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

Luminar 1.0.2 - Powerful, adaptive, conf...
Luminar is the new full-featured image editor that adapts to the way you edit photos. Over 300 essential tools to fix, edit, and enhance your photos with comfort. The future of photo editing is here... Read more
Slack 2.3.3 - Collaborative communicatio...
Slack is a collaborative communication app that simplifies real-time messaging, archiving, and search for modern working teams. Version 2.3.3: Fixed window zoom jumping back-and-forth OS X 10.9... Read more
WhatRoute 2.0.10 - Geographically trace...
WhatRoute is designed to find the names of all the routers an IP packet passes through on its way from your Mac to a destination host. It also measures the round-trip time from your Mac to the router... Read more
Luminar 1.0.2 - Powerful, adaptive, conf...
Luminar is the new full-featured image editor that adapts to the way you edit photos. Over 300 essential tools to fix, edit, and enhance your photos with comfort. The future of photo editing is here... Read more
WhatRoute 2.0.10 - Geographically trace...
WhatRoute is designed to find the names of all the routers an IP packet passes through on its way from your Mac to a destination host. It also measures the round-trip time from your Mac to the router... Read more
Slack 2.3.3 - Collaborative communicatio...
Slack is a collaborative communication app that simplifies real-time messaging, archiving, and search for modern working teams. Version 2.3.3: Fixed window zoom jumping back-and-forth OS X 10.9... Read more
Lens Blur 1.4.3 - True out-of-focus boke...
Lens Blur transforms your existing photo into true SLR-quality out-of-focus bokeh effect! Everyone needs a gorgeous personalized background for a social profile, blog, Web/UI design, presentation, or... Read more
CleanMyMac 3.6.0 - $39.95
CleanMyMac makes space for the things you love. Sporting a range of ingenious new features, CleanMyMac lets you safely and intelligently scan and clean your entire system, delete large, unused files... Read more
DEVONthink Pro 2.9.8 - Knowledge base, i...
DEVONthink Pro is your essential assistant for today's world, where almost everything is digital. From shopping receipts to important research papers, your life often fills your hard drive in the... Read more
MacFamilyTree 8.1 - Create and explore y...
MacFamilyTree gives genealogy a facelift: modern, interactive, convenient and fast. Explore your family tree and your family history in a way generations of chroniclers before you would have loved.... Read more

Latest Forum Discussions

See All

Amateur Surgeon 4 Guide: Become the worl...
It's time to wield your trusty pizza cutter again, as Amateur Surgeon has returned with a whole fresh set of challenges (and some old, familiar ones, too). Starting anew isn't easy, especially when all you have at your disposal is a lighter, the... | Read more »
Le Parker: Sous Chef Extraordinaire (Ga...
Le Parker: Sous Chef Extraordinaire 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: | Read more »
Telltale Games really is working on a Gu...
Telltale Games' next episodic adventure is indeed Guardians of the Galaxy. A document tied to the voice actors strike suggested that the project was in the work, but now we have direct confirmation following an announcement at the Game Awards that... | Read more »
Amateur Surgeon returns to iOS and Andro...
Amateur Surgeon and its two sequels disappeared from the App Store some time and it was sad days for all. But now, just in time for the holidays, the Adult Swim favorite makes its joyous return in the shape of Amateur Surgeon 4, a remake with... | Read more »
The best board games on mobile
Sometimes you need to ditch all of the high speed, high action games in favor of something a little more traditional. If you don't feel like parting ways from your mobile device, though, there are still plenty of ways to get that old-school fix.... | Read more »
The best Facebook Messenger Instant Game...
Facebook's new Instant Games is now here, meaning you can play games with your friends directly via Facebook. It's a fun new way to connect with friends, of course, but it's also proving to be a solid gaming experience in its own right, with a... | Read more »
You can now play game's on Facebook...
Facebook launched its new Instant Games platform in an exciting new attempt to engage its user base. As a result, you can now play a number of different games directly through Facebook Messenger. All of these games run with HTML5, meaning you play... | Read more »
Apollo Justice Ace Attorney (Games)
Apollo Justice Ace Attorney 1.00.00 Device: iOS Universal Category: Games Price: $.99, Version: 1.00.00 (iTunes) Description: Court Is Back In Session Star as rookie defense attorney, Apollo Justice, as he visits crime scenes,... | Read more »
KORG iWAVESTATION (Music)
KORG iWAVESTATION 1.0 Device: iOS Universal Category: Music Price: $19.99, Version: 1.0 (iTunes) Description: A revolutionary new world of sound.The Wave Sequence Synthesizer for iPad - KORG iWAVESTATION | Read more »
Don't Grind Guide: Tips for becomin...
Don’t Grind is a surprising, derpy little one touch game with fun hand-drawn graphics. The goal is simple -- get the high score without being chopped to bits. That can be tough when you’re not used to the game, and that’s compounded by the fact... | Read more »

Price Scanner via MacPrices.net

Parallels Toolbox 1.3 for Mac Offers 25 Singl...
Parallels has launched Parallels Toolbox 1.3 for Mac, an upgrade that adds five new utilities to the stand-alone application which was released in August and is available exclusively online at http... Read more
OWC Mercury Elite Pro Dual mini Ultra-Portabl...
OWC has introduced the new OWC Mercury Elite Pro Dual mini, a powerful yet ultra-portable dual-drive RAID solution. The new Mercury Elite Pro Dual mini packs phenomenal performance into a small... Read more
Clearance 13-inch Retina MacBook Pros availab...
B&H Photo has clearance 2015 13″ Retina Apple MacBook Pros available for up to $200 off original MSRP. Shipping is free, and B&H charges NY tax only: - 13″ 2.7GHz/128GB Retina MacBook Pro: $... Read more
Roundup of 2016 13-inch 2.0GHz MacBook Pro sa...
B&H has the non-Touch Bar 13″ MacBook Pros in stock today for $50-$100 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.0GHz MacBook Pro Space Gray (MLL42LL/A): $1449 $... Read more
New 13-inch 2.0GHz Space Gray MacBook Pro in...
Adorama has the new 13″ 2.0GHz Space Gray MacBook Pro (non-Touch Bar, MLL42LL/A) in stock for $1499 including a free 3-year AppleCare Protection Plan. Shipping is free, and Adorama charges sales tax... Read more
Finnair Adopts iOS Enterprise iPad Apps from...
Finnair and IBM have announced a first-of-its-kind agreement to utilize iOS enterprise apps from IBM to support the airline’s overall digital transformation. Finnair is focused on Asia-Europe traffic... Read more
Tech21 Launches Evo Go iPhone 7 Case Availabl...
Tech21 has announced the launch of the Evo Go case for Apple iPhone 7 and iPhone 7 Plus, exclusively at T-Mobile. Available online and at participating T-Mobile stores nationwide, Evo Go cases start... Read more
Apple Turns (RED) with More Ways to Join the...
In recognition of World AIDS Day, Apple is offering more ways than ever for customers to join (RED) in its mission to create an AIDS-free generation. Apple is the worlds largest corporate contributor... Read more
Deals on new 15-inch Touch Bar MacBook Pros,...
B&H Photo has new 2016 Apple 15″ Touch Bar MacBook Pro models in stock today with some available for $50 off MSRP, each including free shipping plus NY sales tax only: - 15″ 2.7GHz Touch Bar... Read more
12-inch Retina MacBooks on sale for up to $10...
12-inch Retina MacBooks remain on sale at B&H Photo with models available for up to $100 off MSRP. Shipping is free, and B&H charges NY sales tax only. B&H will also include a free copy... Read more

Jobs Board

*Apple* Retail - Multiple Positions- White P...
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
Automotive Detailer - *Apple* Used Autos -...
We are currently conductinginterviews and will be accepting applications for a part-time detailer. Apple Used Autos is a great place to work andstart a career. We Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, 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
*Apple* & PC Desktop Support Technician...
Apple & PC Desktop Support Technician job in Dallas TX Introduction: We have immediate job openings for several Desktop Support Technicians with one of our most Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.