TweetFollow Us on Twitter

Updating Windows
Volume Number:4
Issue Number:3
Column Tag:Basic School

Updating Windows in Basic

By Dave Kelly, MacTutor Editorial Board

Dave Kelly is an electrical engineer for General Dynamics in Pomona, where he is involved in using work stations for hardware design. He is a founding editorial board member and currently an active board member for MacTutor.

A fresh window lets you see things more clearly. (I like mine in color, but black & white mode on the Macintosh II sure is faster). I received the following request from one of our readers which I’m sure others of you would also like to know about:

Q. I am working on an application in ZBasic 4.00 that I hope to release commercially. Previously I never had to worry about handling update events in a “correct” manner (in the past I have always reprinted everything on the screen when I’ve encountered an update event). ZBasic does provide a WINDOW PICTURE statement that I have not gotten to work to my satisfaction. I have also tried GET and PUT without much success. I’m obviously doing something wrong. could you show various ways to handle update events that involve DAs and multiple windows? My application has Edit Fields and displayed text (i.e. displaying results obtained from values entered in the edit fields).

A. Yes, there can be some tricky problems associated with refreshing windows which use edit fields. There is a standard way that refreshing should work. In Pascal the application should respond by calling BeginUpdate, drawing the window, then call EndUpdate. The Window Manager section of Inside Macintosh explains how to do this. That’s fine when using the Macintosh standard GetNextEvent loop, but in ZBasic the approach must be modified.

The object is to restore any window which gets covered up by another window. If window 1 is dragged over window 2, then if window 2 is selected it should automatically be redrawn. Or if only part of window 2 is covered up and window 1 is removed then window 2 should be refreshed. This means that you as a programmer are responsible to determine all of the possible ways the window could be erased and be sure to set up event handling to cover all the possibilities.

There are 3 options we have for screen refresh with ZBasic.

1. Redraw the picture in response to a DIALOG event.

2. Use the WINDOW PICTURE statement.

3. Use GET and PUT in response to a DIALOG event.

By the end of this discussion you will know when to use each method in different circumstances. Directly redrawing the window is probably used most often by those that don’t know about the other two methods (or don’t know how they work). Redrawing is what I think of as the “brute force” method. It is usually the method used for “quick and dirty” screen refresh. The advantage is that you have control to force the update to occur whenever you feel like it. The disadvantage is that it is slower and you may find that the screen may get updated sometimes when it doesn’t need it (in order to catch every possible event).

Fig. 1 Our Multiple Window Example

To refresh by redrawing in the “brute force” mode a DIALOG(0)=5 event should effectively determine when a window needs to be refreshed. The window that needs to be refreshed is returned in the DIALOG(5) function. A quick call to the screen drawing routine when DIALOG event occurs is all that is needed to make this work.

The 2nd method of refreshing the screen is somewhat unique to ZBasic. Using the WINDOW PICTURE statement is the most automatic way to update the screen. A good example of using WINDOW PICTURE is given in the ZBasic manual on page E-158. The example at the end of this column also demonstrates its use. There are a few problems which you should be aware of. When using WINDOW PICTURE, all DIALOG events for the window involved are not passed to the DIALOG function, but instead are automatically handled by the WINDOW PICTURE statement. This is both good and bad. It is good because now any portion of the screen can be refreshed automatically without really trying. The problem comes when you use an EDIT FIELD in the window which you are using WINDOW PICTURE. When WINDOW PICTURE is active, the EDIT FIELD is not updated properly. Ordinarily the EDIT FIELD is automatically updated, but not with WINDOW PICTURE. This is one of those cases where the window should be refreshed with the “brute force” method. The process can be improved by setting up the screen information to be updated in a PICTURE so that it can be redrawn quickly. The demo shows how this is done. The “Set Window 1 Update” routine is called whenever an update event occurs. Also the EDIT FIELD value is re-read and the text displayed is obtained from the current contents of the EDIT FIELD. It is really too bad that in ZBasic the WINDOW PICTURE statement doesn’t update controls. [My guess is that WINDOW PICTURE is nothing more than the automatic window updating procedure of placing a quickdraw picture handle in the window record’s pic field, in which case, no controls or edit fields would be updated. This method was only intended for fairly static window contents, and never meant to be a true update procedure for dynamic windows. -Ed]

To use WINDOW PICTURE you first define the PICTURE which you want to print. This can be a combination of text and graphics. The PICTURE is pointed to by a variable which is used in the WINDOW PICTURE statement to initialize the automatic update routine. To stop the update or to modify it you can use WINDOW PICTURE #1,0 (if using window #1) and then KILL PICTURE to delete the picture from memory. If you don’t remove the pictures from memory, they may use up some of your memory and sooner or later if enough pictures are used, you could run out of memory.

I think the 3rd method is a bit more cumbersome than the first two. I call it the “GET/PUT” method. First, the window contents are drawn for the first time. Then the rectangle containing the contents of the window must be determined exactly. These coordinates are plugged in to an equation given on page 232 of the ZBasic manual. The equation determines the number of bytes to use in a DIM statement for the graphic image used in the GET and PUT statement. The equation is:

bytes = 6 + ((y2-y1)+1) * ((x2-x1)+1) * bpp + 7) / 8

where x1, y1 are the coordinates of the upper-left-corner of the graphic image on the screen; x2, y2 are the coordinates of the lower-right-corner of the image. The bits-per-pixel, bpp, depends on your Macintosh screen setup. Standard black & white Macintoshes have one bit per pixel, a Macintosh II with sixteen colors is 4 bpp and 256 colors is 8 bpp. Now divide the number of bytes by two for the integer (16 bit) array used in the DIM statement. This is the extent of the difficulty in using the “GET/PUT” method. The DIM statement should be executed only once at the beginning of your program and enough space should be allocated for whatever you plan to update. After the screen is drawn the first time, the GET statement is used to set the array to the screen image. If your array isn’t dimensioned big enough you can definitely expect a system bomb here. I would recommend that you only use the “GET/PUT” method when you are not going to change the window contents. The PUT statement is called by the DIALOG event routine whenever the window needs refreshing. (Mac II color users, notice that the PUT statement only refreshes in black & white; the color information is ignored. This is unfortunate. Maybe in a future release of ZBasic with 256 color support?????).

The demo program demonstrates the three methods discussed above. Try opening DAs and dragging a window on top of other windows and closing/opening them. I feel that this program should give you a good idea of how windows can be refreshed. I strongly recommend that most of your refreshing be done with the WINDOW PICTURE statement whenever possible. (NOTE: ‘whenever possible’ is just about always, except when controls are used on the same screen. Maybe this will get fixed someday too so that WINDOW PICTURE will work when EDIT FIELDs are active).

This has been a much more pleasant program to write as Zedcor has released version 4.01 with a much improved editor. The editor isn’t perfect, but if you remember to save your program often enough you can get by without exiting ZBasic. Also, they have added DIALOG(0)=17 for disk inserts. DIALOG(17) returns the disk drive which the disk was inserted. ZBasic is still the best Basic available today and keeps looking better each new release. Zedcor, keep up the good work.

Zedcor and True Basic have announced new versions at the San Francisco Expo. Watch for details on these new products. -Ed

‘ WINDOW UPDATE DEMO
‘ ©1988 MacTutor®
‘ By Dave Kelly

WINDOW OFF
COORDINATE WINDOW
DEF MOUSE=-1
DIM Wptr&(3)

APPLE MENU “About Updating ”
MENU 1,0,1,”File”
MENU 1,1,1,”Quit”
EDIT MENU 2
MENU 3,0,1,”Window”
MENU 3,1,1,”Show Window 1"
MENU 3,2,1,”Show Window 2"
MENU 3,3,1,”Show Window 3"
MENU 3,4,1,”Show All Windows”

‘Find out monitor size just in case we need it
CALL GETWMGRPORT(WMgrPort&)
PortTop=PEEK WORD(WMgrPort&+8)
PortLeft=PEEK WORD(WMgrPort&+10)
PortBottom=PEEK WORD(WMgrPort&+12)
PortRight=PEEK WORD(WMgrPort&+14)

WINDOW#1,”Window 1",(PortLeft+4,PortTop+42)-(300,300),5
Wptr&(1)=WINDOW(14)
TEXT 3,12
EDIT FIELD 1,”Read MacTutor!”,(50,200)-(270,225),1
GOSUB “Set Window 1 Update”

WINDOW#2,”Window 2",(PortLeft+24,PortTop+62)-(320,320),5
Wptr&(2)=WINDOW(14)
‘NOW... Create the picture for the first window
PICTURE ON
TEXT 2,24,1
COLOR=4
PRINT@(3,1)”MacTutor®”
COLOR=7
TEXT 3,12,0
PRINT@(6,4)”The Best in the West!”
PRINT@(5,6)”This is the second window”
PICTURE OFF,Pic2&
PICTURE, Pic2&:’ Draw the picture
WINDOW PICTURE #2,Pic2&

WINDOW#3,”Window 3",(PortLeft+44,PortTop+82)-(340,340),5
Wptr&(3)=WINDOW(14)
x1=0:x2=300:y1=0:y2=300
‘ bytes used = 6 + ((y2-y1)+1) * ((x2-x1+1)* bpp + 7) / 8)
DIM Pic3%(58293) :’ space for 32 bits-per-pixel (MAC II)
‘ NOW... Create the picture for the third window
TEXT 2,24,1
COLOR=4
PRINT@(3,1)”MacTutor®”
COLOR=7
TEXT 3,12,0
PRINT@(6,4)”The Best in the West!”
PRINT@(5,6)”This is the third window”
GET (x1,y1)-(x2,y2),Pic3%(1)
PUT (0,0),Pic3%(1),0

ON DIALOG GOSUB “DialogEvent”
ON MENU GOSUB “MenuEvent”
FLUSHEVENTS
MENU ON:DIALOG ON

“Loop”
GOTO “Loop”
MENU OFF:DIALOG OFF

“DialogEvent”
D=DIALOG(0)
SELECT D
 CASE 3
 WINDOW DIALOG(3)
 CASE 4
 CALL HIDEWINDOW(Wptr&(DIALOG(4)))
 CASE 5,6,7
 IF DIALOG(5)=3 THEN GOSUB”Window3 Update” ELSE GOSUB “Set Window 1 Update”
END SELECT
RETURN

“MenuEvent”
Menunumber=MENU(0)
Menuitem=MENU(1)
MENU
SELECT Menunumber
 CASE 255
 GOSUB “AppleMenu”
 CASE 1
 GOSUB “FileMenu”
 CASE 3
 GOSUB “WindowMenu”
END SELECT
RETURN

“AppleMenu”
WINDOW 4,””,(100,100)-(400,250),-2
PICTURE ON
TEXT 0,12,0,0
PRINT @(2,2) “(ZBASIC) Window Update Demo V1.0”
PRINT @(10,3)”by”
PRINT @(8,4)”Dave Kelly”
COLOR=6
PRINT @(7,6)”©MacTutor, 1988"
COLOR=7
PRINT @(7,7)”ZBasic version 4.01"
PICTURE OFF,Pic4&
PICTURE ,Pic4&
WINDOW PICTURE #4,Pic4&
MOUSE ON
DO
mous=MOUSE(0)
outsiderect=(MOUSE(1)<0 OR MOUSE(1)>300 OR MOUSE(2)<0 OR MOUSE(2)>150)
IF MOUSE(1)=0 AND MOUSE(2)=0 THEN “Stop”
UNTIL mous<>0 AND NOT (outsiderect)
MOUSE OFF
KILL PICTURE Pic4&:’ Delete the picture from memory
DIALOG ON
WINDOW CLOSE 4
DIALOG OFF
RETURN

“Window3 Update”
ActiveWindow=WINDOW(0)
WINDOW OUTPUT 3
PUT (0,0),Pic3%(1),0
WINDOW OUTPUT ActiveWindow
RETURN

“Set Window 1 Update”
ActiveWindow=WINDOW(0)
WINDOW OUTPUT 1
‘NOW... Create the picture for the first window
 KILL PICTURE Pic1&
 PICTURE ON
 TEXT 2,24,1
 COLOR=4
 PRINT@(3,1)”MacTutor®”
 COLOR=7
 TEXT 3,12,0,0
 PRINT@(6,4)”The Best in the West!”
 PRINT@(5,6)”This is the first window”
 Editvariable$=EDIT$(1)
 PRINT@(5,8)”The edit field = “;Editvariable$
 PICTURE OFF,Pic1&
PRINT@(5,8);SPC(100)
PICTURE, Pic1&:’ Draw the picture
WINDOW OUTPUT ActiveWindow
RETURN

“FileMenu”
IF Menuitem=1 THEN “Stop”
RETURN

“WindowMenu”
SELECT Menuitem
 CASE 1
 CALL SHOWWINDOW(Wptr&(1)):WINDOW 1
 CASE 2
 CALL SHOWWINDOW(Wptr&(2)):WINDOW 2
 CASE 3
 CALL SHOWWINDOW(Wptr&(3)):WINDOW 3
 CASE 4
 FOR i=1 TO 3
 CALL SHOWWINDOW(Wptr&(i))
 WINDOW i
 NEXT i
END SELECT
RETURN

“Stop”
WINDOW PICTURE #1,0:’Don’t update the first window anymore
KILL PICTURE Pic1&:’ Delete the picture from memory
WINDOW PICTURE #2,0:’Don’t update the second window anymore
KILL PICTURE Pic2&:’ Delete the picture from memory
END
 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Duplicate Annihilator 5.7.5 - Find and d...
Duplicate Annihilator takes on the time-consuming task of comparing the images in your iPhoto library using effective algorithms to make sure that no duplicate escapes. Duplicate Annihilator... Read more
BusyContacts 1.0.2 - Fast, efficient con...
BusyContacts is a contact manager for OS X that makes creating, finding, and managing contacts faster and more efficient. It brings to contact management the same power, flexibility, and sharing... Read more
Capture One Pro 8.2.0.82 - RAW workflow...
Capture One Pro 8 is a professional RAW converter offering you ultimate image quality with accurate colors and incredible detail from more than 300 high-end cameras -- straight out of the box. It... Read more
Backblaze 4.0.0.872 - Online backup serv...
Backblaze is an online backup service designed from the ground-up for the Mac.With unlimited storage available for $5 per month, as well as a free 15-day trial, peace of mind is within reach with... Read more
Little Snitch 3.5.2 - Alerts you about o...
Little Snitch gives you control over your private outgoing data. Track background activity As soon as your computer connects to the Internet, applications often have permission to send any... Read more
Monolingual 1.6.4 - Remove unwanted OS X...
Monolingual is a program for removing unnecesary language resources from OS X, in order to reclaim several hundred megabytes of disk space. If you use your computer in only one (human) language, you... Read more
CleanApp 5.0 - Application deinstaller a...
CleanApp is an application deinstaller and archiver.... Your hard drive gets fuller day by day, but do you know why? CleanApp 5 provides you with insights how to reclaim disk space. There are... Read more
Fantastical 2.0 - Create calendar events...
Fantastical is the Mac calendar you'll actually enjoy using. Creating an event with Fantastical is quick, easy, and fun: Open Fantastical with a single click or keystroke Type in your event details... Read more
Cocktail 8.2 - General maintenance and o...
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
Direct Mail 4.0.4 - Create and send grea...
Direct Mail is an easy-to-use, fully-featured email marketing app purpose-built for OS X. It lets you create and send great looking email campaigns. Start your newsletter by selecting from a gallery... Read more

Fast & Furious: Legacy's Creati...
| Read more »
N-Fusion and 505's Ember is Totally...
| Read more »
These are All the Apple Watch Apps and G...
The Apple Watch is less than a month from hitting store shelves, and once you get your hands on it you're probably going to want some apps and games to install. Fear not! We've compiled a list of all the Apple Watch apps and games we've been able to... | Read more »
Appy to Have Known You - Lee Hamlet Look...
Being at 148Apps these past 2 years has been an awesome experience that has taught me a great deal, and working with such a great team has been a privilege. Thank you to Rob Rich, and to both Rob LeFebvre and Jeff Scott before him, for helping me... | Read more »
Hands-On With Allstar Heroes - A Promisi...
Let’s get this out of the way quickly. Allstar Heroes looks a lot like a certain other recent action RPG release, but it turns out that while it’s not yet available here, Allstar Heroes has been around for much longer than that other title. Now that... | Read more »
Macho Man and Steve Austin Join the Rank...
WWE Immortals, by Warner Bros. Interactive Entertainment and WWE, has gotten a superstar update. You'll now have access to Macho Man Randy Savage and Steve Austin. Both characters have two different versions: Macho Man Randy Savage Renegade or Macho... | Read more »
Fearless Fantasy is Fantastic for the iF...
I actually had my first look at Fearless Fantasy last year at E3, but it was on a PC so there wasn't much for me to talk about. But now that I've been able to play with a pre-release version of the iOS build, there's quite a bit for me to talk... | Read more »
MLB Manager 2015 (Games)
MLB Manager 2015 5.0.14 Device: iOS Universal Category: Games Price: $4.99, Version: 5.0.14 (iTunes) Description: Guide your favorite MLB franchise to glory! MLB Manager 2015, officially licensed by MLB.com and based on the award-... | Read more »
Breath of Light (Games)
Breath of Light 1.0.1421 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.1421 (iTunes) Description: Hold a quiet moment. Breath of Light is a meditative and beautiful puzzle game with a hypnotic soundtrack by... | Read more »
WWE WrestleMania Tags into the App Store
Are You ready to rumble? The official WWE WrestleMania app, by World Wrestling Entertainment, is now available. Now you can get all your WrestleMania info in one place before anyone else. The app offers details on superstar signings, interactive... | Read more »

Price Scanner via MacPrices.net

13-inch 2.5GHz MacBook Pro (refurbished) avai...
The Apple Store has Apple Certified Refurbished 13″ 2.5GHz MacBook Pros available for $829, or $270 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 13″ 2.... Read more
Save up to $80 on iPad Air 2s, NY tax only, f...
 B&H Photo has iPad Air 2s on sale for $80 off MSRP including free shipping plus NY sales tax only: - 16GB iPad Air 2 WiFi: $469.99 $30 off - 64GB iPad Air 2 WiFi: $549.99 $50 off - 128GB iPad... Read more
iMacs on sale for up to $205 off MSRP
B&H Photo has 21″ and 27″ iMacs on sale for up to $205 off MSRP including free shipping plus NY sales tax only: - 21″ 1.4GHz iMac: $1019 $80 off - 21″ 2.7GHz iMac: $1189 $110 off - 21″ 2.9GHz... Read more
Färbe Technik Offers iPhone Battery Charge LI...
Färbe Technik, which manufactures and markets of mobile accessories for Apple, Blackberry and Samsung mobile devices, is offering tips on how to keep your iPhone charged while in the field: •... Read more
Electronic Recyclers International CEO Urges...
Citing a recent story on CNBC about concerns some security professionals have about the forthcoming Apple Watch, John Shegerian, Chairman and CEO of Electronic Recyclers International (ERI), the... Read more
Save up to $380 with Apple refurbished iMacs
The Apple Store has Apple Certified Refurbished iMacs available for up to $380 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 27″ 3.5GHz 5K iMac – $2119 $... Read more
Mac minis on sale for up to $75 off, starting...
MacMall has Mac minis on sale for up to $75 off MSRP including free shipping. Their prices are the lowest available for these models from any reseller: - 1.4GHz Mac mini: $459.99 $40 off - 2.6GHz Mac... Read more
College Student Deals: Additional $50 off Mac...
Take an additional $50 off all MacBooks and iMacs at Best Buy Online with their College Students Deals Savings, valid through April 11, 2015. Anyone with a valid .EDU email address can take advantage... Read more
Mac Pros on sale for up to $260 off MSRP
B&H Photo has Mac Pros on sale for up to $260 off MSRP. Shipping is free, and B&H charges sales tax in NY only: - 3.7GHz 4-core Mac Pro: $2799, $200 off MSRP - 3.5GHz 6-core Mac Pro: $3719.99... Read more
13-inch 2.5GHz MacBook Pro on sale for $100 o...
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

DevOps Software Engineer - *Apple* Pay, iOS...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
*Apple* Retail - Multiple Positions (US) - A...
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
Sr. Technical Services Consultant, *Apple*...
**Job Summary** Apple Professional Services (APS) has an opening for a senior technical position that contributes to Apple 's efforts for strategic and transactional Read more
Lead *Apple* Solutions Consultant - Retail...
**Job Summary** Job Summary The Lead ASC is an Apple employee who serves as the Apple business manager and influencer in a hyper-business critical Reseller's store Read more
*Apple* Pay - Site Reliability Engineer - Ap...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.