TweetFollow Us on Twitter

Winter 91 - SYS 7 Q&A

SYSTEM 7.0 Q & A

MACINTOSH DEVELOPER TECHNICAL SUPPORT

Q When I use the name and vRefNum returned from FindFolder, I always get a fnfErr from OpenRFPerm. Why?

A FindFolder returns both a vRefNum and a DirID. They both must be used to identify the folder. Instead of using OpenRFPerm,which takes only a vRefNum, try HOpenResFile. Avoid using PBHSetVol! (See Technical Note #140 for more information.)

Q We want to use OpenCPicture for higher resolution, not for color per se. Can OpenCPicture in System 7.0 be used with non-Color as well as Color QuickDraw Macintosh computers?

A Yes, with System 7.0, OpenCPicture can be used to create extended PICT2 files from all Macintosh computers. Under System 6.0.7 or later, you must test for 32-Bit QuickDraw before using OpenCPicture. You can do this by calling Gestalt with the gestaltQuickDrawVersion selector. If it returns gestalt32BitQD or greater, then 32-Bit QuickDraw is installed.Q Can the Communications Toolbox be used in a DA? InitCM has to be called and the manual says it should be called only once.

A Yes, it is all right to call CTB Initialization routines from CODE resources. This includes a DRVR, cdev, or INIT.

Q Can I use my 8*24 GC card with System 7.0ßx? I was told the GC misbehaves with any and all nonlinear address mapping, such as System 7.0 and A/UX. Is this true? Can this be fixed with CODE/INIT patch? Is it scheduled to be fixed in the near future?

A The 8*24 GC card software version 1.0 is not intended to run in any environment involving virtual memory management. A VM-compatible version of the GC software will be made available when System 7.0 is final. Until then, the card can be used as a video buffer, and System 7.0 preliminary software might run with VM switched off.Q Under what System 7.0 and System 6.0 conditions is it legal to call the QDError function?

A Under System 7.0, QDError can be called from all Macintosh computers. (System 7.0 supports RGBForeColor, RGBBackColor, GetForeColor, and GetBackColor for all Macintosh computers as well.) On a non-Color QuickDraw Macintosh, QDError always returns a "no error." Under System 6.0, QDError cannot be used for non-Color QuickDraw Macintosh systems.

Q Why do some CopyBits transfer modes produce different results for System 7.0 than for System 6.0?

A Under System 6.0, the srcOr, srcXor, srcBic, notSrcCopy, notSrcOr, notSrcXor, and notSrcBic transfer modes do not produce the same effect for a 16- or 32-bit (direct) pixel map as for an 8-bit or shallower (indexed) pixel map. With Color QuickDraw these classic transfer modes on direct pixel maps aren't color based; they're pixel value based. Color QuickDraw performs logical operations corresponding to the transfer mode on the source and destination pixel values to get the resulting pixel value.For example, say that a multicolored source is being copied onto a black and white destination using the srcOr transfer mode, and both the source and destination are 8 bits per pixel. Except in unusual cases, the pixel value for black on an indexed pixel map has all its bits set, so an 8-bit black pixel has a pixel value of $FF. Similarly, the pixel value for white has all its bits clear, so an 8-bit white pixel has a pixel value of $00. CopyBits takes each pixel value of the source and performs a logical OR with the corresponding pixel value of the destination. Using OR to combine any value with 0 results in the original value, so any pixel value ORed with the pixel value for white results in the original pixel value. Using OR to combine any value with 1 results in 1, so any pixel value ORed with the pixel value for black results in the pixel value for black. The resulting image shows the original image in all areas where the destination image was white and shows black in all areas where the destination image was black.

Take the same example, but this time make the source and destination 32 bits per pixel. The direct- color pixel value for black is $00000000 and the direct-color pixel value for white is $00FFFFFF. CopyBits still performs a logical OR on the source and destination pixel values, but notice what happens in this case. Using OR to combine any source pixel value with the pixel value for white results in white, and using OR to combine any source pixel value with the pixel value for black results in the original color. The resulting image shows the original image in all areas where the destination image was black and shows white in all areas where the destination image was white--roughly the opposite of what you see on an indexed pixel map.

The newer transfer modes addOver, addPin, subOver, subPin, adMax, and adMin work consistently at all pixel depths, and often, though not always, correspond to the theoretical effect of the old transfer modes. For example, the adMin mode works similarly to the srcOr mode on both direct and indexed pixel maps. Also, 1-bit deep source pixel maps work consistently and predictably regardless of the pixel depth of the destination even with the old transfer modes.

Under System Software 7.0, the old transfer modes now perform by calculating with colors rather than pixel values. You'll find that transfer modes like srcOr and srcBic work much more consistently even on direct pixel maps.

Q Is the Macintosh printing architecture different for System 7.0?

A No changes were made to the printing architecture for System 7.0. Printer drivers were revised for System 7.0 to support TrueType, to be completely 32-bit clean, and to fix bugs, but the printing architecture remains the same for System 7.0.Q BitMapToRegion does not work as described in Technical Note #275 for a PixMap with baseAddr = (NuBus address). Which calls support PixMap 32-bit base addressing with pmVersion = 4?

A As of System 7.0ß1, BitMapToRgn cannot handle a bitmap whose base address is in the NuBus TM address space or any bitmap that requires 32-bit addressing. The problem will be fixed for System 7.0's final release. As far as we know, BitMapToRgn is the only call that doesn't yet support 32-bit addressed bitmaps.

Q Can the LaserWriter 7.x driver be used with System 6.0?

A Yes! LaserWriter 7.x is compatible with both System 7.0 and System 6.0. It's still prerelease software, however. Do not ship the preliminary LaserWriter 7.x driver with your application. You'll be able to ship the final LaserWriter 7 driver with your product as soon as System 7.0 is final. To use the new LaserWriter driver with an AppleShare print spooler, you need a special LaserPrep, available on developer CDs and on AppleLink.

Kudos to our readers who care enough to ask us terrific and well-thought-out questions. The answers to these puzzles have been supplied courtesy of our teams of technical gurus; our thanks to all. Special thanks to Pete "Luke Skywalker" Alexander, Jim "Im" Beninghaus, Rich Collyer, Guillermo Ortiz, Forrest Tanaka, and Scott "Zz" Zimmerman for the material in this Q & A column. *

Have more questions? Need more answers? Take a look at the new developer technical library on AppleLink (updated weekly) or the Q & A stack on the disc that comes withdevelop . *

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

The beginner's guide to Warbits
Warbits is a turn-based strategy that's clearly inspired by Nintendo's Advance Wars series. Since turn-based strategy games can be kind of tricky to dive into, see below for a few tips to help you in the beginning. Positioning is crucial [Read... | Read more »
How to upgrade your character in Spellsp...
So you’ve mastered the basics of Spellspire. By which I mean you’ve realised it’s all about spelling things in a spire. What next? Well you’re going to need to figure out how to toughen up your character. It’s all well and good being able to spell... | Read more »
5 slither.io mash-ups we'd love to...
If there's one thing that slither.io has proved, it's that the addictive gameplay of Agar.io can be transplanted onto basically anything and it will still be good fun. It wouldn't be surprising if we saw other developers jumping on the bandwagon,... | Read more »
How to navigate the terrain in Sky Charm...
Sky Charms is a whimsical match-'em up adventure that uses creative level design to really ramp up the difficulty. [Read more] | Read more »
Victorious Knight (Games)
Victorious Knight 1.3 Device: iOS Universal Category: Games Price: $1.99, Version: 1.3 (iTunes) Description: New challenges awaits you! Experience fresh RPG experience with a unique combat mechanic, packed with high quality 3D... | Read more »
Agent Gumball - Roguelike Spy Game (Gam...
Agent Gumball - Roguelike Spy Game 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Someone’s been spying on Gumball. What the what?! Two can play at that game! GO UNDERCOVERSneak past enemy... | Read more »
Runaway Toad (Games)
Runaway Toad 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: It ain’t easy bein’ green! Tap, hold, and swipe to help Toad hop to safety in this gorgeous new action game from the creators of... | Read more »
PsyCard (Games)
PsyCard 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: From the makers och Card City Nights, Progress To 100 and Ittle Dew PSYCARD is a minesweeper-like game set in a cozy cyberpunk... | Read more »
Sago Mini Robot Party (Education)
Sago Mini Robot Party 1.0 Device: iOS Universal Category: Education Price: $2.99, Version: 1.0 (iTunes) Description: -- Children's Technology Review Editor's Choice -- | Read more »
Egz – The Origin of the Universe (Games...
Egz – The Origin of the Universe 1.0.2 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0.2 (iTunes) Description: ►►► Special offer until 2nd may : get the game at 2.99€ instead of 3.99€ ! ◄◄◄ Egz is a mesmerizing mix... | Read more »

Price Scanner via MacPrices.net

Mac minis on sale for up to $100 off MSRP
B&H Photo has Mac minis on sale for up to $100 off MSRP including free shipping plus NY sales tax only: - 1.4GHz Mac mini: $449 $50 off MSRP - 2.6GHz Mac mini: $649 $50 off MSRP - 2.8GHz Mac mini... Read more
13-inch Retina MacBook Pros on sale for up to...
B&H Photo has 13″ Retina MacBook Pros on sale for $130-$200 off MSRP. Shipping is free, and B&H charges NY tax only: - 13″ 2.7GHz/128GB Retina MacBook Pro: $1169 $130 off MSRP - 13″ 2.7GHz/... Read more
Apple price trackers, updated continuously
Scan our Apple Price Trackers for the latest information on sales, bundles, and availability on systems from Apple’s authorized internet/catalog resellers. We update the trackers continuously: - 15″... Read more
SanDisk Half-Terabyte SSD Optimized for Every...
SanDisk Corporation has announced the SanDisk Z410 SSD, a cost-competitive, half-terabyte solid state drive (SSD) that enables manufacturers to design for a broad range of desktop PCs and laptops.... Read more
Churchill Downs Racetrack Selects VenueNext t...
Churchill Downs Racetrack has announced an agreement with VenueNext to implement its technology platform for the start of Churchill Downs 2016 Spring Meet, which includes the 142nd running of the... Read more
Record 700 Million Pounds of CE Recycled in 2...
The Consumer Technology Association (CTA) reports that a record-setting 700 million pounds of consumer electronics (CE) have been recycled under the eCycling Leadership Initiative (ELI). According to... Read more
Price drops on clearance 12-inch Retina MacBo...
B&H Photo has dropped prices on leftover 2015 12″ Retina MacBooks with models now available starting at $999. Shipping is free, and B&H charges NY tax only: - 12″ 1.1GHz Gray Retina MacBook... Read more
15-inch Retina MacBook Pros available for $20...
B&H Photo has 15″ Retina MacBook Pros on sale for up to $210 off MSRP. Shipping is free, and B&H charges NY tax only: - 15″ 2.2GHz Retina MacBook Pro: $1799 $200 off MSRP - 15″ 2.5GHz Retina... Read more
Target offers Apple Watch Sport for $50 off M...
Target has Apple Watch Sports on sale for $50 off MSRP for a limited time. Choose free shipping or free local store pickup (if available). Sale prices for online orders only, in-store prices may vary... Read more
Apple restocks Certified Refurbished Mac mini...
Apple has restocked Certified Refurbished 2014 Mac minis, with models available starting at $419. Apple’s one-year warranty is included with each mini, and shipping is free: - 1.4GHz Mac mini: $419 $... Read more

Jobs Board

*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Restaurant Manager (Neighborhood Captain) - A...
…in every aspect of daily operation. WHY YOU'LL LIKE IT: You'll be the Big Apple . You'll solve problems. You'll get to show your ability to handle the stress and Read more
Restaurant Manager (Neighborhood Captain) - A...
…in every aspect of daily operation. WHY YOU'LL LIKE IT: You'll be the Big Apple . You'll solve problems. You'll get to show your ability to handle the stress and Read more
Simply Mac *Apple* Specialist- Service Repa...
Simply Mac is the largest premier retailer of Apple products in the nation. In order to support our growing customer base, we are currently looking for a driven Read more
*Apple* Retail - Multiple Positions - Apple,...
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.