TweetFollow Us on Twitter

Monkey CDEV
Volume Number:3
Issue Number:9
Column Tag:C Workshop

CDEV Extends Control Panel

By Jan Eugenides, Assembly Corner, Maynard, MA

The new control panel that comes with System 4.1 is extensible. You can write a code resource called a ‘cdev’ to add functions to the control panel. The process is not difficult, and it offers a number of interesting possibilities.

What I had in mind for this project was to write a fairly simple cdev, just to test the waters. Having just acquired a Macintosh II, I also wanted to explore some of the sound generation capabilities. The result is Monkey, an amusing addition to the control panel. Although this particular cdev will only work on a Macintosh II (because it calls the Mac II’s sound routines), the techniques shown here will work for more generalized cdevs as well.

The Control Panel

Figure 1 shows the new Control Panel with the General panel displayed. The panel allows choosing the Desktop pattern, setting the rate of insertion point blinking, setting the time, and more. Some other standard panels allow setting keyboard options, sound options, and display options.

By writing your own cdev, you can add a new icon to the scrollable list that appears on the left edge of the Control Panel. In Figure 1, you can see the icon for the Monkey cdev at the bottom. Clicking on an icon selects it, and the Control Panel displays various controls, depending on the item list contained in the corresponding cdev. Figure 2 shows how the Control Panel appears when Monkey is selected. Clicking on the picture of a monkey causes the Macintosh II to generate the a monkey screech sound.

How It Works

When the user opens the Control Panel, it scans the System Folder for all resource files of type ‘cdev’. When it finds one, it loads the icon and the file’s name and adds it to the icon list. After all the cdevs are loaded, the General icon is selected and the standard controls are displayed. The Control Panel then calls the cdev with various event messages, indicating which items the user has clicked or dragged, enabling the cdev to track its controls.

A cdev file must contain eight resources:

• cdev - a code resource

• mach - some data that indicates which machines the cdev is compatible with

• DITL - a standard Dialog item list

• nrct - some data that defines the number of rectangles needed for the cdev’s display, and their sizes.

• ICN# - a standard icon with mask

• BNDL - a standard bundle resource

• FREF - a standard file reference resource

• An owner resource, that must be a unique four-character identifier, just like the ones used for applications. The Monkey cdev uses the type ‘mOnk’.

With the exception of the owner resource, all the resources should have the same ID number, -4064. The owner resource ID depends on how the BNDL is structured, and is usually zero.

Fig. 1 Adding our own control functions

The nrct and mach Resources

These two resources are unique to cdevs, and require some more detailed explanation. The nrct type is a list of rectangles. The first word of the resource is the number of rectangles in the list. It is followed by eight bytes for each rectangle, which describe the top, left, bottom, and right boundaries. For each rectangle defined in the nrct, the Control Panel clears out some white space in its window, and draws a frame around it. The nrct, along with the DITL, define the look of the cdev panel.

The mach resource type consists of two words. The first is called the Softmask, and is compared to the global variable ROM85 to determine which toolbox features are available (such as Color Quickdraw). The second word is called the Hardmask, and it is used to determine which hardware features are available. The values of these masks determines on which machines the cdev will appear. Table 1 shows some possible settings.

The cdev code

Listing 1 shows the code used in the Monkey cdev, written in LightspeedC. The main function is declared as:

pascal  Handle main(message,item,numItems,CPanelID,ep,cdevStorage, CPDialog)
intmessage,item,numItems,CPanelID;
EventRecord *ep;
Handle  cdevStorage;
DialogPtr CPDialog;

Message is a number that tells the cdev what event just took place. Monkey only responds to three types of messages: initDev, which means “do your initialization”; closeDev, which means “dispose of any allocated storage and close up shop”; and hitDev, which means “the user clicked on an item”.

For initDev, Monkey just allocates 16 bytes of storage, and returns the handle in cdevStorage. Monkey does not use this storage, but the Control Panel wants to see a valid handle. For closeDev, Monkey releases the 16 bytes of storage, and clears the cdevStorage variable. For hitDev, Monkey loads the ‘snd ’ resource with ID# 4 (the monkey screech),and then calls the Macintosh II Sound Manager routine SndPlay to generate the sound. Since there is only one item, the DoHit routine does not have to determine which item was clicked on. If there were more items, the DoHit routine would have to subtract numItems from item to determine which item in its DITL was clicked. This is because the cdev’s DITL is appended to the Control Panel’s DITL.

Fig. 2 Our Monkey Squeek!

Compiling the cdev in LightspeedC

Creating the Monkey cdev is fairly straightforward in LightspeedC. First use RMaker to compile the necessary resources, as given in Listing 3. Create a new project called MonkeyCdevP, and set the project type to a code resource of type cdev. Enter Listing 2, and save it as SoundMgr.h, in the same folder with your other Macintosh header files. Add the MacTraps library to the project. Enter Listing 1, save it as MonkeyCdev.c and add it to the project. Then build the code resource (select Build Code Resource from the Project menu). Save it as Monkey. Finally, use ResEdit to set the creator type to mOnk, and set the bundle bit. Now drag the finished cdev into the System Folder, open the Control Panel, and make the monkey screech!

A Note About the Resources

I didn’t actually use RMaker to create the resources for the Monkey cdev. I created them with ResEdit, and then used a shareware resource decompiler called ResDecomp, by Robert Comer, to create the RMaker source code for publication. To save yourself some typing, you may want to create your own ICN# and PICT resources using ResEdit, rather than enter all the hex code for them. Just be sure to give them the correct ID numbers, and make them purgeable.

By the way, the monkey picture was originally taken from a clip art disk called WetPaint, put out by Dubl-Clik software. I modified it some, but I like to give credit for these things.

Table 1: Sample mach Settings

Softmask Hardmask Function

$0000 $FFFF call cdev to determine whether it should show up

$FFFF $0000 show up on all machines

$7FFF $0400 show up on machines with an Apple Desktop Bus only

$3FFF $0000 show up on the Macintosh II only

Listing 1.
/* Monkey CDEV
 * by Jan Eugenides
 * 6/6/87
 *
 * An example of adding a function to the
 * Control Panel, and using the Macintosh II’s
 * SndPlay routine
 */
#include <MacTypes.h>
#include <pascal.h>
#include <MemoryMgr.h>
#include <OSUtil.h>
#include <ToolboxUtil.h>
#include <DialogMgr.h>
#include <EventMgr.h>
#include <SoundMgr.h>
/*First define some needed constants*/
enum{
 initDev,
 hitDev,
 closeDev,
 nulDev,
 updateDev,
 deActivDev,
 keyEvtDev,
 macDev
 };
 
 Handle InitStorage();
 
 /*This is main routine, entry point for the CDEV*/
 pascal Handle main(message,item,numItems,CPanelID,ep,cdevStorage,CPDialog)
 int    message,item,numItems,CPanelID;
 EventRecord*ep;
 Handle cdevStorage;
 DialogPtrCPDialog;
 {
 if(message == macDev)return((Handle)1);
 if(cdevStorage)
 {
 switch(message)
 {
 case initDev: /*Init message received, 
 allocate some storage*/
 cdevStorage = InitStorage();
 if(cdevStorage)DoHit(1+numItems, numItems,CPDialog);
 break;
 case closeDev: /*Close message received, dispose of           
 storage*/
 DisposeStorage(cdevStorage);
 cdevStorage = (Handle)0L;
 break;
 case hitDev: /*User clicked an item, handle it*/
 DoHit(item,numItems,CPDialog);
 break;
 } /*end switch*/
 } /*end else if*/ 
return(cdevStorage);
 }
  Handle  InitStorage()  /*ultra-simple storage allocation*/
 { /*The storage is not used in this example*/
 return(NewHandle(16L));
 }
 
 DisposeStorage(h) /*Release our storage area*/
 Handle h;
 {
 DisposHandle(h);
 }
 
 DoHit(item,numItems,CPDialog)/*Handle a click on one of       
 our items*/
 int  item,numItems;   /*This example has one item, so it’s*/
 DialogPtrCPDialog;  /*very simple*/
 {
 Handle soundH;
 
soundH = GetResource(‘snd ‘,4);/*there is a space after snd */
if(soundH)
 SndPlay(0L,soundH,TRUE);   /*play the monkey screech*/
}

* Resources for Monkey cdev

MonkeyCdevP.rsrc
\00\00\00\00\00\00\00\00

Type ICN# = GNRL
 ,-4064 (32) ;; attributes -> Purgeable
.H
00000000 0000FE00 0003FF80 000F01E0
0F9C007F 1FF9C7BF 3AF7FFDA 7FEE3C6F
6AEC992E 7FCDDBB7 6ACD99B6 7FCC0037
6AC60066 3FC4FF27 3BC1FF87 1FE3D7CF
0F67FFED 00363C78 003C003D 001DFFB0
000DC3B5 000C4230 00077E75 001F00E0
003DFFD5 0078FF08 00F57555 01E2B000
03D57555 07E8F080 0DF5F555 1FFFB000
00000000 0000FE00 0003FF80 000FFFE0
0F9FFFFF 1FFFFFFF 3FFFFFFE 7FFFFFFF
7FFFFFFE 7FFFFFFF 7FFFFFFE 7FFFFFFF
7FFFFFFE 3FFFFFFF 3FFFFFFF 1FFFFFFF
0F7FFFFD 003FFFF8 003FFFFD 001FFFF0
000FFFF5 000FFFF0 0007FFF5 001FFFE0
003FFFD5 007FFF08 00FFF555 01FFF000
03FFF555 07FFF080 0FFFF555 1FFFB000

Type FREF
 ,-4064 (32) ;; attributes -> Purgeable
cdev 0 

Type BNDL
 ,-4064 (32) ;; attributes -> Purgeable
mOnk 0
ICN#
 0 -4064 
FREF
 0 -4064 

Type DITL
 ,-4064 (32) ;; attributes -> Purgeable
2

PicItem
1 128 76 194
-4064

StatText Disabled
77 133 93 206
Click Me!

Type PICT = GNRL
 ,-4064 (32) ;; attributes -> Purgeable
.H
03850000 0000004B 00421101 01000A00
00000000 4B004298 000A0031 0066007C
00A80031 0066007C 00A80000 0000004B
00420000 08FC0002 01FFF0FF 0008FC00
0203FFFC FF0008FC 000206AA AAFF0008
FC00020F F7F7FF00 08FC0002 0AAAABFF
0008FC00 020FFFFF FF0008FC 00040BFF
AA800008 FC000406 00FF8000 06FA0002
2A800006 FA00023F 800006FA 00021AC0
000A0200 00FEFD00 0217C000 0B030003
FF80FE00 021AC000 0B03000F 01E0FE00
021FC000 0B090F9C 007FC000 001AC000
0B091FF9 C7BFF000 001F4000 0B093AF7
FFDAB800 001AC000 0B097FEE 3C6FFC00
001FC000 0B096AEC 992EAC00 001AC000
0B097FCD DBB7FC00 0017C000 0B096ACD
99B6AC00 001AC000 0B097FCC 0037FC00
001FC000 0B096AC6 0066B800 001AC000
0B093FC4 FF27F800 001F4000 0B093BC1
FF87FFC0 001AC000 0B091FE3 D7CFFFF8
001FC000 0B090F67 FFED557F 001AC000
0B090036 3C78080F C0178000 0B09003C
003D5555 F01A8000 0B09001D FFB00000
7C3F8000 0B09000D C3B55555 5E2A8000
0B09000C 42308080 87BF8000 0B030007
7E75FE55 02EA8000 0B03001F 00E0FE00
02FF8000 0B03003D FFD5FE55 027A8000
0A020078 FFFD0802 3F80000A 0200F575
FD55025A 80000A02 01E2B0FD 00021F80
000A0203 D575FD55 025E8000 0A0207E8
F0FD8002 8F80000A 020DF5F5 FD55025F
00000A02 1FFFB0FD 00020700 000A023A
AF35FD55 02570000 0A027FFE 78FD0802
0F00000A 02777C75 FD550257 00000A02
FFF860FD 00020300 000A02EA B075FD55
02570000 0B09FFE0 6080FE80 80830000
0B09DDC0 7557FFD5 55570000 0B09FF80
C0073BC0 00030000 0B09EF00 D55E35F5
55570000 0B097E00 C81C38F8 080B0000
0B073800 D558357D 5557FF00 0B070000
C03032BC 0003FF00 0B070001 D570755D
5557FF00 0B070001 80E0688E 8083FF00
0B070001 D560755F 5557FF00 0B070003
80C06A3B 0003FF00 0B070003 D5C0D55B
5557FF00 0B070003 0980C8B1 880BFF00
0B070007 5580D571 D557FF00 0B070006
0300E2E0 C003FF00 0B070007 5700D560
D557FF00 0B07000E 860188C0 6083FF00
0B07000F 5601D5C0 7556FF00 0B07001C
0C01AB80 3006FF00 0B07001F FC01FF80
1FFEFF00 0B07003F F803FF00 1FFEFF00
0B090077 78037700 0F760000 0B0901FF
F807FF00 0FFE0000 0B097FEA B9FEAB0F
FEAE0000 0B09FFFF FBFFFF1F FFFE0000
0B09DDDD FBDDDF1D DDDE0000 0B09FFFF
F3FFFF1F FFFE0000 0B097FFF E1FFFE0F
FFFC0000 FF

Type mOnk = GNRL
 ,-4064 (32) ;; attributes -> Purgeable
.H
1C4D6F6E 6B657920 63646576 20627920
4A616E20 45756765 6E696465 73

Type nrct = GNRL
 ,-4064
.H
0001FFFF 00570066 00CE

Type mach = GNRL
 ,-4064 (32) ;; attributes -> Purgeable
.H
3FFF0000 
 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Latest Forum Discussions

See All

Six fantastic ways to spend National Vid...
As if anyone needed an excuse to play games today, I am about to give you one: it is National Video Games Day. A day for us to play games, like we no doubt do every day. Let’s not look a gift horse in the mouth. Instead, feast your eyes on this... | Read more »
Old School RuneScape players turn out in...
The sheer leap in technological advancements in our lifetime has been mind-blowing. We went from Commodore 64s to VR glasses in what feels like a heartbeat, but more importantly, the internet. It can be a dark mess, but it also brought hundreds of... | Read more »
Today's Best Mobile Game Discounts...
Every day, we pick out a curated list of the best mobile discounts on the App Store and post them here. This list won't be comprehensive, but it every game on it is recommended. Feel free to check out the coverage we did on them in the links below... | Read more »
Nintendo and The Pokémon Company's...
Unless you have been living under a rock, you know that Nintendo has been locked in an epic battle with Pocketpair, creator of the obvious Pokémon rip-off Palworld. Nintendo often resorts to legal retaliation at the drop of a hat, but it seems this... | Read more »
Apple exclusive mobile games don’t make...
If you are a gamer on phones, no doubt you have been as distressed as I am on one huge sticking point: exclusivity. For years, Xbox and PlayStation have done battle, and before this was the Sega Genesis and the Nintendo NES. On console, it makes... | Read more »
Regionally exclusive events make no sens...
Last week, over on our sister site AppSpy, I babbled excitedly about the Pokémon GO Safari Days event. You can get nine Eevees with an explorer hat per day. Or, can you? Specifically, you, reader. Do you have the time or funds to possibly fly for... | Read more »
As Jon Bellamy defends his choice to can...
Back in March, Jagex announced the appointment of a new CEO, Jon Bellamy. Mr Bellamy then decided to almost immediately paint a huge target on his back by cancelling the Runescapes Pride event. This led to widespread condemnation about his perceived... | Read more »
Marvel Contest of Champions adds two mor...
When I saw the latest two Marvel Contest of Champions characters, I scoffed. Mr Knight and Silver Samurai, thought I, they are running out of good choices. Then I realised no, I was being far too cynical. This is one of the things that games do best... | Read more »
Grass is green, and water is wet: Pokémo...
It must be a day that ends in Y, because Pokémon Trading Card Game Pocket has kicked off its Zoroark Drop Event. Here you can get a promo version of another card, and look forward to the next Wonder Pick Event and the next Mass Outbreak that will be... | Read more »
Enter the Gungeon review
It took me a minute to get around to reviewing this game for a couple of very good reasons. The first is that Enter the Gungeon's style of roguelike bullet-hell action is teetering on the edge of being straight-up malicious, which made getting... | Read more »

Price Scanner via MacPrices.net

Take $150 off every Apple 11-inch M3 iPad Air
Amazon is offering a $150 discount on 11-inch M3 WiFi iPad Airs right now. Shipping is free: – 11″ 128GB M3 WiFi iPad Air: $449, $150 off – 11″ 256GB M3 WiFi iPad Air: $549, $150 off – 11″ 512GB M3... Read more
Apple iPad minis back on sale for $100 off MS...
Amazon is offering $100 discounts (up to 20% off) on Apple’s newest 2024 WiFi iPad minis, each with free shipping. These are the lowest prices available for new minis among the Apple retailers we... Read more
Apple’s 16-inch M4 Max MacBook Pros are on sa...
Amazon has 16-inch M4 Max MacBook Pros (Silver and Black colors) on sale for up to $410 off Apple’s MSRP right now. Shipping is free. Be sure to select Amazon as the seller, rather than a third-party... Read more
Red Pocket Mobile is offering a $150 rebate o...
Red Pocket Mobile has new Apple iPhone 17’s on sale for $150 off MSRP when you switch and open up a new line of service. Red Pocket Mobile is a nationwide MVNO using all the major wireless carrier... Read more
Switch to Verizon, and get any iPhone 16 for...
With yesterday’s introduction of the new iPhone 17 models, Verizon responded by running “on us” promos across much of the iPhone 16 lineup: iPhone 16 and 16 Plus show as $0/mo for 36 months with bill... Read more
Here is a summary of the new features in Appl...
Apple’s September 2025 event introduced major updates across its most popular product lines, focusing on health, performance, and design breakthroughs. The AirPods Pro 3 now feature best-in-class... Read more
Apple’s Smartphone Lineup Could Use A Touch o...
COMMENTARY – Whatever happened to the old adage, “less is more”? Apple’s smartphone lineup. — which is due for its annual refresh either this month or next (possibly at an Apple Event on September 9... Read more
Take $50 off every 11th-generation A16 WiFi i...
Amazon has Apple’s 11th-generation A16 WiFi iPads in stock on sale for $50 off MSRP right now. Shipping is free: – 11″ 11th-generation 128GB WiFi iPads: $299 $50 off MSRP – 11″ 11th-generation 256GB... Read more
Sunday Sale: 14-inch M4 MacBook Pros for up t...
Don’t pay full price! Amazon has Apple’s 14-inch M4 MacBook Pros (Silver and Black colors) on sale for up to $220 off MSRP right now. Shipping is free. Be sure to select Amazon as the seller, rather... Read more
Mac mini with M4 Pro CPU back on sale for $12...
B&H Photo has Apple’s Mac mini with the M4 Pro CPU back on sale for $1259, $140 off MSRP. B&H offers free 1-2 day shipping to most US addresses: – Mac mini M4 Pro CPU (24GB/512GB): $1259, $... Read more

Jobs Board

All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.