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).

 
AAPL
$112.94
Apple Inc.
+1.16
MSFT
$47.98
Microsoft Corpora
+0.32
GOOG
$524.87
Google Inc.
+8.52

MacTech Search:
Community Search:

Software Updates via MacUpdate

NeoOffice 2014.6 - Mac-tailored, OpenOff...
NeoOffice is a complete office suite for OS X. With NeoOffice, users can view, edit, and save OpenOffice documents, PDF files, and most Microsoft Word, Excel, and PowerPoint documents. NeoOffice 3.x... Read more
LibreOffice 4.3.5.2 - Free Open Source o...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
CleanApp 5.0.0 Beta 5 - Application dein...
CleanApp is an application deinstaller and archiver.... Your hard drive gets fuller day by day, but do you know why? CleanApp 5 provides you with insights how to reclaim disk space. There are... Read more
Monolingual 1.6.2 - Remove unwanted OS X...
Monolingual is a program for removing unnecesary language resources from OS X, in order to reclaim several hundred megabytes of disk space. It requires a 64-bit capable Intel-based Mac and at least... Read more
NetShade 6.1 - Browse privately using an...
NetShade is an Internet security tool that conceals your IP address on the web. NetShade routes your Web connection through either a public anonymous proxy server, or one of NetShade's own dedicated... Read more
calibre 2.13 - Complete e-library manage...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital librarian... Read more
Mellel 3.3.7 - Powerful word processor w...
Mellel is the leading word processor for OS X and has been widely considered the industry standard since its inception. Mellel focuses on writers and scholars for technical writing and multilingual... Read more
ScreenFlow 5.0.1 - Create screen recordi...
Save 10% with the exclusive MacUpdate coupon code: AFMacUpdate10 Buy now! ScreenFlow is powerful, easy-to-use screencasting software for the Mac. With ScreenFlow you can record the contents of your... Read more
Simon 4.0 - Monitor changes and crashes...
Simon monitors websites and alerts you of crashes and changes. Select pages to monitor, choose your alert options, and customize your settings. Simon does the rest. Keep a watchful eye on your... Read more
BBEdit 11.0.2 - Powerful text and HTML e...
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

Latest Forum Discussions

See All

This Week at 148Apps: December 15-19, 20...
Happy Holidays from 148Apps!   How do you know what apps are worth your time and money? Just look to the review team at 148Apps. We sort through the chaos and find the apps you’re looking for. The ones we love become Editor’s Choice, standing out... | Read more »
New Version of Tempo Smart Calendar Help...
New Version of Tempo Smart Calendar Helps You Plan Your Day Without Opening the App Posted by Jessica Fisher on December 22nd, 2014 [ permalink ] | Read more »
Sparkle - Advanced Cross-Synthesis (Mus...
Sparkle - Advanced Cross-Synthesis 1.0 Device: iOS Universal Category: Music Price: $6.99, Version: 1.0 (iTunes) Description: Sparkle is a tool for advanced spectral hybridizations made of several algorithms that operate on frequency... | Read more »
DICETINY is coming to iOS in 2015
DICETINY is coming to iOS in 2015 Posted by Jessica Fisher on December 22nd, 2014 [ permalink ] Fakedice has announced that they’re bringing their digital board game DICETINY to iOS. | Read more »
It Came From Canada: The Witcher Battle...
The Witcher 3: Wild Hunt may still be a few months away, but very soon players will be able to get a new taste of the acclaimed Polish RPG on their mobile devices with The Witcher Battle Arena. While it trades open-world exploration for compact... | Read more »
The Babies Get Lost Again in the New Azt...
The Babies Get Lost Again in the New Aztec Ruins Update for Light in the Dark Posted by Jessica Fisher on December 22nd, 2014 [ permalink ] | Read more »
Living Room 3D for IKEA Makes All In-App...
Living Room 3D for IKEA Makes All In-App Purchases Free Until 2015 Posted by Jessica Fisher on December 22nd, 2014 [ permalink ] | Read more »
Crossbow Warrior – The Legend of William...
Crossbow Warrior – The Legend of William Tell Review By Lee Hamlet on December 22nd, 2014 Our Rating: :: MISSES THE MARKUniversal App - Designed for iPhone and iPad Crossbow Warrior details the entertaining adventures of legendary... | Read more »
A New Update Races onto Asphalt 8: Airbo...
A New Update Races onto Asphalt 8: Airborne Posted by Jessica Fisher on December 22nd, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Workflow: Powerful Automation Made Simpl...
Workflow: Powerful Automation Made Simple Review By Campbell Bird on December 22nd, 2014 Our Rating: :: GO WITH THE FLOWUniversal App - Designed for iPhone and iPad This powerful app lets users accomplish multiple tasks at touch of... | Read more »

Price Scanner via MacPrices.net

13-inch 2.4GHz Retina MacBook Pro (Apple refu...
The Apple Store has previous-generation Apple Certified Refurbished 13″ 2.4GHz/128GB Retina MacBook Pros available for $999. Apple’s one-year warranty is standard, and shipping is free: - 13″ 2.4GHz/... Read more
Apple resellers offer free overnight shipping
The Apple Store is now offering free next-day shipping on all in stock items if ordered before 12/23/14 at 10:00am PT. Local store pickup is also available within an hour of ordering for any in stock... Read more
Holiday sales continue: MacBook Airs for up t...
 B&H Photo has 2014 MacBook Airs on sale for up to $120 off MSRP, for a limited time, for the Thanksgiving/Christmas Holiday shopping season. Shipping is free, and B&H charges NY sales tax... Read more
Holiday sale continues: 13-inch Retina MacBoo...
 B&H Photo has new 13″ MacBook Pros on sale for up to $150 off MSRP as part of their Holiday pricing. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.5GHz MacBook Pro: $979 save... Read more
Holiday sale continues: 15-inch Retina MacBoo...
 B&H Photo has the new 2014 15″ Retina MacBook Pros on sale for up to $300 off MSRP for a limited time. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $... Read more
Holiday sale: 13-inch 128GB MacBook Air for $...
 Best Buy has the 2014 13-inch 1.4GHz 128GB MacBook Air on sale for $849.99, or $150 off MSRP, on their online store. Choose free home shipping or free local store pickup (if available). Price valid... Read more
13-inch 2.6GHz Retina MacBook Pro on sale for...
Best Buy has lowered their price on the 2014 13″ 2.6GHz/128GB Retina MacBook Pro to $1149.99 on their online store for a limited time. That’s $150 off MSRP and the lowest price available for this... Read more
Kodak Returns to CES With New Consumer Produ...
Former photography colossus Kodak is returning to CES for the first time in three years where the Kodak booth (#21818 South Hall 1) will showcase a wide range of innovative, imaging-related products... Read more
Invaluable Launches New Eponymously -Named A...
Invaluable, the world’s largest online live auction marketplace, hhas announced the official launch of the Invaluable app for iPad, now available for download in the iTunes App Store. Invaluable... Read more
IDC Reveals Worldwide Mobile Enterprise Appli...
International Data Corporation (IDC) last week hosted the IDC FutureScape: Worldwide Mobile Enterprise Applications and Solutions 2015 Predictions Web conference. The session provided organizations... Read more

Jobs Board

*Apple* Store Leader Program (US) - Apple, I...
…Summary Learn and grow as you explore the art of leadership at the Apple Store. You'll master our retail business inside and out through training, hands-on experience, Read more
Project Manager, *Apple* Financial Services...
**Job Summary** Apple Financial Services (AFS) offers consumers, businesses and educational institutions ways to finance Apple purchases. We work with national and 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...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.