TweetFollow Us on Twitter

Menus, Windows
Volume Number:2
Issue Number:8
Column Tag:ABC's of C

Menus and Windows in LightSpeed C

By Bob Gordon, Apropos Publications, Contributing Editor

An easy to follow user interface is one component of good quality software. On the Macintosh, the design of the user interface is largely laid out for us. Use windows and menus. Last month, we used control keys to place a single window on the screen and make some modifications to it. This month we will do the same thing but use menus rather than control keys. You will notice that this month's program is very similar to last month's. There are some obvious differences from the addition of menus and some less obvious differences because I used a different compiler. Since the program contains functions from last month, we'll tie up a few loose ends, and cover a basic C concept as well.

C Assignment Statements

The assignment statement is probably the most basic statement in most languages. I don't think I've used it yet in any of these programs because we have done very little arithmetic. Since it is so basic, we'll go over it this month.

The C assignment operator is the equal sign:

 x = 7;
 y = a + b;
 z = max(x,y);

The effect of the assignment operator is to take the value of the right hand side and place in the variable on the left hand side.

With most languages, this would be about as much as we would say. C, however, also offers a set of specialized assignment operators. These apply when the variable on the left is also on the right as in:

 x = x + 1; /* increment x  by 1 */

The preferred C form is:

 x += 1;/* increment x by 1 */

This is a bit easier to follow as it is obvious that what we want to do is increment x. It would also be obvious to the compiler, which may generate more efficient code.

Here is a list of all the C assignment operators.

= assignment

+= addition assignment

-= subtraction assignment

*= multiplication assignment

/= division assignment

%= modulus assignment

>>= shift right assignment

<<= shift left assignment

&= bitwise AND assignment

|= bitwise inclusive OR

^= bitwise exclusive OR

The first three are the most frequently used, but you may run across another. Don't be too surprised when you see one.

Cleaning Up the Windows

There is one point from last months program about windows that deserve some clarification: The use of the "cast" in the call to NewWindow(). Each parameter of a function has to receive the correct type. C does not do type checking on external functions, and passing the wrong type can yield disastrous results. NewWindow() expects a WindowPtr for its behind parameter (specifies an existing window to place the new window behind). If the new window should be in front of all the other windows behind receives a minus one, but the minus one must be a window pointer.

To change the type of an object a cast is used. Place the type name in parentheses before the object you wish to change. The effect is as if there were a new variable of the proper type to which you assigned the orignal object. The original object is unchanged. It is preferrable to use a cast rather than an integer or long because the internal representation of an integer or long may not be the same as that of a pointer. So, to change minus one to a WindowPtr, do:

(WindowPtr)-1

This will ensure that the parameter is not only of the same size, but of the correct type as well.

LightspeedC

Since this column is devoted to learning to program in C on the Macintosh, I have been on the lookout for tools that will facilitate the learning process. LightspeedC is such a tool. Its major advantages from our point of view is that it is very fast at compiling and linking and that it places you at the correct position in your source file if the compiler detects an error. The result is that you can edit, compile, link, and run your program very rapidly, make small variations in the code and determine their effect, and generally have the opportunity to make more mistakes in a shorter period of time. If we learn from our mistakes, Lightspeed C is a useful tool for learning C on the Macintosh.

LightspeedC is different from the other available C compilers as it does not use a Unix-like setting [Yea! -Ed.] -nor does it use separate programs in the Macintosh window environment. Instead it creates its own enviornment (that follows the Macintosh User Interface) from which all editing, compiling, linking, and running take place. The integrated editor is roughly similar to the Edit application. Menus available from inside the editor allow you to run, compile, or just check the syntax. As soon as the compiler detects an error, you are returned to the editor with the cursor at the location the compiler found the error. In other words, you get one error at a time.

The link operation is extremely fast. With this month's small program, I often did not notice the link had happened. If you choose the run option from the editor, it will compile, link, and launch your program. When you quit your program, the LightspeedC environment reloads, and you can continue.

The key to the speed seems to be the system's use of a project. The necessary files are installed into the project, and I guess much of the linking takes place at intallation or compile time. The project also provides a make facility-it keeps track of changes in source, include, and library files, and recompiles them as necessary.

I came across a few problems in using LightspeedC. First, it follows the proposed ANSI standard for passing structures as parameters. As I mentioned last month, C traditionally only allowed passing pointers to structures and this complicates the passing of the Macintosh Point type (which is a four byte structure that the Mac expects to find passed by value rather than by reference). LightspeedC passes a Point correctly by value. This is not a problem except it took me over an hour to realize what was going on. I wrote the menu program under Mac C first, and then installed the source in Lightspeed.

A second problem is that Lightspeed does not include the QD variable we used last month to obtain the size of the screen. You will note in this month's program that the dragbound rectangle (which describes the limits for dragging a window) and the limit rectangle (which set the maximum size to which a window may grow) are set with hard coded numbers.

A more serious problem is that there is no way to easily print to the screen in the Macintosh environment. (LightspeedC includes printf() as well as a number of other Unix-type output functions, but the use of any of these invokes a Unix environment that eliminates the menu bar and windows. Since I was trying to debug a problem with windows, this was not at all useful. By the way, LightspeedC includes one of the larger collection of Unix compatible functions in its libraries.) Not having a printf() like routine for the Mac environment considerably reduces the usefulness of LightspeedC as a learning tool. [Too bad. They could use an assembler too! -Ed.]

The manual that comes with the package is a large format paperback. About a third of its pages are devoted to a description of all the Unix compatible functions. (Many of these, such as the string functions, are useful in the Macintosh environment. Whether such things as the memory management and file handling routines are useful would depend on whether they invoke the Unix environment and whether you wish to port your program off the Macintosh.) The descriptions of the Macintosh functions are limited to listing the name and calling sequence in the order they appear in Inside Macintosh. Alphabetical order would have been better. [Why is it developers keep slighting the Mac toolbox in their documentation? -Ed.]

Finally, Lightspeed uses different names for its header files There is no standard so this is not a problem. Since I moved the code to Lightspeed from Mac C, it would not compile immediately. I decided to change the names of the header files so they would look familiar to most people.

In general I am very impressed with the package as a learning environment. The fact that it generates fast, compact code (a fact I have not verified) is simply a bonus.

C What's on the Menu

This program does the same thing last month's program did except it's control is through menus. There is one additional visible (to the user) feature: an item in the File menu will add a new menu called Test. The Test menu allows items to be checked. The comments in the code describe other differences. I'll describe each function briefly.

main()

Main has basically disappeared. It simply calls two initialization functions. I prefer to keep the system initialization separate from the application. Eventually we'll have everything we need in the system application and will not have to change it.

initsys()

Initializes system stuff. If you compare the initialization this month with last month's, you will notice the first two lines were not in last time. They are handled automatically by Mac C.

initapp()

Sets up the menus. AppendMenu() adds the menu string(s) to the menu; InserMenu() adds the menu to the menu bar. Notice the string in the calls to AppendMenu(). It contains several metacharacters as Inside Macintosh calls them. They control the display and sometimes the operation of the menu items.

Meta Characters Explained

Character Meaning

; Separates items (can also use return)

^ Item has an icon; followed by icon number

! Item is marked with following character

< Item is in special style, followed by B, I, U, O, or S

/ Item has keyboard equivalent, followed by the character

( Item is disabled

eventloop()

An event loop like we have seen before. The test on theWindow at the begining enables/disables the items in the File menu to open/close the window. The disabled items are in gray. We probably should disable the Apple menu because we don't support Desk Accessories. Other items in other menus should switch as well. You might try to add these features.

Notice the special handling of keyDown events. In case of keyDown, the modifers field is checked for the command key being down. If the command key is down, MenuKey() is used to generate the same code as MenuSelect(), and the code is passed to domenu(). This is how command keys work with menus. You might want to add some more command keys to the menus.

domouse()

This is almost identical to last month's. The only difference is that here we call domenu() if the mouse is in the menu bar. Remember to handle er->where correctly for your compiler.

domenu()

This is simply a switch. The menu code consists of two components packed into a long. HiWord() and LoWord() are two Toolbox functions that extract the lower and upper words of a long.

dofile()

Contains the code to handle the File menu. Note cases five and six. They contain a call to DrawMenuBar() because they change the menu bar. Any changes do not appear until the menu bar is redrawn.

dowind()

Handles the Window menu. Add DisableItem() and EnableItem() calls to this one.

dotest()

This does not do anything except mark and unmark the items.

The Program

/* menu and window manager demonstration 
 * base on program in 
 * Using Macintosh Toolbox with C
 * page 91
 *
 * Compiled with LightspeedC
 *
 * Important note for Mac C users:
 * Everyplace you see event->where,
 * replace it with &event->where
 */
 
 
 #include "abc.h"/* our own header, see last month */
 #include "Events.h"
 #include "Window.h"
 #include "Menu.h"
 
 /* defines for menu ID's */
 
 #defineMdesk    100
 #defineMfile    101
 #defineMedit    102
 #defineMwind    103
 #defineMtest    104
 
 /* Global variables */
 
 MenuHandle menuDesk;/* menu handles */
 MenuHandle menuFile;
 MenuHandle menuEdit;
 MenuHandle menuWind;
 MenuHandle menuTest;
 
 
 WindowPtrtheWindow;
 WindowRecord  windowRec;
 Rect   dragbound;
 Rect   limitRect;
 
main()
{
 initsys(); /* system initialization */
 initapp(); /* application initialization */
 eventloop();  /* Do it! */
}


/* system initialization 
 * note use of hard coded screen sizes
 * with LightspeedC.  This will work
 * with other compilers but is not
 * good practice
 */
initsys() 
{
 InitGraf(&thePort); /* these two lines done */
 InitFonts();    /* automatically by Mac C */
 InitWindows();
 InitCursor();
 InitMenus();
 theWindow = Nil;/*indicates no window */
 SetRect(&dragbound,0,0,512,342);
 SetRect(&limitRect,60,40,508,318);
}


/*
 * application initialization
 * Sets up menus.
 * Each menu is a separate group
 * of lines.  Note the last menu
 * is appended but not inserted.  This
 * makes it part of the menu list but 
 * not in the menu bar.
 */
initapp()
{
 menuDesk = NewMenu(Mdesk,CtoPstr("\24"));
 AddResMenu (menuDesk, 'DRVR');
 InsertMenu (menuDesk, 0);
 
 menuFile = NewMenu(Mfile, CtoPstr("File"));
 AppendMenu (menuFile, 
 CtoPstr("Open Window/M;Close Window/X;Quit/Q"));
 AppendMenu (menuFile, 
 CtoPstr("(-;Show Test;(Hide Test"));
 InsertMenu (menuFile, 0);
 
 menuEdit = NewMenu(Medit, CtoPstr("Edit"));
 AppendMenu (menuEdit, 
 CtoPstr("Undo;(-;Cut;Copy;Paste;Clear"));
 InsertMenu (menuEdit, 0);
 
 menuWind = NewMenu(Mwind, CtoPstr("Window"));
 AppendMenu (menuWind, 
 CtoPstr("Hide;Show;New Title"));
 InsertMenu (menuWind, 0);
 
 menuTest = NewMenu(Mtest, CtoPstr("Test"));
 AppendMenu (menuTest, 
 CtoPstr("Pick;One;Of;These"));
 
 DrawMenuBar();
}
 
 
/* Event Loop 
 * Loop forever until Quit
 */
eventloop()
{
 EventRecordtheEvent;
 char   c;
 short  windowcode;
 WindowPtrww;
 
 while(True)
 {
 if (theWindow)      /* this code is here to */
 { /* prevent closing an */
 EnableItem(menuFile,2);  /* a closed window */
 DisableItem(menuFile,1);
 }
 else   
 { 
 EnableItem(menuFile,1);
 DisableItem(menuFile,2);
 }
 
 if (GetNextEvent(everyEvent,&theEvent))
 switch(theEvent.what)    
 
 { /* only check key and */
 case keyDown:   /* mouse down events */
 if (theEvent.modifiers & cmdKey)
 {
 c = theEvent.message & charCodeMask;
 domenu(MenuKey(c));
 }
 break;
 case mouseDown:
 domouse(&theEvent);
 break;
 default:
 break;
 }
 }
}


/* domouse
 * handle mouse down events
 */
domouse(er)
 EventRecord*er;
{
 short  windowcode;
 WindowPtrwhichWindow;
 short  ingo;
 long   size;
 
 windowcode = FindWindow(er->where, 
 &whichWindow);
 switch (windowcode)
 {
 case inDesk:
 if (theWindow notequal 0)
 {
 HiliteWindow(theWindow, False);
 DrawGrowIcon(theWindow);
 }
 break;
 case inMenuBar:
 domenu(MenuSelect(er->where));
 break;
 case inSysWindow:
 SysBeep(1);
 break;
 case inContent:
 HiliteWindow(whichWindow,True);
 DrawGrowIcon(theWindow);
 break;
 case inDrag:
 DragWindow(whichWindow, 
   er->where, &dragbound);
 DrawGrowIcon(theWindow);
 break;
 case inGrow:
 /* not included this month */
 break;
 case inGoAway:
 ingo = TrackGoAway(whichWindow,er->where);
 if (ingo)
 {
 CloseWindow(whichWindow);
 theWindow = Nil;
 }
 break;
 }
}

/* domenu
 * handles menu activity
 * simply a dispatcher for each
 * menu.
 */
domenu(mc)
 long   mc; /* menu result */
{
 short  menuId;
 short  menuitem;
 
 menuId = HiWord(mc);
 menuitem = LoWord(mc);
 
 switch (menuId)
 {
 case Mdesk : break;
 /* not handling DA's */
 case Mfile : dofile(menuitem);
  break;
 case Medit : break;
 
 case Mwind : dowind(menuitem);
  break;
 case Mtest : dotest(menuitem);
  break;
 }
 HiliteMenu(0);
}

/* dofile
 * handles file menu
 */
dofile(item)
 short  item;
{
 char   *title1; /* first title for window */
 Rect   boundsRect;
 
switch (item)
 {
 case 1 : /* open the window */
 title1 = "ABC Window";
 SetRect(&boundsRect,50,50,300,150);
 theWindow = NewWindow(&windowRec, 
 &boundsRect,CtoPstr(title1),True,
 documentProc,(WindowPtr) -1, True, 0);
 DrawGrowIcon(theWindow);
 PtoCstr(title1);
 DisableItem(menuFile,1);
 EnableItem(menuFile,2);
 break;
 
 case 2 : /* close the window */
 CloseWindow(theWindow);
 theWindow = Nil;
 DisableItem(menuFile,2);
 EnableItem(menuFile,1);
 break;
 
 case 3 : /* Quit */
 ExitToShell();
 break;
 
 case 5 : /* Install additional menu */
 InsertMenu(menuTest,0);
 EnableItem(menuFile,6);
 DisableItem(menuFile,5);
 DrawMenuBar();
 break;
 
 case 6 : /* remove additional menu */
 DeleteMenu(Mtest);
 EnableItem(menuFile,5);
 DisableItem(menuFile,6);
 DrawMenuBar();
 break;
 
 }
}

/*
 * dowind
 * handles window menu 
 * Note that each case contains an
 * if testing the existance of the
 * window.  This could be written
 * with one if before the switch.
 */
dowind(item)
 short  item;
{
 char   *title2; /* second title for window */
 
 switch (item)
 {
 case 1 : /* Hide */
 if (theWindow)
 HideWindow(theWindow);
 break;
 case 2 : /* Show */
 if (theWindow)
 ShowWindow(theWindow);
 break;
 case 3 : /* Change title */
 if (theWindow)
 {
 title2 = "A Different Title";
 SetWTitle(theWindow, CtoPstr(title2));
 PtoCstr(title2);
 }
 break;
 }
}

/* dotest
 * Handles new menu.
 * All this does is mark menu
 * items if they are not marked and
 * unmark them if they are.
 */
dotest(item)
 short  item;
{
 short  mark;
 
 GetItemMark(menuTest,item,&mark);
 if (mark)
 CheckItem(menuTest,item,False);
 else
 CheckItem(menuTest,item,True);
}  
 
AAPL
$105.01
Apple Inc.
+0.18
MSFT
$45.45
Microsoft Corpora
+0.43
GOOG
$539.20
Google Inc.
-4.79

MacTech Search:
Community Search:

Software Updates via MacUpdate

BusyCal 2.6.3 - Powerful calendar app wi...
BusyCal is an award-winning desktop calendar that combines personal productivity features for individuals with powerful calendar sharing capabilities for families and workgroups. BusyCal's unique... Read more
calibre 2.7 - Complete e-library managem...
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... Read more
Skitch 2.7.3 - Take screenshots, annotat...
With Skitch, taking, annotating, and sharing screenshots or images is as fun as it is simple.Communicate and collaborate with images using Skitch and its intuitive, engaging drawing and annotating... Read more
Delicious Library 3.3.2 - Import, browse...
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
Art Text 2.4.8 - Create high quality hea...
Art Text is an OS X application for creating high quality textual graphics, headings, logos, icons, Web site elements, and buttons. Thanks to multi-layer support, creating complex graphics is no... Read more
Live Interior 3D Pro 2.9.6 - Powerful an...
Live Interior 3D Pro is a powerful yet very intuitive interior designing application. View Video Tutorials It has every feature of Live Interior 3D Standard, plus some exclusive ones: Create multi... Read more
The Hit List 1.1.7 - Advanced reminder a...
The Hit List manages the daily chaos of your modern life. It's easy to learn - it's as easy as making lists. And it's powerful enough to let you plan, then forget, then act when the time is right.... Read more
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

Latest Forum Discussions

See All

nPlayer looks to be the ultimate choice...
Developed by Newin Inc, nPlayer may seem like your standard video player – but is aiming to be the best in its field by providing high quality video play performance and support for a huge number of video formats and codecs. User reviews include... | Read more »
Fighting Fantasy: Caverns of the Snow Wi...
Fighting Fantasy: Caverns of the Snow Witch Review By Jennifer Allen on October 24th, 2014 Our Rating: :: CLASSY STORYTELLINGUniversal App - Designed for iPhone and iPad Fighting Fantasy: Caverns of the Snow Witch is a sterling... | Read more »
A Few Days Left (Games)
A Few Days Left 1.01 Device: iOS Universal Category: Games Price: $3.99, Version: 1.01 (iTunes) Description: Screenshots are in compliance to App Store's 4+ age rating! Please see App Preview for real game play! **Important: Make... | Read more »
Toca Boo (Education)
Toca Boo 1.0.2 Device: iOS Universal Category: Education Price: $2.99, Version: 1.0.2 (iTunes) Description: BOO! Did I scare you!? My name is Bonnie and my family loves to spook! Do you want to scare them back? Follow me and I'll... | Read more »
Intuon (Games)
Intuon 1.1 Device: iOS Universal Category: Games Price: $.99, Version: 1.1 (iTunes) Description: Join the battle with your intuition in a new hardcore game Intuon! How well do you trust your intuition? Can you find a needle in a... | Read more »
Ravenous Rampage (Games)
Ravenous Rampage 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: | Read more »
Partia 2 (Games)
Partia 2 1.0.1 Device: iOS Universal Category: Games Price: $5.99, Version: 1.0.1 (iTunes) Description: Partia 2 is a SRPG (Strategy Role-playing) video game inspired by Fire Emblem and Tear Ring Saga series. In a high fantasy... | Read more »
Puzzle to the Center of the Earth Review
Puzzle to the Center of the Earth Review By Campbell Bird on October 23rd, 2014 Our Rating: :: SPELUNKING PUZZLESUniversal App - Designed for iPhone and iPad Do some puzzles to make some platforms in this smart and fun free-to-play... | Read more »
Puzzle to the Center of the Earth – Tips...
Dig this: Would you like to know what we thought of all this puzzling-around the deep recesses of the planet? Check out our Puzzle to the Center of the Earth review! Puzzle to the Center of the Earth is a surprisingly deep and challenging puzzle... | Read more »
Sleep Attack TD Review
Sleep Attack TD Review By Jennifer Allen on October 23rd, 2014 Our Rating: :: A TRUE TWISTUniversal App - Designed for iPhone and iPad Sleep Attack TD is a tower defense game with a difference – you can rotate the layout – and it’s... | Read more »

Price Scanner via MacPrices.net

13-inch 2.5GHz MacBook Pro on sale for $949,...
Best Buy has the 13″ 2.5GHz MacBook Pro available for $949.99 on their online store. Choose free shipping or free instant local store pickup (if available). Their price is $150 off MSRP. Price is... Read more
Save up to $125 on Retina MacBook Pros
B&H Photo has the new 2014 13″ and 15″ Retina MacBook Pros on sale for up to $125 off MSRP. Shipping is free, and B&H charges NY sales tax only. They’ll also include free copies of Parallels... Read more
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

Jobs Board

*Apple* Solutions Consultant - Apple Inc. (U...
…important role that the ASC serves is that of providing an excellent Apple Customer Experience. Responsibilities include: * Promoting Apple products and solutions 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
*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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.