TweetFollow Us on Twitter

Jun 95 Tips
Volume Number:11
Issue Number:6
Column Tag:Tips & Tidbits

Tips & Tidbits

By Neil Ticktin, Editor-in-Chief with special thanks to Steve Sisak

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.

TIP OF THE MONTH

GetKeys From Within MacsBug

There is a routine in the Macintosh toolbox called GetKeys. This routine is great for game programmers who want a reasonably fast way to read the keyboard, without using (slower) events. The problem for C and C++ programmers using this routine is that the KeyMap type is a Pascal packed array. Each bit of the packed array is designated to a certain key, the bit is set to 1 if the key is down, and set to zero if the key is up. This array takes up 16 bytes (128 bits). C cannot access the elements of the packed array like a normal array, so the programmer has to mask out some bits to get the result that he/she wants. There is a desk accessory named “GetKeys,” that is made just for this case. The problem is, you might not be on a machine with that program on it.

Good thing MacsBug is able to help us. Here is how you locate the bit for the letter “M”: go into MacsBug and type in “dm KeyMap”, but don’t hit return just yet. Now strike the escape key, this should swap the screen. Press and hold down the letter “M” on your keyboard, this should swap the screen back. Now, while still holding down “M”, press return. This is what you should see:

Displaying memory from 0174:

  00000174  0000 0000 0040 0000  0000 0000 0000 0000       •••••@••••••••••

The number “00000174” is the address of the KeyMap global variable. The next set of numbers “0000 0000” is the first element of the C version of the array, in other words it’s: “keyMap[0]”. The next set of numbers “0040 0000” is the second element of the array, keyMap[1]. The next group of 8 hexadecimal digits is the third element (keyMap[2]), and the last group of 8 hexadecimal digits is the fourth element (keyMap[3]). The series of bullets is what the array looks like in ASCII form. In the second group (“0040 0000”) there is a 4 in the midst of all of those zeros. This is the bit that is set to 1 whenever the “M” key is held down. So, to see if the “M” is down from within C we will do this:

 KeyMap keyMap;
 GetKeys( keyMap );

 if( keyMap[1] & 0x00400000 )
 {  DoMKeyDown();
 }

That’s all there is to it!

Macneil Shonle, Yarmouth Maine
MacneilS@aol.com

Almost, But Not Quite

In his tip (MacTech, March 1995 issue, page 67), Jeff Beeghly assumes items #1 and #2 to be respectively the default and the cancel items. That is not always true: in fact these may even change between subsequent calls to the same dialog/alert if the programmer used “SetDialogDefaultItem” and “SetDialogCancelItem” before calling ModalDialog or set the “ALRT stage info” in ResEdit for the alert box. The safest way to find the default item is to look at the “aDefItem” field of the DialogRecord that is passed to the the custom modal filter procedure.

Moreover, I think it is best to let the original filter procedure track standard events we’re not interested in, by calling it via “StdFilterProc” from our custom filter proc and then returning its return value to the application.

- Luigi Belverato

 
AAPL
$101.58
Apple Inc.
+0.72
MSFT
$46.52
Microsoft Corpora
-0.24
GOOG
$584.77
Google Inc.
+4.82

MacTech Search:
Community Search:

Software Updates via MacUpdate

iExplorer 3.5.0.0 - View and transfer al...
iExplorer is an iPhone browser for Mac lets you view the files on your iOS device. By using a drag and drop interface, you can quickly copy files and folders between your Mac and your iPhone or... Read more
BusyCal 2.6 - Powerful calendar app with...
BusyCal is an award-winning desktop calendar that combines personal productivity features for individuals with powerful calendar sharing capabilities for families and workgroups. BusyCal's unique... Read more
Apple iOS 8.0 - The latest version of Ap...
The latest version of iOS can be downloaded through iTunes. Apple iOS 8 comes with big updates to apps you use every day, like Messages and Photos. A whole new way to share content with your family.... Read more
Apple Digital Camera RAW Compatibility 5...
Apple Digital Camera RAW Compatibility update adds RAW image compatibility to Aperture 3 and iPhoto '11. For more information on supported RAW formats, see here.Version 5.07: Adds RAW camera... Read more
Transmit 4.4.7 - Excellent FTP/SFTP clie...
Transmit is an excellent FTP (file transfer protocol), SFTP, S3 (Amazon.com file hosting) and iDisk/WebDAV client that allows you to upload, download, and delete files over the internet. With the... Read more
Macgo Blu-ray Player 2.10.8.1715 - Blu-r...
Macgo Mac Blu-ray Player can bring you the most unforgettable Blu-ray experience on your Mac. Overview Macgo Mac Blu-ray Player can satisfy just about every need you could possibly have in a Blu-ray... Read more
Capture One Pro 8.0.0.433 - RAW workflow...
Capture One Pro 8 is a professional RAW converter offering you ultimate image quality with accurate colors and incredible detail from more than 300 high-end cameras -- straight out of the box. It... Read more
Adobe Acrobat Pro 11.0.09 - Powerful PDF...
Adobe Acrobat allows users to communicate and collaborate more effectively and securely. Unify a wide range of content in a single organized PDF Portfolio. Collaborate through electronic document... Read more
Adobe Reader 11.0.09 - View PDF document...
Adobe Reader allows users to view PDF documents. You may not know what a PDF file is, but you've probably come across one at some point. PDF files are used by companies and even the IRS to... Read more
iFFmpeg 4.6.1 - Convert multimedia files...
iFFmpeg is a graphical front-end for FFmpeg, a command-line tool used to convert multimedia files between formats. The command line instructions can be very hard to master/understand, so iFFmpeg does... Read more

Latest Forum Discussions

See All

Leg·end·ar·y (Games)
Leg·end·ar·y 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Simple and yet complex. Leg•end•dar•y is a grid-based puzzle game based on numbers. Discover the adventure of Leg•end•dar•y and... | Read more »
KuaiBoard (formerly QuickBoard) (Utilit...
KuaiBoard (formerly QuickBoard) 1.0 Device: iOS Universal Category: Utilities Price: $1.99, Version: 1.0 (iTunes) Description: KuaiBoard is currently 50% off for launch! Billing info. Signatures. Locations. KuaiBoard allows you to... | Read more »
Treasure Fetch - Adventure Time (Games)
Treasure Fetch - Adventure Time 1.0.1 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.1 (iTunes) Description: Adventure Time Treasure Fetch is a fresh take on the classic Snake game! STRETCHY JAKE Snake your way... | Read more »
Light in the Dark (Games)
Light in the Dark 1.1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.1.0 (iTunes) Description: Be enlightened by this delightful puzzle game that has never before seen the light of day! "A physics and color-blending... | Read more »
Transmit iOS (Utilities)
Transmit iOS 1.0 Device: iOS Universal Category: Utilities Price: $9.99, Version: 1.0 (iTunes) Description: >> LAUNCH SPECIAL: Transmit iOS is ONLY $10 for a LIMITED TIME. << THE #1 FILE TRANSFER CLIENT FOR THE MAC NOW... | Read more »
Minuum - The Little Keyboard for Big Fin...
Minuum - The Little Keyboard for Big Fingers 1.0 Device: iOS iPhone Category: Utilities Price: $1.99, Version: 1.0 (iTunes) Description: Type faster, see more of your screen, and take control of autocorrect with Minuum: the little... | Read more »
TextExpander 3 + custom keyboard (Utili...
TextExpander 3 + custom keyboard 3.0 Device: iOS Universal Category: Utilities Price: $4.99, Version: 3.0 (iTunes) Description: | Read more »
Swype - Keyboard (Utilities)
Swype - Keyboard 1.0.1411 Device: iOS Universal Category: Utilities Price: $.99, Version: 1.0.1411 (iTunes) Description: Why type when you can Swype? One of the most requested apps for iPhone is finally here. "If Swype itself ever... | Read more »
Joinz (Games)
Joinz 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Joinz is a clever block sliding puzzle game that is easy to play, nice to look at but tricky to master. You will be coming back again... | Read more »
Little World Escape Review
Little World Escape Review By Jordan Minor on September 17th, 2014 Our Rating: :: EARTHBOUNDUniversal App - Designed for iPhone and iPad Little World Escape draws players in with captivating concepts before pushing them away with... | Read more »

Price Scanner via MacPrices.net

Toshiba Introduces TransMemory ID High-Speed...
Toshiba’s Digital Products Division (DPD), a division of Toshiba America Information Systems, Inc., today introduced the TransMemory ID USB 3.0 Flash Drive, a simpler storage solution for people who... Read more
New iPads and OS X Yosemite Release Coming Oc...
The DailyDot’s Micah Singleton reports that Apple is planning to hold its next product announcement event on Oct. 21, at which it will unveil the iPad Air 2 and iPad mini 3 and release a final build... Read more
Logitech Bluetooth Multi-Device Cross-Platfor...
Logitech has an enviable track record of making some of the best computer keyboards and mice. At least in my estimation, the best freestanding keyboards I’ve ever used have been Logitech units,... Read more
Roundup of Apple refurbished iPad Airs and iP...
Apple is offering Certified Refurbished iPad Airs for up to $140 off MSRP. Apple’s one-year warranty is included with each model, and shipping is free. Stock tends to come and go with some of these... Read more
Sprint offers 16GB iPad mini for $199.99 with...
Sprint is offering 1st generation 16GB iPad minis for $199.99 with a 2-year service agreement. Standard MSRP for this iPad is $429. Their price is the lowest available for this model. Read more
2.5GHz Mac mini remains on sale for $549, sav...
B&H Photo has the 2.5GHz Mac mini on sale for $549.99 including free shipping. That’s $50 off MSRP, and B&H will also include a free copy of Parallels Desktop software. NY sales tax only. Read more
Apple refurbished iMacs available for up to $...
The Apple Store has Apple Certified Refurbished iMacs available for up to $300 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free. These are the best prices on... Read more
13″ 2.5GHz MacBook Pro offered for $100 off M...
B&H Photo has the 13″ 2.5GHz MacBook Pro on sale for $999.99 including free shipping plus NY sales tax only. Their price is $100 off MSRP. Read more
Free GIMP Professional Grade Graphics App Ver...
The latest 2.8.14 version of the oddly-named GIMP (acronym for: GNU Image Manipulation Program) open source, high-end image editing and creation alternative to Adobe’s Photoshop and refuge from... Read more
Apple Announces Record Pre-orders for iPhone...
Apple has released metrics showing a record number of first day pre-orders of iPhone 6 and iPhone 6 Plus, with over four million sold in the first 24 hours. Demand for the new iPhones exceeds 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* 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* 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* 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* 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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.