job, but my good wife is... Read more
Apple’s Education discount saves up to $300 o...
Purchase a new Mac or iPad using Apple’s Education Store and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free, and... Read more
13-inch 2.5GHz MacBook Pro on sale for $999,...
B&H Photo has the 13″ 2.5GHz MacBook Pro on sale for $999 including free shipping plus NY sales tax only. Their price is $100 off MSRP. Read more

Jobs Board

Service Assistant - *Apple* Chevrolet *App...
Apple Automotive is one of the fastest growing dealer...and it shows. Consider making the switch to the Apple Automotive Group today! At Apple Automotive, we Read more
Editor, *Apple* News - APPLE (United States...
Job Summary The Apple News team is looking for a passionate and knowledgeable editor with experience covering entertainment/pop culture and experience running social Read more
*Apple* Nissan Service Technicians - Apple A...
Apple Automotive is one of the fastest growing dealer...and it shows. Consider making the switch to the Apple Automotive Group today! At Apple Automotive , Read more
ISCS *Apple* ID Site Support Engineer - APP...
…position, we are looking for an individual who has experience supporting customers with Apple ID issues and enjoys this area of support. This person should be Read more
Automotive Sales Consultant - Apple Ford Linc...
…you. The best candidates are smart, technologically savvy and are customer focused. Apple Ford Lincoln Apple Valley is different, because: $30,000 annual salary Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.