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

WhatsApp 0.2.1880 - Desktop client for W...
WhatsApp is the desktop client for WhatsApp Messenger, a cross-platform mobile messaging app which allows you to exchange messages without having to pay for SMS. WhatsApp Messenger is available for... Read more
NeoFinder 6.9.3 - Catalog your external...
NeoFinder (formerly CDFinder) rapidly organizes your data, either on external or internal disks, or any other volumes. It catalogs all your data, so you stay in control of your data archive or disk... Read more
Amadeus Pro 2.3.1 - Multitrack sound rec...
Amadeus Pro lets you use your Mac computer for any audio-related task, such as live audio recording, digitizing tapes and records, converting between a variety of sound formats, etc. Thanks to its... Read more
Yasu 4.0.0 β - System maintenance app; p...
Yasu was created with System Administrators who service large groups of workstations in mind, Yasu (Yet Another System Utility) was made to do a specific group of maintenance tasks quickly within a... Read more
Hazel 4.0.6 - Create rules for organizin...
Hazel is your personal housekeeper, organizing and cleaning folders based on rules you define. Hazel can also manage your trash and uninstall your applications. Organize your files using a familiar... Read more
EtreCheck 3.0.5 - For troubleshooting yo...
EtreCheck is an app that displays the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to... Read more
Skype 7.37.0.178 - Voice-over-internet p...
Skype allows you to talk to friends, family and co-workers across the Internet without the inconvenience of long distance telephone charges. Using peer-to-peer data transmission technology, Skype... Read more
Yasu 4.0.0 β - System maintenance app; p...
Yasu was created with System Administrators who service large groups of workstations in mind, Yasu (Yet Another System Utility) was made to do a specific group of maintenance tasks quickly within a... Read more
Skype 7.37.0.178 - Voice-over-internet p...
Skype allows you to talk to friends, family and co-workers across the Internet without the inconvenience of long distance telephone charges. Using peer-to-peer data transmission technology, Skype... Read more
EtreCheck 3.0.5 - For troubleshooting yo...
EtreCheck is an app that displays the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to... Read more

How to get past Vulture Island's tr...
Vulture Island is a colorful and quirky mish-mash of platforming and puzzles. It’s creative and fresh, but sometimes the game can throw a curveball at you, leaving you stuck as to how you should progress. These tips will help you explore smoothly... | Read more »
The new Clash of Kings is just for Weste...
If you’ve played the original Clash of Kings, you’ll probably recognise the city building, alliance forging and strategic battles in Clash of Kings: The West. What sets this version apart is that it’s tailor made for a Western audience and the... | Read more »
Frost - Survival card game (Games)
Frost - Survival card game 1.12.1 Device: iOS Universal Category: Games Price: $3.99, Version: 1.12.1 (iTunes) Description: *Warning: the game will work on iPhone 5C and above and iPad Pro / 4. Other devices are not supported* | Read more »
How to build and care for your team in D...
Before you hit the trail and become a dog sledding legend, there’s actually a fair bit of prep work to be done. In Dog Sled Saga, you’re not only racing, you’re also building and caring for a team of furry friends. There’s a lot to consider—... | Read more »
How to win every race in Dog Sled Saga
If I had to guess, I’d say Dog Sled Saga is the most adorable racing game on the App Store right now. It’s a dog sled racing sim full of adorable, loyal puppies. Just look at those fluffy little tails wagging. Behind that cute, pixelated facade is... | Read more »
Let the war games commence in Gunship Ba...
Buzz Lightyear famously said, “This isn’t flying, this is falling – with style!” In the case of Gunship Battle: Second War, though, this really is flying - with style! The flight simulator app from Joycity puts you in control of 20 faithfully... | Read more »
How to get a high score in Fired Up
Fired Up is Noodlecake Games’ high score chasing, firefighting adventure. You take control of a wayward firefighter who propels himself up the side of a highrise with blasts of water. Sound silly? It is. It’s also pretty difficult. You can’t... | Read more »
NBA 2K17 (Games)
NBA 2K17 1.0 Device: iOS iPhone Category: Games Price: $7.99, Version: 1.0 (iTunes) Description: Following the record-breaking launch of NBA 2K16, the NBA 2K franchise continues to stake its claim as the most authentic sports video... | Read more »
Dog Sled Saga (Games)
Dog Sled Saga 1.0.1 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0.1 (iTunes) Description: A game by Dan + Lisa As a rookie musher, foster a dogsledding team whose skills will grow if they're treated right. Week by... | Read more »
60 Seconds! Atomic Adventure (Games)
60 Seconds! Atomic Adventure 1.2 Device: iOS Universal Category: Games Price: $2.99, Version: 1.2 (iTunes) Description: 60 Seconds! is a dark comedy atomic adventure of scavenge and survival. Collect supplies and rescue your family... | Read more »

Price Scanner via MacPrices.net

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 $120 off MSRP - 21″ 2.8GHz iMac: $1199.99 $100 off MSRP - 21″ 1... Read more
13-inch 2.7GHz/256GB Retina MacBook Pro on sa...
Amazon.com has the 13″ 2.7GHz/256GB Retina Apple MacBook Pro on sale for $151 off MSRP including free shipping: - 13″ 2.7GHz/256GB Retina MacBook Pro (sku MF840LL/A): $1348 $151 off MSRP Read more
Apple TVs on sale for up to $50 off MSRP
Best Buy has 32GB and 64GB Apple TVs on sale for $40-$50 off MSRP on their online store. Choose free shipping or free local store pickup (if available). Sale prices for online orders only, in-store... Read more
Apple refurbished 13-inch Retina MacBook Pros...
Apple has Certified Refurbished 13″ Retina MacBook Pros available for up to $270 off the cost of new models. An Apple one-year warranty is included with each model, and shipping is free: - 13″ 2.7GHz... Read more
Duplicate Sweeper Free On Mac App Store For O...
To celebrate the launch of Apple’s latest macOS Sierra, Stafford, United Kingdom based Wide Angle Software has announced that its duplicate file finder software, Duplicate Sweeper, is now available... Read more
13-inch Retina MacBook Pros on sale for up to...
B&H Photo has 13″ Retina Apple MacBook Pros on sale for up to $150 off MSRP. Shipping is free, and B&H charges NY tax only: - 13″ 2.7GHz/128GB Retina MacBook Pro: $1174.99 $125 off MSRP - 13... Read more
Evidence Surfaces Pointing To New A10X Chip F...
Citing a job description for a Project Lead position at Apple’s Austin, Texas engineering labs, Motley Fool’s Ashraf Eassa deduces that development is progressing well on Apple’s next-generation in-... Read more
Check Print’R for macOS Allows Anyone to Easi...
Delaware-based Match Software has announced the release and immediate availability of Check Print’R 3.21, an important update to their easy-to-use check printing application for macOS. Check Print’R... Read more
Apple refurbished 11-inch MacBook Airs availa...
Apple has Certified Refurbished 11″ MacBook Airs (the latest models), available for up to $170 off the cost of new models. An Apple one-year warranty is included with each MacBook, and shipping is... Read more
Apple refurbished 15-inch Retina MacBook Pros...
Apple has Certified Refurbished 2015 15″ Retina MacBook Pros available for up to $380 off the cost of new models. An Apple one-year warranty is included with each model, and shipping is free: - 15″ 2... Read more

Jobs Board

Sr. *Apple* Mac Engineer - Net2Source Inc....
…staffing, training and technology. We have following position open with our client. Sr. Apple Mac Engineer6+ Months CTH Start date : 19th Sept Travelling Job If Read more
*Apple* Retail - Multiple Positions-Norfolk,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Restaurant Manager (Neighborhood Captain) - A...
…in every aspect of daily operation. WHY YOU'LL LIKE IT: You'll be the Big Apple . You'll solve problems. You'll get to show your ability to handle the stress and Read more
Lead *Apple* Solutions Consultant - Apple (...
# Lead Apple Solutions Consultant Job Number: 51829230 Detroit, Michigan, United States Posted: Sep. 19, 2016 Weekly Hours: 40.00 **Job Summary** The Lead ASC is an Read more
US- *Apple* Store Leader Program - Apple (Un...
…Summary Learn and grow as you explore the art of leadership at the Apple Store. You'll master our retail business inside and out through training, hands-on Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.