TweetFollow Us on Twitter

Using Controls
Volume Number:1
Issue Number:4
Column Tag:Forth Forum

Using Controls

By Jörg Langowski

In this month’s column I want to introduce to you some concepts of control handling on the Macintosh under MacForth. Controls, as you might have guessed by now, are a very basic concept of the Macintosh user interface: a major part of mouse input to an application is done through controls.

The four main types of controls that show up to you when you work with an application are buttons, check boxes, radio buttons and dials, and these are the ones that we will be talking about this time.

All control handling routines are built into the toolbox ROM. Therefore, one can call them - in principle - from any programming environment as toolbox traps. MacForth, of course, makes this job a little easier by providing a large number of predefined routines. Interestingly enough, most of these routines are already present in Version 1.1, even though the manual says that 1.1 does not support controls. I suppose this was a typo. They wanted to say that it does not document controls. Well, the Inside Macintosh manual does that very extensively and as you will see, it is not hard to transfer those concepts into Forth.

Let’s first look at the definitions of the four control types, as they are given in IM:

Buttons are the little rounded rectangles that have a text inside. When you click a button with the mouse, you tell the application to perform some action as shown in the example below.

“Yes” and “No” are buttons and you may choose either one.

Check boxes show the state of a parameter that can be on or off, and can be clicked on/off with the mouse:

Radio buttons are sets of buttons, only one of which may be on. They are used to set and display parameters that can assume discrete values or states, such as integer numbers:

Dials, the scroll bar being the most familiar example, are used to set and display a parameter that can change continuously (or quasi-continuously, such as the position in a text file).

Generating a control in your active window is very simple, it requires only one toolbox call. Just putting a control into a window like that, however, is useless. You can click and point at it as long as you wish, it won’t do anything unless you tell it what to do. Clicking a control only generates an event that your program has to recognize. For instance, if a radio button is clicked you have to make sure that the corresponding parameter is set on and all others that belong to the same group of radio buttons are turned off. If the page region in a scroll bar is clicked you have to tell the system what to do, change the parameter value and show the scroll bar with its new value.

But then, there is not much more to do. The Control Manager will auto- matically determine if you clicked a control and which one, and will also ‘track’ the control, that is, display it changing while you perform some action on it with the mouse. It will also, if appropriate, inactivate a control, which is then displayed in a different way and any actions on it are ignored (like the scroll bars in the Finder windows if all the icons fit into the window).

Let’s assume we want to generate a window that contains the following controls:

• a scroll bar that can be changed through a range from 0 to 300

• a check box that is used to turn the scroll bar on and off.

An example program that does these functions is given below, and most of it should be self-explanatory. The Toolbox function NewControl that creates a new control in a window, however, has to be explained in a little more detail.

It expects 10 parameters on the stack, from bottom to top:

- 4 bytes for the function result ControlHandle

- WindowPtr, the pointer to the window that the new control belongs to

- boundsRect, the address of a rectangle that gives the control’s size and location in the window’s local coordinates

- title, a pointer to the control’s title

- visible, a boolean value (16 bit); if TRUE, the control is actually drawn inside the window, otherwise, it’s invisible

- value, a 16-bit integer, the control’s initial value

- min, 16-bit integer, the control’s minimum value

- max, 16-bit integer, the control’s maximum value

- procID, 16-bit integer, a number that defines the type of control:

- 0 - simple button, 1 - check box, 2 - radio button, 16 - scroll bar.

- refCon, 32-bit integer, a number that you may use as a unique reference number; it is not used by the Control Manager at all.

This set of parameters is rather impressive, and you can immediately see that none of the standard toolbox trap defining words in MacForth can be used to call this function. First, only function calls with at most one parameter are supported, for the others you have to include space for the result on the stack and use the MT defining word. Second, there are five 16-bit parameters between 32-bit ones, and Forth normally pushes 32-bit items on the stack.

MacForth 2.0 has the word ADD.CONTROL built in, which is called with the stack set up like above, only the integers are all 32-bit. ADD.CONTROL then converts visible, value, min, max, and procID to 16 bits and calls NewControl, which creates the control. However, if you have MacForth 1.1, you can define your own ADD.CONTROL by using the 16-bit push PUSHW that was defined in the last MacTech. The example below contains the definitions of PUSHW and ADD.CONTROL.

The scroll bar that we define is horizontal. The up button and page-up regions of a horizontal bar are on the left side, but the bar is incremented to the right (an inconsistency in the Control Manager). Therefore the program decrements the control’s value when the up button is clicked and increments it on the down button.

The only other control in the example is a check box that turns the scroll bar on and off. I have not included simple buttons or radio buttons; you may want to try them out on your own by setting procID to different values. Remember, if you define a set of radio buttons, your program has to keep track of which one is on and turn the others off. There is no way how the Control Manager could know which buttons belong to the same group.

( Demo program for using the Control Manager from Mac Forth )
( © 1985  MacTutor by J. Langowski  )

( pushw, new.control ) hex
: pushw s0 @ >R sp@ 2- s0 ! sp! r> s0 ! drop ;
A954 mt (new.control)
: add.control
  >r ( refCon )   >r ( procID )  >r ( max )   >r ( min )   >r ( value 
  pushw  ( visible ) r> pushw  ( value )
  r> pushw  ( min )  r> pushw ( max ) r> pushw  ( procID )  r> ( refCon 
 (new.control)  ;

( test window for new.control )              ( JL Jan 1985 )
decimal  new.window my.window  50 100 200 450 my.window w.bounds + my.window w.attributes   my.window add.window
50 50 75 300 rect my.scroll
( set up scroll bar )
0 my.window my.scroll 
“  “ ( no title )
 -1  ( visible=true )
100  ( value )
0    ( min )
300  ( max )
16   ( procID for scroll bar )
here ( to get a unique ref # )
constant my.control in.heap ( so that handle is released when FORGETting 

( on/off box for test window )
25 50 40 200 rect button.a.rect ( check box )
0 my.window button.a.rect “  Scroll Bar Off” -1 0 0 1 1 ( check box ) 

here add.control
constant my.button in.heap   my.window show.controls
80 50 95 150 rect text.rect  ( for output )

( control tracking )
( track control, given a control handle and mouse position, tracks a 
control )
: my.track this.control @ @mouse track.control ;

( get.control, given a control handle, gets the value of that control 
: show.value my.control get.control text.rect erase.rect
             0 textfont  50 90 .” Value:” . .”    “  ;

( set.control, given a control handle and an integer, sets the control 
  that integer value )

( scroll bar )
: do.thumb  my.track drop get.window show.controls show.value ;
: inc.scroll this.control @ dup get.control 1+ set.control show.value 
: dec.scroll this.control @ dup get.control 1- set.control show.value 
: inc10.scroll this.control @ dup get.control 10 + set.control show.value 
: dec10.scroll this.control @ dup get.control 10 - set.control show.value 

( scroll bar )
:  case in.thumb of  do.thumb   endof
           up.button of dec.scroll endof  down.button of inc.scroll endof
           page.up of dec10.scroll endof  page.down of inc10.scroll endof
                 endcase  ;

( check box )
( hilite.control, given control handle and integer value, sets the control
 active if value=0 and inactive if value=255 ) 
: do.button drop my.track if this.control @ dup get.control 1 swap -
                         my.control over 255 * hilite.control set.control 
     get.window show.controls ;

( control actions )
: do.controls swap  case my.control of endof
                         my.button  of  do.button endof
                    endcase ;

( event loop for test window )
: my.action show.value if begin
                          case mouse.down of  @mouse.dn get.window
                             find.control ?dup if do.controls then endof
                          endcase again
  else .” My Window Deactivated” then ;

my.window on.activate my.action


Community Search:
MacTech Search:

Software Updates via MacUpdate

Microsoft Office 2016 16.11 - Popular pr...
Microsoft Office 2016 - Unmistakably Office, designed for Mac. The new versions of Word, Excel, PowerPoint, Outlook, and OneNote provide the best of both worlds for Mac users - the familiar Office... Read more
Adobe Photoshop CC 2018 19.1.2 - Profess...
Photoshop CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Photoshop customer). Adobe Photoshop CC 2018, the industry standard... Read more
Adobe Dreamweaver CC 2018 -...
Dreamweaver CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Dreamweaver customer). Adobe Dreamweaver CC 2018 allows you to... Read more
Adobe Flash Player - Plug-in...
Adobe Flash Player is a cross-platform, browser-based application runtime that provides uncompromised viewing of expressive applications, content, and videos across browsers and operating systems.... Read more
Drive Genius 5.2.0 - $79.00
Drive Genius features a comprehensive Malware Scan. Automate your malware protection. Protect your investment from any threat. The Malware Scan is part of the automated DrivePulse utility. DrivePulse... Read more
MegaSeg 6.0.6 - Professional DJ and radi...
MegaSeg is a complete solution for pro audio/video DJ mixing, radio automation, and music scheduling with rock-solid performance and an easy-to-use design. Mix with visual waveforms and Magic... Read more
ffWorks 1.0.7 - Convert multimedia files...
ffWorks (was iFFmpeg), focused on simplicity, brings a fresh approach to the use of FFmpeg, allowing you to create ultra-high-quality movies without the need to write a single line of code on the... Read more
Dash 4.1.5 - Instant search and offline...
Dash is an API documentation browser and code snippet manager. Dash helps you store snippets of code, as well as instantly search and browse documentation for almost any API you might use (for a full... Read more
Evernote 7.0.3 - Create searchable notes...
Evernote allows you to easily capture information in any environment using whatever device or platform you find most convenient, and makes this information accessible and searchable at anytime, from... Read more
jAlbum Pro 15.3 - Organize your digital...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. You can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly... Read more

Latest Forum Discussions

See All

Around the Empire: What have you missed...
Oh hi nice reader, and thanks for popping in to check out our weekly round-up of all the stuff that you might have missed across the Steel Media network. Yeah, that's right, it's a big ol' network. Obviously 148Apps is the best, but there are some... | Read more »
All the best games on sale for iPhone an...
It might not have been the greatest week for new releases on the App Store, but don't let that get you down, because there are some truly incredible games on sale for iPhone and iPad right now. Seriously, you could buy anything on this list and I... | Read more »
Everything You Need to Know About The Fo...
In just over a week, Epic Games has made a flurry of announcements. First, they revealed that Fortnite—their ultra-popular PUBG competitor—is coming to mobile. This was followed by brief sign-up period for interested beta testers before sending out... | Read more »
The best games that came out for iPhone...
It's not been the best week for games on the App Store. There are a few decent ones here and there, but nothing that's really going to make you throw down what you're doing and run to the nearest WiFi hotspot in order to download it. That's not to... | Read more »
Death Coming (Games)
Death Coming Device: iOS Universal Category: Games Price: $1.99, Version: (iTunes) Description: --- Background Story ---You Died. Pure and simple, but death was not the end. You have become an agent of Death: a... | Read more »
Hints, tips, and tricks for Empires and...
Empires and Puzzles is a slick match-stuff RPG that mixes in a bunch of city-building aspects to keep things fresh. And it's currently the Game of the Day over on the App Store. So, if you're picking it up for the first time today, we thought it'd... | Read more »
What You Need to Know About Sam Barlow’s...
Sam Barlow’s follow up to Her Story is #WarGames, an interactive video series that reimagines the 1983 film WarGames in a more present day context. It’s not exactly a game, but it’s definitely still interesting. Here are the top things you should... | Read more »
Pixel Plex Guide - How to Build Better T...
Pixel Plex is the latest city builder that has come to the App Store, and it takes a pretty different tact than the ones that came before it. Instead of being in charge of your own city by yourself, you have to work together with other players to... | Read more »
Fortnite Will Be Better Than PUBG on Mob...
Before last week, if you asked me which game I prefer between Fortnite Battle Royale and PlayerUnknown’s Battlegrounds (PUBG), I’d choose the latter just about 100% of the time. Now that we know that both games are primed to hit our mobile screens... | Read more »
Siege of Dragonspear (Games)
Siege of Dragonspear 2.5.12 Device: iOS Universal Category: Games Price: $9.99, Version: 2.5.12 (iTunes) Description: Experience the Siege of Dragonspear, an epic Baldur’s Gate tale, filled with with intrigue, magic, and monsters.... | Read more »

Price Scanner via

Sunday Sales: $200 off 13″ Touch Bar MacBook...
Amazon has new 2017 13″ 3.1GHz Touch Bar MacBook Pros on sale this weekend for $200 off MSRP, each including free shipping: – 13″ 3.1GHz/256GB Space Gray MacBook Pro (MPXV2LL/A): $1599.99 $200 off... Read more
B&H drops prices on 15″ MacBook Pros up t...
B&H Photo has dropped prices on new 2017 15″ MacBook Pros, now up to $300 off MSRP and matching Adorama’s price drop yesterday. Shipping is free, and B&H charges sales tax for NY & NJ... Read more
Apple restocks Certified Refurbished 2017 13″...
Apple has restocked Certified Refurbished 2017 13″ 2.3GHz MacBook Pros for $200-$230 off MSRP. A standard Apple one-year warranty is included with each MacBook, models receive new outer cases, and... Read more
13″ Space Gray Touch Bar MacBook Pros on sale...
Adorama has new 2017 13″ Space Gray Touch Bar MacBook Pros on sale for $150 off MSRP. Shipping is free, and Adorama charges sales tax in NY & NJ only: – 13″ 3.1GHz/256GB Space Gray MacBook Pro (... Read more
Best deal of the year on 15″ Apple MacBook Pr...
Adorama has New 2017 15″ MacBook Pros on sale for up to $300 off MSRP. Shipping is free, and Adorama charges sales tax in NJ and NY only: – 15″ 2.8GHz Touch Bar MacBook Pro Space Gray (MPTR2LL/A): $... Read more
Save $100-$150+ on 13″ Touch Bar MacBook Pros...
B&H Photo has 13″ Touch Bar MacBook Pros on sale for $100-$150 off MSRP. Shipping is free, and B&H charges sales tax for NY & NJ residents only: – 13″ 3.1GHz/256GB Space Gray MacBook Pro... Read more
Current deals on 27″ Apple iMacs, models up t...
B&H Photo has 27″ iMacs on sale for up to $150 off MSRP. Shipping is free, and B&H charges sales tax for NY & NJ residents only: – 27″ 3.8GHz iMac (MNED2LL/A): $2149 $150 off MSRP – 27″ 3... Read more
Thursday Deal: 13″ 2.3GHz MacBook Pro for $11...
B&H Photo has the 13″ 2.3GHz/128GB Space Gray MacBook Pro on sale for $100 off MSRP. Shipping is free, and B&H charges sales tax for NY & NJ residents only: – 13-inch 2.3GHz/128GB Space... Read more
How to save $100-$190 on 10″ & 12″ iPad P...
Apple is now offering Certified Refurbished 2017 10″ and 12″ iPad Pros for $100-$190 off MSRP, depending on the model. An Apple one-year warranty is included with each model, and shipping is free: –... Read more
Silver 12″ 1.3GHz MacBook on sale at B&H...
B&H Photo has the 2017 12″ 1.3GHz Silver MacBook on sale for $1399.99 including free shipping plus sales tax for NY & NJ residents only. Their price is $200 off MSRP, and it’s the lowest... Read more

Jobs Board

Art Director, *Apple* Music + Beats1 Market...
# Art Director, Apple Music + Beats1 Marketing Design Job Number: 113258081 Culver City, California, United States Posted: 07-Mar-2018 Weekly Hours: 40.00 **Job Read more
*Apple* Solution Consultant - Apple (United...
# Apple Solution Consultant Job Number: 113569564 Williston, Vermont, United States Posted: 06-Mar-2018 Weekly Hours: 40.00 **Job Summary** Are you passionate about Read more
*Apple* Media Products (AMP) Engineering Man...
# Apple Media Products (AMP) Engineering Manager Job Number: 86497853 Santa Clara Valley, California, United States Posted: 07-Mar-2018 Weekly Hours: 40.00 **Job Read more
QA Automation Engineer, *Apple* Pay - Apple...
# QA Automation Engineer, Apple Pay Job Number: 113202642 Santa Clara Valley, California, United States Posted: 02-Mar-2018 Weekly Hours: 40.00 **Job Summary** At Read more
Lead *Apple* Solution Consultant - Apple (U...
# Lead Apple Solution Consultant Long Island NY Job Number: 113486035 Long Island City, New York, United States Posted: 07-Mar-2018 Weekly Hours: 40.00 **Job Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.