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

Microsoft Remote Desktop 8.0.16 - Connec...
With Microsoft Remote Desktop, you can connect to a remote PC and your work resources from almost anywhere. Experience the power of Windows with RemoteFX in a Remote Desktop client designed to help... Read more
Spotify 1.0.4.90. - Stream music, create...
Spotify is a streaming music service that gives you on-demand access to millions of songs. Whether you like driving rock, silky R&B, or grandiose classical music, Spotify's massive catalogue puts... Read more
djay Pro 1.1 - Transform your Mac into a...
djay Pro provides a complete toolkit for performing DJs. Its unique modern interface is built around a sophisticated integration with iTunes and Spotify, giving you instant access to millions of... Read more
Vivaldi 1.0.118.19 - Lightweight browser...
Vivaldi browser. In 1994, two programmers started working on a web browser. Our idea was to make a really fast browser, capable of running on limited hardware, keeping in mind that users are... Read more
Stacks 2.6.11 - New way to create pages...
Stacks is a new way to create pages in RapidWeaver. It's a plugin designed to combine drag-and-drop simplicity with the power of fluid layout. Features: Fluid Layout: Stacks lets you build pages... Read more
xScope 4.1.3 - Onscreen graphic measurem...
xScope is powerful set of tools that are ideal for measuring, inspecting, and testing on-screen graphics and layouts. Its tools float above your desktop windows and can be accessed via a toolbar,... Read more
Cyberduck 4.7 - FTP and SFTP browser. (F...
Cyberduck is a robust FTP/FTP-TLS/SFTP browser for the Mac whose lack of visual clutter and cleverly intuitive features make it easy to use. Support for external editors and system technologies such... Read more
Labels & Addresses 1.7 - Powerful la...
Labels & Addresses is a home and office tool for printing all sorts of labels, envelopes, inventory labels, and price tags. Merge-printing capability makes the program a great tool for holiday... Read more
teleport 1.2.1 - Use one mouse/keyboard...
teleport is a simple utility to let you use one single mouse and keyboard to control several of your Macs. Simply reach the edge of your screen, and your mouse teleports to your other Mac! The... Read more
Apple iMovie 10.0.8 - Edit personal vide...
With an all-new design, Apple iMovie lets you enjoy your videos like never before. Browse your clips more easily, instantly share your favorite moments, and create beautiful HD movies and Hollywood-... Read more

Use Batting Average and the Apple Watch...
Batting Average, by Pixolini, is designed to help you manage your statistics. Every time you go to bat, you can use your Apple Watch to track  your swings, strikes, and hits. [Read more] | Read more »
Celebrate Studio Pango's 3rd Annive...
It is time to party, Pangoland pals! Studio Pango is celebrating their 3rd birthday and their gift to you is a new update to Pangoland. [Read more] | Read more »
Become the World's Most Important D...
Must Deliver, by cherrypick games, is a top-down endless-runner witha healthy dose of the living dead. [Read more] | Read more »
SoundHound + LiveLyrics is Making its De...
SoundHound Inc. has announced that SoundHound + LiveLyrics, will be one of the first third-party apps to hit the Apple Watch. With  SoundHound you'll be able to tap on your watch and have the app recognize the music you are listening to, then have... | Read more »
Adobe Joins the Apple Watch Lineup With...
A whole tidal wave of apps are headed for the Apple Watch, and Adobe has joined in with 3 new ways to enhance your creativity and collaborate with others. The watch apps pair with iPad/iPhone apps to give you total control over your Adobe projects... | Read more »
Z Steel Soldiers, Sequel to Kavcom'...
Kavcom has released Z Steel Soldiers, which continues the story of the comedic RTS originally created by the Bitmap Brothers. [Read more] | Read more »
Seene Lets You Create 3D Images With You...
Seene, by Obvious Engineering, is a 3D capture app that's meant to allow you to create visually stunning 3D images with a tap of your finger, and then share them as a 3D photo, video or gif. [Read more] | Read more »
Lost Within - Tips, Tricks, and Strategi...
Have you just downloaded Lost Within and are you in need of a guiding hand? While it’s not the toughest of games out there you might still want some helpful tips to get you started. [Read more] | Read more »
Entertain Your Pet With Your Watch With...
The Petcube Camera is a device that lets you use live video to check in on your pet, talk to them, and play with them using a laser pointer - all while you're away. And the Petcube app is coming to the Apple Watch, so you'll be able to hang out with... | Read more »
Now You Can Manage Your Line2 Calls With...
You'll be able to get your Line2 cloud phone service on the Apple Watch very soon. The watch app can send and receive messages using hands-free voice dictation, or by selecting from a list of provided responses. [Read more] | Read more »

Price Scanner via MacPrices.net

Intel Compute Stick: A New Mini-Computing For...
The Intel Compute Stick, a new pocket-sized computer based on a quad-core Intel Atom processor running Windows 8.1 with Bing, is available now through Intel Authorized Dealers across much of the... Read more
Heal to Launch First One-Touch House Call Doc...
Santa Monica, California based Heal, a pioneer in on-demand personal health care services — will offer the first one-touch, on-demand house call doctor app for the Apple Watch. Heal’s Watch app,... Read more
Mac Notebooks: Avoiding MagSafe Power Adapter...
Apple Support says proper usage, care, and maintenance of Your Mac notebook’s MagSafe power adapter can substantially increase the the adapter’s service life. Of course, MagSafe itself is an Apple... Read more
12″ Retina MacBook In Shootout With Air And P...
BareFeats’ rob-ART morgan has posted another comparison of the 12″ MacBook with other Mac laptops, noting that the general goodness of all Mac laptops can make which one to purchase a tough decision... Read more
FileMaker Go for iPad and iPhone: Over 1.5 Mi...
FileMaker has announced that its FileMaker Go for iPad and iPhone app has surpassed 1.5 million downloads from the iTunes App Store. The milestone confirms the continued popularity of the FileMaker... Read more
Sale! 13-inch 2.7GHz Retina MacBook Pro for $...
 Best Buy has the new 2015 13″ 2.7GHz/128GB Retina MacBook Pro on sale for $1099 – $200 off MSRP. Choose free shipping or free local store pickup (if available). Price for online orders only, in-... Read more
Minimalist MacBook Confirms Death of Steve Jo...
ReadWrite’s Adriana Lee has posted a eulogy for the “Digital Hub” concept Steve Jobs first proposed back in 2001, declaring the new 12-inch MacBook with its single, over-subscribed USB-C port to be... Read more
13-inch 2.7GHz Retina MacBook Pro for $1234 w...
Adorama has the 13″ 2.7GHz/128GB Retina MacBook Pro in stock for $1234.99 ($65 off MSRP) including free shipping plus a free LG external DVD/CD optical drive. Adorama charges sales tax in NY & NJ... Read more
13-inch 2.5GHz MacBook Pro available for $999...
 Adorama has the 13-inch 2.5GHz MacBook Pro on sale for $999 including free shipping plus NY & NJ sales tax only. Their price is $100 off MSRP. Read more
Save up to $600 with Apple refurbished Mac Pr...
The Apple Store is offering Apple Certified Refurbished Mac Pros for up to $600 off the cost of new models. An Apple one-year warranty is included with each Mac Pro, and shipping is free. The... Read more

Jobs Board

*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
*Apple* Support Technician IV - Jack Henry a...
Job Description Jack Henry & Associates is seeking an Apple Support Technician. This position while acting independently, ensures the proper day-to-day control of Read more
*Apple* Client Systems Solution Specialist -...
…drive revenue and profit in assigned sales segment and/or region specific to the Apple brand and product sets. This person will work directly with CDW Account Managers Read more
*Apple* Software Support - Casper (Can work...
…experience . Full knowledge of Mac OS X and prior . Mac OSX / Server . Apple Remote Desktop . Process Documentation . Ability to prioritize multiple tasks in a fast pace Read more
*Apple* Software Support - Xerox Corporation...
…Imaging experience Full knowledge of Mac OS X and prior Mac OSX / Server Apple Remote Desktop Process Documentation Ability to prioritize multiple tasks in a fast pace Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.