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
$102.50
Apple Inc.
+0.25
MSFT
$45.43
Microsoft Corpora
+0.55
GOOG
$571.60
Google Inc.
+2.40

MacTech Search:
Community Search:

Software Updates via MacUpdate

Path Finder 6.5.5 - Powerful, award-winn...
Path Finder is a file browser that combines the familiar Finder interface with the powerful utilities and innovative features. Just a small selection of the Path Finder 6 feature set: Dual pane... Read more
QuarkXPress 10.2.1 - Desktop publishing...
With QuarkXPress, you can communicate in all the ways you need to -- and always look professional -- in print and digital media, all in a single tool. Features include: Easy to Use -- QuarkXPress is... Read more
Skype 6.19.0.450 - Voice-over-internet p...
Skype allows you to talk to friends, family and co-workers across the Internet without the inconvenience of long distance telephone charges. Using peer-to-peer data transmission technology, Skype... Read more
VueScan 9.4.41 - Scanner software with a...
VueScan is a scanning program that works with most high-quality flatbed and film scanners to produce scans that have excellent color fidelity and color balance. VueScan is easy to use, and has... Read more
Cloud 3.0.0 - File sharing from your men...
Cloud is simple file sharing for the Mac. Drag a file from your Mac to the CloudApp icon in the menubar and we take care of the rest. A link to the file will automatically be copied to your clipboard... Read more
LibreOffice 4.3.1.2 - 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
SlingPlayer Plugin 3.3.20.505 - Browser...
SlingPlayer is the screen interface software that works hand-in-hand with the hardware inside the Slingbox to make your TV viewing experience just like that at home. It features an array of... Read more
Get Lyrical 3.8 - Auto-magically adds ly...
Get Lyrical auto-magically add lyrics to songs in iTunes. You can choose either a selection of tracks, or the current track. Or turn on "Active Tagging" to get lyrics for songs as you play them.... Read more
Viber 4.2.2 - Send messages and make cal...
Viber lets you send free messages and make free calls to other Viber users, on any device and network, in any country! Viber syncs your contacts, messages and call history with your mobile device,... Read more
Cocktail 7.6 - General maintenance and o...
Cocktail is a general purpose utility for OS X that lets you clean, repair and optimize your Mac. It is a powerful digital toolset that helps hundreds of thousands of Mac users around the world get... Read more

Latest Forum Discussions

See All

Rhonna Designs Magic (Photography)
Rhonna Designs Magic 1.0 Device: iOS Universal Category: Photography Price: $1.99, Version: 1.0 (iTunes) Description: Want to sprinkle *magic* on your photos? With RD Magic, you can add colors, filters, light leaks, bokeh, edges,... | Read more »
This Week at 148Apps: August 25-29, 2014
Shiny Happy App Reviews   | Read more »
Qube Kingdom – Tips, Tricks, Strategies,...
Qube Kingdom is a tower defense game from DeNA. You rally your troops – magicians, archers, knights, barbarians, and others – and fight against an evil menace looking to dominate your kingdom of tiny squares. Planning a war isn’t easy, so here are a... | Read more »
Qube Kingdom Review
Qube Kingdom Review By Nadia Oxford on August 29th, 2014 Our Rating: :: KIND OF A SQUARE KINGDOMUniversal App - Designed for iPhone and iPad Qube Kingdom has cute visuals, but it’s a pretty basic tower defense game at heart.   | Read more »
Fire in the Hole Review
Fire in the Hole Review By Rob Thomas on August 29th, 2014 Our Rating: :: WALK THE PLANKUniversal App - Designed for iPhone and iPad Seafoam’s Fire in the Hole looks like a bright, 8-bit throwback, but there’s not enough booty to... | Read more »
Alien Creeps TD is Now Available Worldwi...
Alien Creeps TD is Now Available Worldwide Posted by Ellis Spice on August 29th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Dodo Master Review
Dodo Master Review By Jordan Minor on August 29th, 2014 Our Rating: :: NEST EGGiPad Only App - Designed for the iPad Dodo Master is tough but fair, and that’s what makes it a joy to play.   | Read more »
Motorsport Manager Review
Motorsport Manager Review By Lee Hamlet on August 29th, 2014 Our Rating: :: MARVELOUS MANAGEMENTUniversal App - Designed for iPhone and iPad Despite its depth and sense of tactical freedom, Motorsport Manager is one of the most... | Read more »
Motorsport Manager – Beginner Tips, Tric...
The world of Motorsport management can be an unforgiving and merciless one, so to help with some of the stress that comes with running a successful race team, here are a few hints and tips to leave your opponents in the dust. | Read more »
CalPal Update Brings the App to 2.0, Add...
CalPal Update Brings the App to 2.0, Adds Lots of New Stuff Posted by Ellis Spice on August 29th, 2014 [ permalink ] | Read more »

Price Scanner via MacPrices.net

Apple now offering refurbished 21-inch 1.4GHz...
The Apple Store is now offering Apple Certified Refurbished 21″ 1.4GHz iMacs for $929 including free shipping plus Apple’s standard one-year warranty. Their price is $170 off the cost of new models,... Read more
Save $50 on the 2.5GHz Mac mini, on sale for...
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
Save up to $300 on an iMac with Apple refurbi...
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
The Rise of Phablets
Carlisle & Gallagher Consulting Group, a businesses and technology consulting firm focused solely on the financial services industry, has released an infographic depicting the convergence of... Read more
Bad Driver Database App Allows Good Drivers t...
Bad Driver Database 1.4 by Facile Group is a new iOS and Android app that lets users instantly input and see how many times a careless, reckless or just plain stupid driver has been added to the... Read more
Eddy – Cloud Music Player for iPhone/iPad Fre...
Ukraine based CapableBits announces the release of Eddy, its tiny, but smart and powerful cloud music player for iPhone and iPad that allows users to stream or download music directly from cloud... Read more
A&D Medical Launches Its WellnessConnecte...
For consumers and the healthcare providers and loved ones who care for them, A&D Medical, a leader in connected health and biometric measurement devices and services, has launched its... Read more
Anand Lal Shimpi Retires From AnandTech
Anand Lal Shimpi, whose AnandTech Website is famous for its meticulously detailed and thoroughgoing reviews and analysis, is packing it in. Lal Shimpi, who founded the tech site at age 14 in 1997,... Read more
2.5GHz Mac mini, Apple refurbished, in stock...
The Apple Store has Apple Certified Refurbished 2.5GHz Mac minis available for $509, $90 off MSRP. Apple’s one-year warranty is included, and shipping is free. Read more
13-inch 2.5GHz MacBook Pro on sale for $999,...
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

*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
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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.