TweetFollow Us on Twitter

Sprocket is Here
Volume Number:11
Issue Number:1
Column Tag:Getting Started

Sprocket is Here!

Getting started requires getting in to gear!

By Dave Mark, MacTech Magazine Regular Contributing Author

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

In the last few columns, I told you about a new framework that was going to form the basis for much of the code written for this magazine. Well, as you can see from the title, Sprocket is here! Though Sprocket has existed in various incarnations for a while, I’ve only recently had the chance to really get into it. (I’ve been completely consumed with the goal of getting Ultimate Mac Programming out the door in time for January MacWorld).

This month, we’ll take a walk through the Sprocket architecture, focusing on the files and routines you’ll work with as you customize Sprocket to fit your needs.

Getting Sprocket

The first thing you’ll need to do is get a copy of the latest version of Sprocket. It’s included on the monthly MacTech source code disks and is archived at the usual online sites (which are listed every month on page 2).

Hopefully, by the time you read this, there will be versions of Sprocket for both Symantec C++ and Metrowerks CodeWarrior. As I write this, I’ve only got the CodeWarrior version, so bear with this unintended bias. Hopefully, there won’t be too many differences between the two versions.

As you get into Sprocket, it’s important to realize that we are at the beginning of a long evolutionary process. Sprocket was just born and there will no doubt be lots of design changes, bugs, and what have you. Here’s your chance to get in on the ground floor. If you find a bug, or have any specific comments about or feature requests for Sprocket, send a complete description to sprocket@hax.com.

The Sprocket Files

Open the Sprocket folder and launch the Sprocket project (mine was called SprocketSample.µ). You’ll notice that the files are organized into three different groups.

On the 680x0 side of the fence, each of these groups takes the form of a segment. On the PowerPC side, segments are a thing of the past, so the file groupings are more for aesthetics.

The first group of files is called Sprocket Code (see Figure 1), and is made up of the files that are private to Sprocket. These are the files that implement things like the event loop, the main base classes, the required Apple events, etc. For now, just ignore these files. As you get to know Sprocket and have a few Sprocket applications under your belt, you might want to explore these files and possibly tweak a few things to fit your specific needs.

The second group of files is labeled GX Graphics Libraries and contains routines you’ll need to work with Quickdraw GX. By the time you read this, the file(s) in this section may have been rolled in with the rest of the files in the Sprocket Code section.

The third group of files is labeled Application Specific. This is where you’ll put your code. As you’ll see, contained within the files in this section are a series of 9 routines that you must provide to make Sprocket run. These routines do things like perform application initialization, dispatch menu selections, and create new documents. Every Sprocket application has these routines, including the generic Sprocket application that came with Sprocket in the first place. Each time you create a new Sprocket application, you’ll duplicate the folder containing the application specific files, then edit the routines in those files as you see fit. At the very least, you’ll need to make sure that the 9 critical routines do what you need them to.

Figure 1. My Sprocket project file, as implemented by CodeWarrior.

A Quick Sprocket Test Drive

Before we get to them, let’s take Sprocket for a quick spin, just to get a feel for what it looks like. Once again, keep in mind the fact that I’m writing this in November and that things will undoubtedly change by the time you read this.

When you launch the generic Sprocket application, two new windows appear. The window on the left is a palette or tool window (Figure 2). It floats, meaning that it always appears in front of all other windows. Imagine this window filled with tool icons. When the user clicks on an icon, you’ll change the cursor to reflect the new tool and implement the tool’s behavior as the user clicks and drags in a document window.

Figure 2. The generic Sprocket tool window.

The other window that appears (Figure 3) is a document window, customized to include a nifty pair of spinning arrows in their own pane, a pair of horizontal lines that separate this pane from the main content region, and a pair of scroll bars. If you select New from the File menu, a new, untitled document window will appear. When you create your own sprocket applications, you’ll have complete control over the look and behavior of your document windows. Customizing the window (as Dave did with his spinning arrows) is up to you. Sprocket handles generic window behavior like clicks in a window’s close, grow, or zoom area. When drawing is necessary, Sprocket will call the window’s Draw() method, which you’ll override with your own Draw routine. You’ll see how to do that in next month’s column.

Figure 3. A generic Sprocket document window with the spinning cursors.

If you select Preferences... from the File menu, the preferences dialog in Figure 4 will appear. This will eventually evolve into a scrolling list of icons, each of which gives the user access to a different portion of the application preferences. Got any ideas for this dialog? Send ‘em in!

The Sprocket menu bar is pretty generic (appropriately so). It features standard File and Edit menus, as well as a not-so-standard Debug menu. If your Mac is AOCE aware (if you have PowerTalk installed, for example), the Debug menu will feature an an item that lets you create a new window with an AOCE mailer attached to it.

If you want to explore this topic further (we won’t get into it for a while) search for the flag qAOCEAware. If you won’t be supporting AOCE, you’ll want to turn this flag off, since it will save you considerably in code size.

Figure 4. The Sprocket generic preferences dialog as it appeared in November.

Let’s take a look at two of the files in the Application Specific group. The first of these files, AppSpecific.rsrc, holds the resources you want to add to Sprocket. The second file, App.cp, holds the nine routines that you’ll need to provide to customize Sprocket. We’ll get to the rest of the Application Specific files in next month’s column.

AppSpecific.rsrc

Sprocket divides its resources between two resource files. Sprocket.rsrc contains the resources that are private to Sprocket, while AppSpecific.rsrc contains the resources you’ll add to the project yourself. Take some time to look through the resources that come with the generic Sprocket project. As you look through AppSpecific.rsrc, you’ll notice that there are MENU resources for the Apple and Debug menus, but that there are no MENUs for the File and Edit menus. The File and Edit menus are defined in Sprocket.rsrc. Notice that the Debug menu is not included in the MBAR resource used by Sprocket (MBAR 128). The Debug menu was added by Sprocket using a call to InsertMenu() (Look in App.cp for the constant mDebug to follow this process). Take all this with a grain of salt, since it will most likely change in the near future. By the time you read this, a new version of Sprocket that gives you complete control over the menu bar will be released. The plan is that you will provide an MBAR resource and MENU resources to go along with the MENU ids listed in the MBAR resource. At this point, it’s not clear how the File and Edit menus will be handled. More on this as Sprocket evolves.

App.cp

This is the most important of your source code files. Here’s where the aforementioned 9 mandatory routines reside. As you get started, you’ll want to edit a copy of App.cp, using the existing 9 routines as the basis for your own code. Here’s the function prototypes for these 9 routines which you must supply (the prototypes are at the very bottom of <Sprocket.h>):

// initialization & tear down
extern  OSErr  SetupApplication(void);
extern  voidTearDownApplication(void);

// menu handling:
extern  voidHandleMenu(TWindow * topWindowObj,long menuCode);

// scrap coercion hooks:
extern  voidWriteLocalClipboardToScrap(void);
extern  voidReadLocalClipboardFromScrap(void);

// document handling routines:
extern  OSErr  CreateNewDocument(void);
extern  OSErr  OpenDocument(LetterDescriptor *,void *);
extern  OSErr  PrintDocument(LetterDescriptor *,void *);
extern  Boolean  QuitApplication(void);

SetupApplication() is where you’ll do your application specific initialization. You’ll have to learn what Sprocket does and doesn’t do for you. For example, Sprocket doesn’t set up QuickTime and it only installs handlers for the four required Apple events.

In TearDownApplication(), your documents have already been closed and you know that your application is going down. Here’s a chance to write out your preferences file, shut down any network connections, etc.

HandleMenu() is your menu selection dispatch routine. The first parameter is a pointer to an object that represents the active window at the time the selection was made. The second parameter is a standard four byte menu/item combination you can take apart with HiWord() and LoWord(). You can dispatch menu selections using C or C++, whichever works for you. That’s one of the nice things about Sprocket. Though it is definitely C++ based, it doesn’t force you to work in C++. The generic Sprocket application does all its menu item processing inside the HandleMenu() routine, but you’ll probably want to shift the processing into a separate file.

The routines ReadLocalClipboardFromScrap() and WriteLocalClipboardToScrap() load the scrap into the local clipboard and write the local clipboard back out to the scrap. You’ll fill these routines in when you’re ready to support the Cut, Copy, and Paste Edit menu items.

CreateNewDocument() gets called by the oapp Apple event handler. No matter what horrid error you encounter, do not exit the program inside this routine or you will completely hose the Apple Event Manager. Use this routine to create a new document object. If you encounter an error, return the error code, otherwise return noErr.

OpenDocument() gets called by the odoc Apple Event handler for each document used to launch the application. A recordable application will also create and send an odoc event to itself when the user selects Open... from the File menu. At this point, Sprocket is not recordable (sounds like an idea for a future column). OpenDocument() should use the information in the LetterDescriptor parameter to open a file and use the information in the file to create a new document object. A LetterDescriptor is a union, holding either an FSSpec or an AOCE letter spec. The union starts with a boolean that indicates which type it is. Again, be sure you don’t exit directly from this routine. If you encounter an error, return the error code, otherwise return noErr.

PrintDocument() will get called in response to a pdoc Apple event. Sprocket doesn’t have printing support yet, so leave this routine until printing is there.

QuitApplication() gets called in response to a quit Apple event. QuitApplication() should close every open document. You might want to maintain a list of open document objects, then have QuitApplication() step through the list, calling each document’s Close() member function (also known as the document’s Close() method). If a document has been changed since it was opened, the Close() method should put up the standard “Save changes” alert, giving the user the chance to cancel the quit. If the user cancels the quit, QuitApplication() should return false. If all the documents close successfully, QuitApplication() should return true, and Sprocket will call TearDownApplication().

Till Next Month

In next month’s column, we’ll take a look at the files that define the window objects used by Sprocket. We’ll customize Sprocket by overriding some of the different window Draw() methods. Between now and then, take some time to read through the files App.cp, DocWindow.cp, ToolWindow.cp, PreferencesDialogWIndow.cp, and MailableDocWindow.cp. Experiment. Open up the “.h” file associated with each of these files and check out the class definition that forms the basis for each file. You’ll see that each of these window classes is derived from Sprocket’s TWindow class. Check out the DocWindow class. Notice that it overrides the TWindow Draw() method. If you want to affect what gets drawn in a DocWindow, you’ll want to edit the DocWindow Draw() method. Try it! Just be sure to make a copy of the Sprocket project file and AppSpecific folder so you’ll maintain your original copy of Sprocket (just in case).

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

GraphicConverter 10.5.1 - $39.95
GraphicConverter is an all-purpose image-editing program that can import 200 different graphic-based formats, edit the image, and export it to any of 80 available file formats. The high-end editing... Read more
Delicious Library 3.7 - Import, browse a...
Delicious Library allows you to import, browse, and share all your books, movies, music, and video games with Delicious Library. Run your very own library from your home or office using our... Read more
Adobe Animate CC 2017 18.0.0.107 - Anima...
Animate CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Flash Professional customer). Animate CC 2018 (was Flash CC) lets you... Read more
Adobe After Effects CC 2018 15.0 - Creat...
After Effects CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous After Effects customer). The new, more connected After Effects CC... Read more
Adobe Premiere Pro CC 2018 12.0.0 - Digi...
Premiere Pro CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Premiere Pro customer). Adobe Premiere Pro CC 2018 lets you edit... Read more
Alarm Clock Pro 10.3 - $19.95
Alarm Clock Pro isn't just an ordinary alarm clock. Use it to wake you up in the morning, send and compose e-mails, remind you of appointments, randomize the iTunes selection, control an internet... Read more
Adobe Lightroom 20170919-1412-ccb76bd] -...
Adobe Lightroom is available as part of Adobe Creative Cloud for as little as $9.99/month bundled with Photoshop CC as part of the photography package. Lightroom 6 is also available for purchase as a... Read more
Adobe Illustrator CC 2018 22.0.0 - Profe...
Illustrator CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Illustrator customer). Adobe Illustrator CC 2018 is the industry... Read more
Hopper Disassembler 4.3.0- - Binary disa...
Hopper Disassembler is a binary disassembler, decompiler, and debugger for 32- and 64-bit executables. It will let you disassemble any binary you want, and provide you all the information about its... Read more
Adobe InDesign CC 2018 13.0.0.125 - Prof...
InDesign CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous InDesign customer). Adobe InDesign CC 2018 is part of Creative Cloud.... Read more

ICEY (Games)
ICEY 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: ICEY is a 2D side-scrolling action game. As you follow the narrator's omnipresent voice, you will see through ICEY's eyes and learn the... | Read more »
The best new games we played this week -...
We've made it, folks. Another weekend is upon us. It's time to sit back and relax with the best new releases of the week. Puzzles, strategy RPGs, and arcade games abound this week. There's a lot of quality stuff to unpack this week, so let's hop... | Read more »
Wheels of Aurelia (Games)
Wheels of Aurelia 1.0.1 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0.1 (iTunes) Description: | Read more »
Halcyon 6: Starbase Commander guide - ti...
Halcyon 6 is a well-loved indie RPG with stellar tactical combat and some pretty good writing, too. It's now landed on the App Store, so mobile fans, if you're itching for a good intergalactic adventure, here's your game. Being a strategy RPG, the... | Read more »
Game of Thrones: Conquest guide - how to...
Fans of base building games might be excited to know that yet another entry in the genre has materialized - Game of Thrones: Conquest. Yes, you can now join the many kingdoms of the famed book series, or create your own, as you try to conquer... | Read more »
Halcyon 6: Starbase Commander (Games)
Halcyon 6: Starbase Commander 1.4.2.0 Device: iOS Universal Category: Games Price: $6.99, Version: 1.4.2.0 (iTunes) Description: An epic space strategy RPG with base building, deep tactical combat, crew management, alien diplomacy,... | Read more »
Legacy of Discord celebrates its 1 year...
It’s been a thrilling first year for fans of Legacy of Discord, the stunning PvP dungeon-crawling ARPG from YOOZOO Games, and now it’s time to celebrate the game’s first anniversary. The developers are amping up the festivities with some exciting... | Read more »
3 reasons to play Thunder Armada - the n...
The bygone days of the Battleship board game might have past, but naval combat simulators still find an audience on mobile. Thunder Armada is Chinese developer Chyogames latest entry into the genre, drawing inspiration from the explosive exchanges... | Read more »
Experience a full 3D fantasy MMORPG, as...
Those hoping to sink their teeth into a meaty hack and slash RPG that encourages you to fight with others might want to check out EZFun’s new Eternity Guardians. Available to download for iOS and Android, Eternity Guardians is an MMORPG that lets... | Read more »
Warhammer Quest 2 (Games)
Warhammer Quest 2 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Dungeon adventures in the Warhammer World are back! | Read more »

Price Scanner via MacPrices.net

9″ iPads on sale for $30 off, starting at $29...
MacMall has 9″ iPads on sale for $30 off including free shipping: – 9″ 32GB iPad: $299 – 9″ 128GB iPad: $399 Read more
Apple restocks full line of refurbished 13″ M...
Apple has restocked a full line of Apple Certified Refurbished 2017 13″ MacBook Pros for $200-$300 off MSRP. A standard Apple one-year warranty is included with each MacBook, and shipping is free.... Read more
13″ 3.1GHz/256GB MacBook Pro on sale for $167...
Amazon has the 2017 13″ 3.1GHz/256GB Space Gray MacBook Pro on sale today for $121 off MSRP including free shipping: – 13″ 3.1GHz/256GB Space Gray MacBook Pro (MPXV2LL/A): $1678 $121 off MSRP Keep an... Read more
13″ MacBook Pros on sale for up to $120 off M...
B&H Photo has 2017 13″ MacBook Pros in stock today and on sale for up to $120 off MSRP, each including free shipping plus NY & NJ sales tax only: – 13-inch 2.3GHz/128GB Space Gray MacBook... Read more
15″ MacBook Pros on sale for up to $200 off M...
B&H Photo has 15″ MacBook Pros on sale for up to $200 off MSRP. Shipping is free, and B&H charges sales tax in NY & NJ only: – 15″ 2.8GHz MacBook Pro Space Gray (MPTR2LL/A): $2249, $150... Read more
Roundup of Apple Certified Refurbished iMacs,...
Apple has a full line of Certified Refurbished 2017 21″ and 27″ iMacs available starting at $1019 and ranging up to $350 off original MSRP. Apple’s one-year warranty is standard, and shipping is free... Read more
Sale! 27″ 3.8GHz 5K iMac for $2098, save $201...
Amazon has the 27″ 3.8GHz 5K iMac (MNED2LL/A) on sale today for $2098 including free shipping. Their price is $201 off MSRP, and it’s the lowest price available for this model (Apple’s $1949... Read more
Sale! 10″ Apple WiFi iPad Pros for up to $100...
B&H Photo has 10.5″ WiFi iPad Pros in stock today and on sale for $50-$100 off MSRP. Each iPad includes free shipping, and B&H charges sales tax in NY & NJ only: – 10.5″ 64GB iPad Pro: $... Read more
Apple iMacs on sale for up to $130 off MSRP w...
B&H Photo has 21-inch and 27-inch iMacs in stock and on sale for up to $130 off MSRP including free shipping. B&H charges sales tax in NY & NJ only: – 27″ 3.8GHz iMac (MNED2LL/A): $2179 $... Read more
2017 3.5GHz 6-Core Mac Pro on sale for $2799,...
B&H Photo has the 2017 3.5GHz 6-Core Mac Pro (MD878LL/A) on sale today for $2799 including free shipping plus NY & NJ sales tax only . Their price is $200 off MSRP. 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
Commerce Engineer, *Apple* Media Products -...
Commerce Engineer, Apple Media Products (New York City) Job Number: 113028813New York City, New York, United StatesPosted: Sep. 20, 2017Weekly Hours: 40.00 Job Read more
US- *Apple* Store Leader Program - Apple (Un...
US- Apple Store Leader Program Job Number: VariousUnited StatesPosted: Oct. 19, 2017Retail Store Job Summary Learn and grow as you explore the art of leadership at Read more
Product Manager - *Apple* Pay on the *Appl...
Job Summary Apple is looking for a talented product manager to drive the expansion of Apple Pay on the Apple Online Store. This position includes a unique Read more
*Apple* Retail - Multiple Positions - Farmin...
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.