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
close.box size.box + 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 # )
add.control 
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 move.to .” Value:” . .”    “  ;

( set.control, given a control handle and an integer, sets the control 
to 
  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 )
: do.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 
then
     get.window show.controls ;

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

( event loop for test window )
: my.action show.value if begin do.events
                          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

Trend Micro 11.0.2062 - An essential sec...
Trend Micro Antivirus provides essential security for macOS with real-time malware detection and mitigation in an affordable solution with a simple, intuitive interface. However, be aware that more... Read more
Backblaze 7.0.2.490 - Online backup serv...
Backblaze is an online backup service designed from the ground-up for the Mac. With unlimited storage available for $6 per month, as well as a free 15-day trial, peace of mind is within reach with... Read more
Pro Video Formats 2.2.1 - Updates for pr...
Pro Video Formats includes support for the following professional video codecs: Apple Intermediate Codec Apple ProRes AVC-Intra 50 / 100 / 200 / 4:4:4 / LT AVC-LongG XAVC XF-AVC DVCPRO HD HDV XDCAM... Read more
Boom 3D 1.3.11 - $19.99
Boom 3D is a revolutionary app with 3D Surround Sound and phenomenally rich and intense audio that is realistic and works on any headphones. Features 3D surround sound Built-in audio player... Read more
Final Cut Pro 10.5.2 - Professional vide...
Redesigned from the ground up, Final Cut Pro combines revolutionary video editing with a powerful media organization and incredible performance to let you create at the speed of thought.... Read more
Chromium 89.0.4389.72 - Fast and stable...
Chromium is an open-source browser project that aims to build a safer, faster, and more stable way for all Internet users to experience the web. Version 89.0.4389.72: Complete list of changes can... Read more
iMovie 10.2.3 - Edit personal videos and...
With a streamlined design and intuitive editing features, iMovie lets you create Hollywood-style trailers and beautiful movies like never before. Browse your video library, share favorite moments,... Read more
OmniPlan 4.2.5 - Professional-grade proj...
With OmniPlan, you can create logical, manageable project plans with Gantt charts, schedules, summaries, milestones, and critical paths. Break down the tasks needed to make your project a success,... Read more
Compressor 4.5.2 - Adds power and flexib...
Compressor adds power and flexibility to Final Cut Pro X export. Customize output settings, work faster with distributed encoding, and tap into a comprehensive set of delivery features. Features:... Read more
Motion 5.5.1 - Create and customize Fina...
Motion is designed for video editors, Motion 5 lets you customize Final Cut Pro titles, transitions, and effects. Or create your own dazzling animations in 2D or 3D space, with real-time feedback as... Read more

Latest Forum Discussions

See All

Frogger in Toy Town's latest update...
Konami Digital Entertainment has announced today that their Apple Arcade title Frogger in Toy Town has been updated to introduce a new ranked Endurance Mode. This new game variant's arrival is also accompanied by a few other changes. [Read more] | Read more »
Mitoza is surreal adventure toy you can...
The folks behind the Rusty Lake games have just put a new title onto the App Store. Second Maze, Rusty Lake's collaborative publishing brand, has just brought this 10 year old adventure game from Gal Mamalya to mobile. The best part about all of... | Read more »
Pocket Gamer Awards 2021: You have five...
Three weeks ago our sister site, Pocket Gamer, entered the voting stage for the upcoming Pocket Gamer Awards 2021 and is now in the final stretch. You only have a few hours left to vote for the games you’ve enjoyed on mobile in the past year, as... | Read more »
Patty Stack is a casual arcade game, ava...
Patty Stack is a casual arcade title that's available now for iOS and Android. It's the debut game from developer Feeka Games tasks players with making an increasingly giant burger tower. Think of it as Tower Bloxx but more edible. [Read more] | Read more »
Distract Yourself With These Great Mobil...
There’s a lot going on right now, and I don’t really feel like trying to write some kind of pithy intro for it. All I’ll say is lots of people have been coming together and helping each other in small ways, and I’m choosing to focus on that as I... | Read more »
Genshin Impact Guide - Gacha Strategy: W...
This is part 2 of our Genshin Impact gacha strategy guides. See part 1 here. You can check out more guides for Genshin Impact here. | Read more »
Slashy Camp is a new endless runner insp...
Blue Wizard Digital has released Slashy Camp onto iOS and Android after it spent a short amount of time in early access. [Read more] | Read more »
Kinder World is a relaxing game about lo...
Lumi Interactive is releasing a game called Kinder World later this year on iOS and Android, which is all about looking after houseplants. [Read more] | Read more »
Steam Link Spotlight - Fights in Tight S...
Steam Link Spotlight is a feature where we look at PC games that play exceptionally well using the Steam Link app. Our last entry was on Hades. Read about how it plays using Steam Link over here. | Read more »
Lyxo, the light-based puzzler for mobile...
Vienna-based independent game studio Emoak has just released its unique light-based puzzler for iOS and Android. Founded in 2014 by Tobias Sturn, the company is also the creative force behind the infinite climbing game Paper Climb, as well as the... | Read more »

Price Scanner via MacPrices.net

Weekend Sale: $100 off Apple iPad Magic Keybo...
Amazon has Apple iPad Magic Keyboards on sale for $100 off MSRP for a limited time. Amazon’s prices are the lowest available for iPad Magic Keyboard from any Apple reseller this weekend: – Magic... Read more
Gazelle now offering a full line of refurbish...
Gazelle is now offering a full range of discounted, refurbished, unlocked Apple iPhone 12 models starting at $649. iPhones are offered in Fair, Good, and Excellent conditions, and multiple colors are... Read more
These are the latest discounted iPhones Apple...
Apple has a range of Certified Refurbished iPhones available right now starting at only $339. Apple includes a standard one-year warranty, new outer shell, and shipping is free. According to Apple, “... Read more
Save up to $64 on new M1 MacBook Airs at Expe...
Apple reseller Expercom has 2020 13″ M1 MacBook Airs on sale for $51-$64 off Apple’s MSRP with prices starting at $947.96. In addition to their MacBook Air sale prices, take $50 off AppleCare+ when... Read more
Discounts available on 16″ MacBook Pros with...
Upgrade a 16″ 6-Core or 8-Core MacBook Pro from 16GB of standard RAM to 32GB at Adorama, and save $100-$210 over Apple’s price for this custom option: – 16″ 6-Core MacBook Pro/32GB RAM: $2699, save $... Read more
10.9″ iPad Airs on sale for $50-$70 off Apple...
Amazon has new 2020 10.9″ Apple WiFi iPad Airs in stock and on sale today for up to $70 off MSRP with prices starting at $549. Note that Amazon’s sale price might be restricted to certain colors (see... Read more
Apple restocks 2020 27″ 5K iMacs for up to $3...
After an initial offering in January, Apple has restocked a full line of Certified Refurbished 2020 27″ 5K iMacs starting at $1529 and up to $350 off original MSRP. Apple’s one-year warranty is... Read more
Sale! 16″ 8-Core MacBook Pro for $2449, $350...
Apple reseller Adorama has the 16″ 2.3GHz 8-Core Space Gray MacBook Pro in stock and on sale today for $2449 including free shipping. Their price is $350 off Apple’s MSRP for this model, and it’s the... Read more
Roundup of 13″ Multi-Core Intel MacBook Pro s...
Apple resellers are offering significant sales & deals this week on 2020 13″ MacBook Pros with 10th generation Intel CPUs. Take up to $250 off Apple’s MSRP, get free fast shipping, and/or pay no... Read more
64GB iPhone 8 Plus available for $379 at Appl...
Apple has the 64GB iPhone 8 Plus in Space Gray & Gold colors available for $379 today, Certified Refurbished. Each phone is unlocked and comes with Apple’s standard 1-year warranty and free... Read more

Jobs Board

Geek Squad Advanced Repair *Apple* Professi...
**795178BR** **Job Title:** Geek Squad Advanced Repair Apple Professional **Job Category:** Store Associates **Store Number or Department:** 001406-Allen Park-Store Read more
Geek Squad *Apple* Consultation Professiona...
**796549BR** **Job Title:** Geek Squad Apple Consultation Professional **Job Category:** Store Associates **Store Number or Department:** 001800-Hot Springs-Store Read more
*Apple* Mobility Specialist - Best Buy (Unit...
**796014BR** **Job Title:** Apple Mobility Specialist **Job Category:** Store Associates **Store Number or Department:** 001776-Woodmore Towne Centre-Store **Job Read more
Systems Architect, *Apple* Production Engin...
…package beginning on your first day? If so, we hope you'll keep reading! The Apple Sales Engineering and account team is looking for a stellar presales engineer with Read more
Systems Engineer, Webscale, *Apple* Retail,...
…beginning on your first day? If so, we hope you'll keep reading! The Apple Sales Engineering team is looking for a pre-sales engineer with Enterprise engineering Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.