TweetFollow Us on Twitter

June 1994 - Graphical Truffles

Graphical Truffles

The Debugging Version of QuickDraw GX

Pete ("Luke") Alexander

By now, many of you have installed one of the beta versions of QuickDraw GX onto your Macintosh -- and possibly by the time you read this, QuickDraw GX Software Developer's Kit version 1.0 will be available from APDA. Maybe you've played with the various sample applications and are now ready to work on your first QuickDraw GX application. Perhaps you've even read my article in develop; Issue 15, "Getting Started With QuickDraw GX." In this column, I'll talk about something I referred to briefly in that article: the two versions of QuickDraw GX's combined graphics and layout portions, and how to take advantage of the debugging version during the development of your QuickDraw GX-based application. Along the way I'll update you on a few changes since I wrote the article.

THE EXTENSIONS OF QUICKDRAW GX
The QuickDraw GX system extension comes in two flavors: a nondebugging and a debugging version. When you run the QuickDraw GX installer script, the nondebugging version is installed, including the complete QuickDraw GX system. The nondebugging version is lean and mean, so it's significantly faster than the debugging version; it performs quite a bit less error checking than the debugging version.

The debugging version of the extension provides extensive error checking and other debugging amenities. When developing a QuickDraw GX application, you should use this version to shake out the bugs. The debugging extension is in the DEBUG Init folder and is named "GXGraphics (debug)" in version 1.0 (it used to be named aSecretGraphics.debug); just drag it into your System Folder and reboot. As your system starts up you'll see the debugging extension's icon displayed before the QuickDraw GX icon.

An explanation of what's really going on here may help clarify things (and it has changed): There are actually three extensions within the QuickDraw GX extension -- one for graphics and layout, one for printing, and one for the Finder printing extension. The QuickDraw GX extension knows, if "GXGraphics (debug)" has already loaded, to use that extension instead of the nondebugging version of the graphics and layout extension. (Note that since the debugging extension must load before the nondebugging version, you should not change the debugging extension's name.)

THE ADVANTAGES OF THE DEBUGGING VERSION DURING DEVELOPMENT
Let's look at some differences between the two extensions, and specifically how to take advantage of the debugging version during the development of your QuickDraw GX application.

Notices, warnings, and errors. With the debugging version of the extension, you can get three types of information about drawing problems: notices, warnings, and errors. For a complete list of these, look at the graphics errors.h interface file. The many notices, warnings, and errors defined between #ifdef debugging and #endif in that file are available only with the debugging version. You'll need to #define debugging in your application to take advantage of them. (Make sure debugging is not defined when you build your final version.)

With the nondebugging version, notices aren't available at all, and the list of errors and warnings you need to respond to in your application consists only of those relatively few that lie outside #ifdef debugging and #endif in the graphics errors.h file. Your application must be set up to handle these errors and warnings, which in general indicate that the QuickDraw GX system could not honor your application's request. For example:

shape_is_nil
size_of_path_exceeds_implementation_limit
picture_index_out_of_range

The debugging version checks for errors that you're likely to run into while developing your application, such as passing a negative pen size to GXSetShapePen or a curve to GXGetGlyphMetrics. The nondebugging version doesn't check for these types of errors; it assumes you've already shaken them out of the code.

Validation routines. The GXSetValidation and GXValidateShape routines are available only in the debugging version. These routines allow your application to tell whether it's passing valid parameters into a QuickDraw GX function, to validate the contents of all QuickDraw GX objects (such as a shape, style, and ink) before their use, and to validate the QuickDraw GX memory your application is using.

Speed optimizations. The nondebugging version has optimizations for speed built in -- not only fewer error checks but also inline functions. The debugging version doesn't optimize for speed. This shouldn't have any impact on your application development except that there's not a one-to-one correspondence between stack crawls using the debugging and nondebugging versions. A performance analysis of your QuickDraw GX application should only be donewithout the "GXGraphics (debug)" file in your Extensions folder.

GraphicsBug. The GraphicsBug debugging tool allows you to explore the contents of any QuickDraw GX object to make sure it contains the correct information. Another change from before is that GraphicsBug is available in both the debugging and nondebugging versions. This ability to spy on an object's contents is important to your application development because otherwise you could only access information in objects by making API calls, which would be very tedious during debugging.

There's a slight advantage when using GraphicsBug with the debugging version: heaps are listed by name rather than by hex address in the Heaps menu.

Memory. The debugging version's memory blocks in the QuickDraw GX heap are a bit bigger to help detect errors when your application writes over the end of a block: all the blocks end with the same signature, 'grfx'.

Special MacsBug messages. The debugging version generates MacsBug messages that are intended solely for the consumption of the Apple engineers in unusual circumstances. (One of my favorites is "Curious if this ever happens.") If we did our jobs right, you should never see one of these messages. In case you do, however, we're really interested in hearing what caused you to receive it; please let us know at AppleLink APPLE.BUGS.

CLEANING UP
You should design your application to take advantage of the extensive capabilities of the debugging extension, but turn those capabilities off when you create your final shipping application, to improve its performance. For example, calling GXValidateShape with the nondebugging extension installed will only result in a jump and return (that is, it will be a no-op). This is a wonderful method for testing the QuickDraw GX dispatcher, but it doesn't help the performance of your application.

In the final compile of your shipping application, you'll most likely want to remove all calls to validation routines, posting of notices, and extra warnings and errors available only in the debugging version. One approach would be to have various compilation flags associated with pairs of #ifdef and #endif to turn these features on and off.

For more information, see my article in Issue 15 if you haven't already -- or just dig into the QuickDraw GX documentation. Enjoy your journey into the QuickDraw GX world!

RELATED READING

  • "Getting Started With QuickDraw GX" by Pete ("Luke") Alexander, develop  Issue 15.
  • "Print Hints: Looking Ahead to QuickDraw GX" by Pete ("Luke") Alexander, develop  Issue 13.

PETE ("LUKE") ALEXANDER has been providing developer support for QuickDraw GX ever since it was way up in the air. He's happy it's making its final approach, and he's hoping it lands smack dab in the middle of your software. As a glider pilot, Luke knows how important control is -- and with QuickDraw GX, you'll be able to maneuver your software into spaces you never thought possible. Since QuickDraw GX can help you do lots of great graphics stunts that you used to have to ask him about, Luke is about to soar off into the wild blue yonder and do some stunts of his own. Soon he'll be ready for the preflight check that will launch his sabbatical faster than QuickDraw GX handles two-byte text. For many weeks he'll be thinking about nothing but white sand beaches, white puffy clouds, and white-capped mountains. He'll lie on his back and watch the sway of the trees until they stop reminding him of the swashes of L's. So if you see him somewhere in Montana, Utah, Nevada, California, or Idaho, be sure to say hello -- but try not to use any words that have a G and an X in them. *

Thanks to Hugo Ayala, Cary Clark, and Herb Derby for reviewing this column. *

 
AAPL
$104.87
Apple Inc.
+1.88
MSFT
$44.74
Microsoft Corpora
+0.36
GOOG
$543.85
Google Inc.
+11.14

MacTech Search:
Community Search:

Software Updates via MacUpdate

jAlbum Pro 12.2.4 - Organize your digita...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code!... Read more
jAlbum 12.2.4 - Create custom photo gall...
With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly, with pro results Simply drag and drop photos into groups, choose a design... Read more
ExpanDrive 4.1.7 - Access remote files o...
ExpanDrive builds cloud storage in every application, acts just like a USB drive plugged into your Mac. With ExpanDrive, you can securely access any remote file server directly from the Finder or... Read more
OmniOutliner Pro 4.1.3 - Pro version of...
OmniOutliner Pro is a flexible program for creating, collecting, and organizing information. Give your creativity a kick start by using an application that's actually designed to help you think. It'... Read more
Evernote 5.6.2 - 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
OmniOutliner 4.1.3 - Organize your ideas...
OmniOutliner is a flexible program for creating, collecting, and organizing information. Give your creativity a kick start by using an application that's actually designed to help you think. It's... Read more
BBEdit 11.0 - Powerful text and HTML edi...
BBEdit is the leading professional HTML and text editor for the Mac. Specifically crafted in response to the needs of Web authors and software developers, this award-winning product provides a... Read more
Apple Security Update 2014-005 - For OS...
Apple Security Update is recommended for all users and improves the security of Mac OS X. For information on the security content of this update, please visit this website: http://support.apple.com/... Read more
EyeTV 3.6.6 - Watch and record TV on you...
EyeTV brings a rich TV experience to your Mac. Watch live TV on your Mac. Pause, rewind, and record whenever you want. EyeTV gives you powerful control over what you watch and how you watch it. Put... Read more
RapidWeaver 6.0 - Create template-based...
RapidWeaver is a next-generation Web design application to help you easily create professional-looking Web sites in minutes. No knowledge of complex code is required, RapidWeaver will take care of... Read more

Latest Forum Discussions

See All

Build Your Own Fantasy Football Dynasty...
Build Your Own Fantasy Football Dynasty with Draft Day Posted by Jessica Fisher on October 23rd, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Jam Messenger Review
Jam Messenger Review By Jennifer Allen on October 23rd, 2014 Our Rating: :: SIMPLE MESSAGINGiPhone App - Designed for the iPhone, compatible with the iPad Want a very quick way to send push-based messages? Jam Messenger is basic... | Read more »
Felllice (Games)
Felllice 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: EXCLUSIVE PRICE DROP! 50% OFF FOR A LIMITED TIME! EAT EAT EAT AND GROW ! | Read more »
The Arrow Game: by Grazie Media (Games)
The Arrow Game: by Grazie Media 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: Guide a flying arrow through skyscrapers and city streets to hit a distant target. Experience an endless... | Read more »
Worldly (Games)
Worldly 1.2 Device: iOS Universal Category: Games Price: $2.99, Version: 1.2 (iTunes) Description: | Read more »
Money Pro - EASY! Bills, Budgets and Acc...
Money Pro - EASY! Bills, Budgets and Accounts w/ Sync 1.0 Device: iOS Universal Category: Finance Price: $4.99, Version: 1.0 (iTunes) Description: Manage money like a pro. Money Pro is the next generation of Money app (over 2 million... | Read more »
Pro Strategy Football 2014 (Games)
Pro Strategy Football 2014 2014.141001 Device: iOS Universal Category: Games Price: $4.99, Version: 2014.141001 (iTunes) Description: Take the proven strategy of the PSF franchise and add in Casual Play, improved graphics and... | Read more »
Super Glyph Quest (Games)
Super Glyph Quest 1.01 Device: iOS Universal Category: Games Price: $2.99, Version: 1.01 (iTunes) Description: Adventure is back Questers! Combine elemental glyphs together to cast powerful spells and vanquish adorable monsters in... | Read more »
Fighting Fantasy: Caverns of the Snow Wi...
Fighting Fantasy: Caverns of the Snow Witch 1.0 Device: iOS Universal Category: Games Price: $5.99, Version: 1.0 (iTunes) Description: Travel to Northern Allansia’s perilous Icefinger Mountains to defeat the wicked Snow Witch in this... | Read more »
Star Warfare 2: Payback Review
Star Warfare 2: Payback Review By Blake Grundman on October 22nd, 2014 Our Rating: :: ONE-TRICK PONYUniversal App - Designed for iPhone and iPad Unfortunately, it doesn’t take long for Star Warfare 2’s free-firing fun to turn into... | Read more »

Price Scanner via MacPrices.net

Apple refurbished Time Capsules available sta...
The Apple Store has certified refurbished Time Capsules available for up to $60 off MSRP. Apple’s one-year warranty is included with each Time Capsule, and shipping is free: - 2TB Time Capsule: $255... Read more
Textilus New Word, Notes and PDF Processor fo...
Textilus is new word-crunching, notes, and PDF processor designed exclusively for the iPad. I haven’t had time to thoroughly check it out yet, but it looks great and early reviews are positive.... Read more
WD My Passport Pro Bus-Powered Thunderbolt RA...
WD’s My Passport Pro RAID solution is powered by an integrated Thunderbolt cable for true portability and speeds as high as 233 MB/s. HighlightsOverviewSpecifications Transfer, Back Up And Edit In... Read more
Save with Best Buy’s College Student Deals
Take an additional $50 off all MacBooks and iMacs at Best Buy Online with their College Students Deals Savings, valid through November 1st. Anyone with a valid .EDU email address can take advantage... Read more
iPad Air 2 & iPad mini 3 Best Tablets Yet...
The new iPads turned out to be pretty much everything I’d been hoping for and more than I’d expected.”More” particularly in terms of a drinking-from-a-firehose choice of models and configurations,... Read more
Drafts 4 Reinvents iOS Productivity App
N Richland Hills, Texas based Agile Tortoise has announced the release of Drafts 4 for iPhone and iPad. Drafts is a quick capture note taking app with flexible output actions. Drafts 4 scales from... Read more
AT&T accepting preorders for new iPads fo...
AT&T Wireless is accepting preorders for the new iPad Air 2 and iPad mini 3, cellular models, for $100 off MSRP with a 2-year service agreement: - 16GB iPad Air 2 WiFi + Cellular: $529.99 - 64GB... Read more
Apple offering refurbished Mac Pros for up to...
The Apple Store is offering Apple Certified Refurbished 2013 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
Select MacBook Airs $100 off MSRP, free shipp...
B&H Photo has 2014 a couple of MacBook Airs on sale for $100 off MSRP. Shipping is free, and B&H charges NY sales tax only. They also include free copies of Parallels Desktop and LoJack for... Read more
13-inch 2.5GHz MacBook Pro on sale for $100 o...
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

Jobs Board

Senior Event Manager, *Apple* Retail Market...
…This senior level position is responsible for leading and imagining the Apple Retail Team's global event strategy. Delivering an overarching brand story; in-store, Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
Project Manager / Business Analyst, WW *Appl...
…a senior project manager / business analyst to work within our Worldwide Apple Fulfillment Operations and the Business Process Re-engineering team. This role will work Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Position Opening at *Apple* - Apple (United...
…customers purchase our products, you're the one who helps them get more out of their new Apple technology. Your day in the Apple Store is filled with a range of Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.